Green Building Forum - Housing - Renovation

Structural engineers

marsaday — Fri, 16 Oct 2009 16:49:47 +0100

Hello, i am working on plans for my loft conversion. i have had the drawings done and now i think i will need to have some structural calculations done. does anyone know any independant engineers in north yorkshire.

i have had a quote from a company and it is £700 inc vat to do the calcs, and drawings etc.

i really think this is excessive and only want to know the answer to a couple of questions.

1) can i run the joists from the spine wall of the house into the gable walls. This spine wall has a 9x2 joist sitting on it which forms a triangle in the centre of the roof which is part of the king beam holding up the roof.

essentially i will be hanging my new floor off this joist. This way of spanning the joists is the shortest and most simple.

i have a few other questions, but this is the main stumbling block.

Window frames, Oh the shame !

storm — Tue, 06 Oct 2009 15:15:48 +0100

Still struggling with the idea of what style of replacemewnt windows to have for my old cottage. Unfortunately, i have been forced, very reluctantly, to choose PVCu. A ) It is infinitely cheaper than woodframed. B ) PVCu offers u-values and security features which wood frames, as unequivically exquisite as they are, cannot compete with. C ) No maintenance is neccessary. A money and labour saving feature which I simply cannot afford to ignore. D ) Wood frames will warp and twist with the damp, losing that all important seal between frame and glazing unit .

The freezing winter storms which this little cottage are subject to are really ferocious, frequently lashing against the walls and windows, ripping up sheds ( a large metal one to be exact ) and throwing heavy garden furniture around like skittles. Am I wrong to go against the grain ( woodgrain !! ) of my ecological principles in this particular instance ? Must I be a martyr to the green cause, always, no matter how high the cost or how impractical the sustainable alternative is ?

I notice almost invariably, throughout the U.K, that the colour choice for window frames, in most buildings, modern as well as old, is white. I am unsure why there is such a strong predelection for white frames, after all, there are other hues available. I was thinking of choosing golden oak,... PVC woodgrain :shamed:

In the old days, hundreds of years ago, I feel sure the structures would have had predominantly dark frames, also, I love woodgrain....... even if it has to be imitation wood, .... , PLASTIC ! As my chosen window company rep keeps refering to them, does he have to rub it in ..... :cry:

Internal Insulation for Stone walls

richardh — Fri, 06 Nov 2009 16:45:20 +0000

We're just about to renovate our 1828 B listed farmhouse near Loch Lomond. construction is typical for the period: 600-900mm thick random stone walls (very high build quality) - the exterior stone of which was repointed (with cement-based mortar, alas) about 20 years ago - and we're not about to chip all of that off. No foundations - house is directly onto ground, with an old but watertight concrete floor. We also wish to minimise loss of interior space as we insulate the house. Downstairs already has battens in place, which create a 100mm-150mm space from front of batten to the wall.

We're advised that the best compromise on price/performance for insulation is to Use Kingspan K3 on the floor and K8 or similar on the walls (70mm in both cases), with a vapour barrier atop that and the usual 12.5mm plasterboard to face. Tricky corners and window insets we'll then face with 2L2 or Tri-Iso Super 10, where there isn't room to board. This leaves a 20-50mm air gap between wall and board, with the vapour barrier on the room side of the board. It has proved impossible to get anyone to give me sensible estimate for thermal value (Energy Saving Trust have been particularly hopeless), so all is rule-of-thumb.

Does this approach sound sensible and is there anything else we could try that will be more effective, without trashing the finances?

thanks
Richard

Condensation in "breathing walls"

bjd — Tue, 03 Nov 2009 15:34:10 +0000

I have (had?) been pursuaded to install some wood fibre insulation in place of a celotex type board with associated vapour impermeable attention to detail.

So bring on Pavatherm/ Pavadentro. I have looked at the condensation risk with these products in Buildesk U (no great experience of this). I still got a "fail" with both of these materials. So I get the manufacturer to do an analysis on the Pavadentro - being told that although this is the recommended product for solid walls, the standard Pavatherm is most often used unless damp is already a problem.

So, why does the NBT analysis pass? Because the modelled "functional layer" has a vapour resistance of 2250MNs/g - which seems massive when compared to other vapour barriers/ vapour control membranes. Their model shows a winter build up next to the vcl in the Pavadentro which dissipates through the summer. I modelled it with a breathable Tyvek VCL and get condensation occurring both at the vcl and on the cold side of the insulation against the old lime plaster. This is somewhat marginal since if I lived in the south east - the data changes and the thing "passes".

This begs a few questions (please help - I need to get on with this project!):

Should we argue that the risk analysis is irrelevant because the material will "wick" the moisture away from the condensation surface and not leave a residue/ mould growing substrate, in which case the material is fine, but the vcl is probably pointless.

OR is the condensation is still there, causing problems and the whole thing is pointless - and should go back to plan A

Incidentally - I certainly don't understand the purported issues of moisture transfer in walls. The humidity data indicates that the relative humidity is ALWAYS higher on the outside than it is in the house, admittedly and a lower temperature. I understand that the higher temperature air can carry more moisture at the same RH, but it makes a nonsense of trying to say the moisture is travelling one way or the other. It is more a question of saying is the temperature gradient such that the RH is greater than the dew point - i.e. it is the heat that is doing most of the moving, not the moisture. Thus a vapour barrier on the warm side of the insulation makes most sense since it allows the partial pressure to drop immediately - not sure I am explaining myself very well here.

Maybe I am just dissappearing up my own ****! Help!

Minimising concrete use for underpinning?

dan_aka_jack — Mon, 02 Nov 2009 11:08:17 +0000

We're renovating our living room. We have to underpin our load bearing internal walls (it's a long story). The current plan is to temporarily support the walls at regular intervals, dig out the earth under the walls and pour all the concrete at one go.

Are there any alternatives we could consider to reduce the use of concrete? As far as I can tell, the options aren't great:

* Limecrete simply isn't rigid enough to act as a foundation (it sheers far to easily)
* It would be physically possible to construct a steel "foundation" supported on piles but we'd have to take the bay window off the house to get the piling machine in!

Are those statements correct?

Are there any other options???

We will be increasing the room's insulation by a factor of 7 so I'm reasonably comfortable that our refurbishment makes environmental sense. But I'm eager to minimise the impact when we can!

insulating our loft conversion bedroom

biff — Tue, 03 Nov 2009 17:13:00 +0000

Hi
Our loft bedroom has no insulation between the plasterboard and breather membrane under the tiles. There is only 100mm between them.
Is it sensible to:
a) fill the whole gap with insulation?
b) blow in cellulose insulation to avoid major disruption to our house?
I appreciate that I can, and will, also add insulated plasterboard to the underneath.

Renovating living room: int insulation, low thermal mass, electronic heating controls

dan_aka_jack — Wed, 28 Oct 2009 11:09:47 +0000

Hi there,

I'm not a trained engineer or architect - I'm just a DIYer who's trying construct the most thermally efficient living room we can. My main question is: am I right to opt for leaving the radiators (rather than converting to underfloor heating) and opting to not add thermal mass to the newly constructed timber floor?

We're renovating the livingroom of our end-of-terrace Victorian solid walled property. External insulation isn't an option so we're using 75mm Kingspan on the internal surfaces of the external walls and we're completely rebuilding our suspended timber floor with 120mm Kingspan between the joists.

The internal walls are all made of a single layer of brick and so must weigh several tonnes so the room will have some thermal mass, no matter what we do.

I've been considering 3 different permutations:

1) Leave the radiators as the only way to heat the room on a winter's night. Don't add any thermal mass to the floor (i.e. install the Kingspan so it is immediately below the floor boards). Use electronic room thermostats and a zone valve to ensure the room doesn't overheat in winter with the heating on. Install a fan in the corner of the floor to pull air through the underfloor void and into the room to cool the room in summer (i.e. a way to connect the room to the substantial thermal mass of the clay under the house). Install a single room mechanical ventilation unit with heat recovery to keep internal humidity and "stuffyness" under control.

2) Same as option 1 but add a 25mm layer of sand+cement immediately under the floor boards to add about a tonne of mass within the thermal envelope of the room.

3) Remove the radiators and install underfloor heating under the timber floor, with a 25mm layer of sand+cement.

I'm opting for option 1 for several reasons and I'd really appreciate any advice... my reasons:

We only use the living room for short periods in the evening (maybe 1 or 2 hours on average). We work odd hours so it's not always possible to predict when we'll be in the living room ahead of time. Hence we want the room to heat up quickly. e.g. my wife and I decide at 10pm "OK, we've done enough work for the day, let's go and watch News Night and an episode of Family Guy".

I did some back-of-the-envelope calculations and figured out that underfloor heating with 25mm of sand+cement would take about 2 hours to increase in temp by 20 degrees C. Not fast enough!

Yes, the room does receive some solar gain through the windows from sunrise until about midday but I assume that even if we add 1,000kg of sand & cement under the floor, the temp rise caused by the morning solar gain will have long since dissipated by 10pm (not least because we haven't yet insulated the rest of the house).

Any advice would be fantastic!

I suppose another way of answering this question would be: is there a free (or cheap) thermal modelling application I could download and tinker with to explore the options? I have a little bit of experience with CAD and 3D apps.

Many thanks,
Jack

Passivhaus refurb

DavidThorpe — Mon, 26 Oct 2009 09:03:31 +0000

To anybody's knowledge have there been any independently assessed successful Passivhaus refurbs anywhere? I mean work done to the full PH standard with what would be the equivalent in academic terms of a peer-reviewed corroboration by follow-up performance studies done on the homes, for example in any of the EU programmes on social housing? Can anyone direct me to any academic papers, for example, please?

Thanks

David

how to make a partition wall airtight?

visitor — Thu, 22 Oct 2009 17:33:47 +0100

Hi,
I've got a problem. The partition wall between my top floor bedrooms is leaking air. It is not just the sockets but under the plaster where the wall meets the floor. On all ceiling down lights I have installed airtight mdf boxes /pot planters per Tony's suggestion. I am trying to avoid to have to take the ceiling down or redo the wall.

Any ideas how to seal that wall?

Celotex v Warmcel for suspended floor insulation

andykent — Thu, 03 Sep 2009 14:23:57 +0100

I'm about to insulate a suspended timber ground floor in my Victorian pile and had had every intention of using Warmcel because of its non-toxic, sustainable manufacturing method. But, because of the greatly underspecified joist depth (3.25"), I'll need something to go underneath to make up the U value and because I only have access to the (16") space beneath the joists from above I favour a lightweight material such as 2" of Celotex rather than awkward, heavy wood fibre boards.

The plan was to fill the space between the joists with Warmcel with the Celotex forming a base and then place a breathable membrane such as Tyvek or Permo over the joists to protect the Warmcel against spills. But with at least half of the volume of insulating material already slated to be Celotex (I'm also going to take the opportunity to double up every other joist to fix floor deflection problems which will further reduce the between-joist volume), is it worth the hassle of including Warmcel?

I'd welcome people's comments.

Thanks,
Andy

Internally insulating old walls - a definitive answer?

bjd — Mon, 21 Sep 2009 12:54:05 +0100

I have just had a thermal study on my house - it confirms that insulating the older walls would be a good thing: cost effective, and saves C02 - it has to be internal (Peak District National Park).

I have read a lot of the threads here regarding this topic and I am surprised that the debate is still so strong, with nothing definitive coming through (as far as I can see). So a few questions:

1) Wall construction is approx 250mm Peak district stone, aprox 100mm rubble filled cavity, 100mm brick, wet plaster around 15mm. U value estimate is 1.94 (reasonable guess). Proposal is 50mm PU/ plasterboard laminate insulation achieving U value of 0.567 (yes - to 3 significant figures). My calcs would suggest something closer to .35, this is an issue since 0.567 won't satisfy the regs! Any thoughts anyone? I will be going back to the consultant, but wanted some comments first.

2) Has the BRE or some other neutral body not done some work on a recommended solution to internal insulation? - I have read the Energy Savings Trusts report (see EST website), but it seems a bit glib about condensation problems - and no long term feedback.

3) Anyone want to throw a recommended solution into the mix? My favorite is Mike's laminated boards attached to Horizontal battens - with a membrane in there somewhere - although the air gap left will not have any ventilation as such - just an enclosed air gap as I see it (although I don't think I have quite got me head around the detail yet). Feel free to point out an existing thread if it's relevant, there quite a bit on this out there!..................

Doing up a '50s concrete maisonette

architectonics — Fri, 23 Oct 2009 14:14:12 +0100

Hello,

I'm after some advice about improving my '50s upper level maisonette.

The freeholder council will do the cavity walls, install double glazing and bring the roof up to regs, I'm planning to fit insulated plasterboard, install an air-source heat pump, and do some sort of ventilation.

For the walls, do I need to remove the existing plaster, which sits in front of an air gap between it and the in-situ concrete walls. And will I need to do anything about airtightness here? Or is in-situ concrete pretty draughtproof anyway? Even if there were a few cracks, the wall cavity isn't ventilated anyway.

We all smoke loads, so I'm thinking about some kind of heat recovery ventilation. I've heard you need top notch airtightness to make these viable. Is this going to be plausible with a '50's concrete building? Or would a Suncatcher type device do? Or one of the solar powered dehimidifiers I've seen advertised?

I also would like to pop a skylight over the stairs in the flat roof, but I'm worried I'd loose a lot of heat through it. To what extent would this be offset by solar gain? Ought I really to go for a sunpipe?

Thanks!

Warm Roof Ventilation, on a 30's bungalow loft conversion

richjenn13 — Thu, 22 Oct 2009 16:18:02 +0100

I have a 30's bungalow with an inherited non-regs loft conversion, fitted under a very splendid new roof, sadly installed over non-breathable underlay, rather than a breathable one, despite both things apparently happening within 12 months of eachother - bah!

The insulation is 50mm Celotex cut to fit betwen the 100mm rafters, but with no eaves/ridge ventilation installed to provide airflow to the void between the Celotex and the underlay.
Then 12.5mm plasterboard has been laid over the underside of the rafters and the faces of the cut Celotex, & skimmed to finish.

I want to get this to a proper standard.
It would seem to get sufficient u-value, a cross layer of Celotex - 35/50/more? - under the existing layer would be necessary, so taking down the plasterboard seems common sense. Leaving in it place, and re-boarding over the extra insulation layer would add to weight load, and seem a bit crazy all round!

So, if I have to pull it down, why don't I cut away the underlay from the underside of the tiles? This means that I can replace the 50mm Celotex between the rafters, cross board with another 50mm Celotex, and plasterboard, and the void between the "slates" and the inset Celotex will be ventilated through the "slates", avoiding the nightmare of trying to retrofit eaves and ridge ventilation to an otherwise A1 roof covering.

Which leads me to my "big"question. All my previous old houses have had slates attched to battens with NO underlay of any sort, and are still doing fine after 80/90 years. My understanding is that the fitting of underlay between slates/tiles and battens on new roofs is;
a) to make things waterproof quickly in case it rained befroe the slates/tiles could be laid, and
b) to duct water down to eaves should a slate/tile fail, rather that water leaking into roof space - and down to ceilngs etc.

I have seen a loft conversion done on a roof without underlay. The BCO was far from happy, apparently, but couldn't point a finger to a reg that dis-allowed it. Honestly I cant see why there's a problem, but surely the plan B solution could be to cut away the non-breathable underlay as posited, and then attach a breathable membrane from below, fitting it into the space between the rafters and taking it down the rafter face, over the bottom of the rafter, back up the other face and so on. Thus the rafters would be wrapped in membrane, but there would be a continous barrier in case of water ingress. It feels counter-intuitive, but the rafters would still be ventilated, as would the void.

I'd be most interested to hear opinions on this - am I missing something obvious?
Cheers
richjenn13

Vermiculite as roof insulation

jerseyman — Thu, 22 Oct 2009 14:56:29 +0100

I have an area of my attic above the dormer that it is not possible to access to lay rockwool type insulation.

With a great deal of patience I reckon I can use a can on a stick to distribute loose fill insulation over the offending area. The problem is that here in Jersey the only loose fill insulation I can find is vermiculite (Micafil). A quick search on the forums has turned up topics on using vermiculite for chimney insulation, or on how to re-use vermiculite. This does not fill me with confidence! The other area of concern is that the Micafil web site specifically avoids quoting a U-Value

Is my intended use of Micafil OK? and are there any issues I should look out for?

Brian

Insulation of a sloping roof

Chris Wardle — Tue, 08 May 2007 13:12:07 +0100

Spent part of the bank holiday poking about in my in-laws loft which I have offered to insulate for them before winter. They have a bunglow with rooms built into the loft which has been extended and mucked about with in the past without any thought given to insulation of the roof.

There is a problem area between the roof voids at the eaves and the void around the ridge which I'm not sure how best to tackle. Rafters are 100mm deep with lathe and plaster sloping ceiling below and roofing felt, battens and concrete tiles above. House has been re-roofed in the past but no insulation was added to this area. The roofers also failed to clear out the bodging off the back of the original tiles so there is some debris in the 100mm void between the rafters.

Any suggestions of how to insulate the sloping section of theis roof this roof? Best I can come up with is trying to slide 50mm Kingspan boards betwen the rafters from the bottom and top but it won't be easy because of all the rubbish in there. I've also thought about filling the whole of the void from the top with polystyrene beads but this would cut the air flow off between the ridge and eaves - think this would be a problem? It is actually cut off at the moment as father-in-law has stuffed a piece of mineral wool in between the rafters top and bottom... There are not keen on insulating on the room side of the ceiling as they have recently decorated and I dare not suggest stripping the roof!

My Loft conversion - roof insulation

marsaday — Fri, 09 Oct 2009 11:56:50 +0100

Hello, my first post!

I am reading a lot of info on insulating the rafter space and would like to get your opinions. i have a few questions for you all.

Background: Simple pitched roof, 1910 build, perlins to stay, adding a few velux. A basic conversion. lots of head room so no problem with space. The roof is back pointed tile in very good condition. so no need to add a breather membrane.

My Building control officer is private and is very relaxed about some aspects of the renovation. He is happy if i put in just 100mm of celotex type insulation. however i want to go slightly better than this. So i am open to suggestions using multifoil because he will pass this as well.

Questions:

Will i be ok leaving a 20mm breather gap between the insulation /rafter space and the tile?

I was planning on going for 80mm between the rafter and 50mm on the underside. i think this passes no problem. i have read using a multi foil on the underside is a better option. any comments?

do i need to use a vapour barrier on this renovation? Would it go between the rafter and the underside layer of 50mm celotex? I have been told the celotex insulation acts as a vapor barrier. correct?

I am going to be relaying the roof ridges and so should i build in 2 breather ridges when i do this?

Thanks

Kitchens - made of green MDF?

Imogen — Thu, 22 Jan 2009 13:42:20 +0000

I have been researching kitchens and a number of the designers suggest using green MDF instead of natural wood as they say it is more resistant to kitchen environments. Apparantly solid wood tends to move and ultimately crack over the years and green MDF is more durable. As kitchens are so expensive, I want to get it right, so any comments would be helpful.

Garage Ceiling Insulation

jemhayward — Wed, 14 Oct 2009 12:58:04 +0100

In process of barn conversion and I'd intended fitting celotex between the rafters of the garage ceiling and then adding fermacell or multipro boards as my firecheck. Then someone mentioned the fact that celotex melts when hot and drips through, causing even more problems (though by then I'm probably in serious trouble). One of the appeals of celotex was the relative ease of making the floor wind proof as the floorboards are not T&G.
So what should I be looking at? I suppose I could fit a plastic membrane above the final finish board, but my vapour barrier should really be on the warm side of the insulation. Lifting the whole floor would be difficult as the upstairs wall insulation sits on the ends of the floorboards!

On demand ventilation

brig001 — Sun, 18 Oct 2009 11:40:22 +0100

As the house is getting more airtight, I am looking into ventilation. HRV is obviously quite a major expense and was looking into these http://www.aereco.com/int/uk/product.php?product=emm as a lower cost option. Does anyone have any experience of these or similar?

Thanks,
Bri.

Guidance for a 1950's bungalow

bigsidney — Wed, 14 Oct 2009 08:31:25 +0100

As a new forum member its been very educational scanning all the old posts , but its probably time ask for some views on my own project.

Background: 1950's bungalow , 50mm cavity walls, timber floor over airbrack vented void. currently 130m2

Plan: Maintain floor plan but add a complete new roof to add about 80 m2 of room in loft.
Luckily the neigbouring properties have had similar modifications including raising roof lines , so fingers crossed the planning will not be a show stopper.

Objective: Rebuilld the house to a good energy efficiency standard. I'm not on a crusade, but I would like to feel that I had done the renovation resposibly for the future. As such the actuall payback is not the deciding factor, but this is more about living in a house that I know is more energy efficient than most and being able to tell the kids down teh line that we at least tried to do the right thing.

Current thoughts / questions.

Plan to leave current extior walls (but thats about all that will remain) . Am assuming only option is to loose cavity fill.
Roof is probably going to be cut timber with rafters >200mm so should be plent of room for insulation between rafters + another 50 mm on the back of all of them.
Floor is one of teh aireas i'm unsure. Would like underfloor heating and I realise I need to insulate in some way as the draft coming up at the moment is criminal !. So options appear to be insulate between joists and lay UFH in the top of the insulation , or lay a new concrete slab with insulation built in and then lay UFH in screed on top.
Glazing will be triple on N facing wall and double E on S facing walls
Planning a heat recovery ventilation system, and realise that I will have to get the builder to do everything he can on the airtightness of the fabric of the house during the build.
Solar water heating appears to be a no-brainer as does rainwater catchment as both will be easy to do during such a major rebuild.

Am an engineer by trade, so can get my head around technical stuff , but this is a first time house renovation so any advice is very welcome.

Thanks

Internal wall recommendations

simeon — Fri, 16 Oct 2009 11:09:25 +0100

Hi all,

In the next couple of months, we are going to renovate a bedroom which has a north facing wall with dg windows. I want to properly insulate this wall internally as external wall insulation is not feasible. The windows are dg and have an area of about 6m2. The wall area is about 7m2. I am very reluctant to use a dedicated dry lining firm as these seem to be expensive ( circa £1000 per wall!) but I can source the services of a capable carpenter. However, my experience indicates that it would be best to buy the material myself and present to the carpenter for fitting.

From reading the many comments on this board, I reckon that it would be a good idea to have thick wood batons surrounding the window frames (perhaps 100mm plus square) and have secondary glazing supported on these batons over the windows which will improve the insulation over the dg and reveals but also help with street noise. To insulate the wall, I am thinking of removing plaster and using 75mm wood vertical wood batons between which wall insulation will be placed, and on top, plaster board panels with 10mm polystyrene backing.

Is this a sensible idea?

But what wall insulation? I was told once, that the rigid mineral wool slabs are not suitable for iwi. So, do I have to use polystyrene slabs or kingspan? Do suppliers actually supply low quantities? In my case, only 7m2.

Your comments would be appreciated.

Simon

Corrugated roof

clovercott — Wed, 14 Oct 2009 17:22:45 +0100

Hello I am renovating an old farmhouse in Ireland and am building am extension at the back. The main building is thatch but I cannot afford to thatch the extension. As the two surrounding buildings are corrugated I was thinking of extending the theme to my extension. Does anyond have experince of contsructing a dwelling using corrugated steel as the roof, I have hear that there may be noise issues when it rains but intend to insulate it starting with plywood on top and rockwool in between the rafters.Comments please.

recommend a NON Breathable Paint ?

wellburn — Sat, 10 Oct 2009 00:23:35 +0100

Having read every thread, I decided to internally insulate my attic, and having fitted, filled, and sealed to the very best of my ability, - my final task is to seal my freshly PLASTERED ceiling.
It does break my heart, compared to all the lime restoration I have done elsewhere, but this bit if ecovation requires a final airtight seal.
Condensation study says GLOSS paint. Don't want to do that, it's inside the house, guests sleep there, even I sleep there if I've had more than XXX beer.
So I have insulated. airtight sealed. Gypsum plastered, and am still fearful of condensating interstiller moisture lader air, and the computer says GLOSS PAINT to make condensation risk be zero. Keep it all inside.....?
What can I use ?
need to treat 1 month old fresh plaster.
plaster to timberwork joins etc.
A good coat of gloopy thick oily slop might make the whole thing airtight, but is there anything a little more natural?
Wellburn??

PS - If you must question my thinking, - please also recommend an eco non-breathing paint!

roof ventilation and insulation

miltwin — Mon, 06 Apr 2009 13:21:19 +0100

I'm a little new to this so bear with me if I've missed the blindingly obvious.

We are re-building a small granite barn (6m x 3m) for 'ancillary accomodation' and, despite reading and reading, I am a little concerned over the roof ventilation between slate and batten.

The barn is being re-built as a breathable building, i.e. lime used throughout, etc. The pitched roof will have 150mm sheepswool insulation (no air gap), a klober perma-forte membrane, battens and then wet-laid slates.

The issue I can't resolve is whether I should be using counter-battens:

- to allow run-off of vapour condensing on the back of the tiles/slates?
- to provide adequate ventilation?

I realise that there is probably not enough insulation in the roof but this is a necessary compromise for headroom. We are restricted on overall height as we live in a conservation area.

What boards to people recommend for supporting the wool/underside? Pavatherm Floor NK? I'd like to avoid plasterboard.

Thanks for any advice given.

Robin

Combining Gas boiler with Solar, UFH, Heat Bank....

cromar — Tue, 06 Oct 2009 15:23:25 +0100

Just a quickie and what I hope will be a simpleish topic...

I'm adding an extension to my 30s house. The heating at the moment is gas fired Viessmann Vitodens 200 boiler supplying DHW via a tiny cylinder and CH.
My plan is to keep the boiler - too expensive to replace - and have CH running from this still. The new rooms, will be UFH running from the Heat Bank (300l DPS Excel). Also being added will be two solar panels (Vitosol 200) and a wood burniung stove with back boiler all firing into the Heat Bank. The boiler will heat the Heat Bank and all DHW will then come from the Heat Bank.

All the new build is specified with a lot more than the statutory required insulation.

Any comments on this set up gratefully received. It seems OK to me and to my polumber who has put in loads of this type of system before. What do you think??

Dave

Insulation to pitched roof

layperson — Sun, 15 Feb 2009 22:16:53 +0000

Hello everyone. I have read with interest the discussion and as a lay person, i find it very helpful. I will be brief:
My house was originally built in 1700 and is not listed. It is on 3 floors and the top floor is where we sleep. It has exposed beam work and has a pitched roof. It is very pretty but sometimes leaks. The renovation work started in Oct 2008 and due to end in May 2009! A big conversion beleive me.
My builder has removed the pasterboard to the pitched roof and the Rockwool is discoloured, is 2 layers deep (I estimate it is 8 to 10 inches), but we suspect most was done around 30 years ago (some improvement works were done about 7 years ago and there is some different coloured rock wool going on). The builder is putting new plasterboard back (with no insulation properties: just plain plasterboard). I am concnered about the following:
1) Should i be using a insulated plasterboard (e.g Kingspan 50 mm) or Spacetherm?
2) Would his exisiting solution pass Building regulations?
2.5) Would his solution allow for air pocket to allow ventelation ?
3) Given that i have leaks, should he not take out the rock wool and chekc for leaks (e.g where the felt has broken)?
Help please!!!
:sad::sad::sad::sad::sad::sad:

old loft insulation

marsaday — Sun, 11 Oct 2009 16:08:33 +0100

When i come to convert my loft i will be laying new joists above the current ceiling joists.

i will fill these joists with 200mm of new mineral wool i have laid in the loft recently.

however, there is still a mucky layer of old insulation between the ceiling joists. Should i remove this and bin it. is it really doing a good job.

i am inclined to remove it to make works access easier when putting in the new floor structure. Also i would like to hoover out all the old rubble and dust that accumulates in here.

Insulated garage doors

wookey — Wed, 02 Sep 2009 23:33:33 +0100

We are planning a small extension to cover bit between house and garage/store which will also have a sunroom bit tacked on the end of the sheddage. The new bit will be built to as high a standard as I can justify (given the inevitable thermal bridges where we attach to the garage.

Making the garage (workshop really) warmer, lighter and bigger (flatroof->pitched roof) is part of the plan. One glaring issue is the garage door. Currently a 1960s up-andover with about a 5cm gap all the way round so very easy to improve on. I really need to keep access for moped storage but there is no desire to ever put a car in here.

Is there such a thing as a well-insulated garage door? (i.e U < 2.0, preferably better). I could split the entrance in half and have a wide door for getting the bike in through and fix the other half. Again suggestions for manufacturers welcome.

I don't know if the planners will insist that it remains looking like a single door even if it's not. We have yet to ask that question.

is a french drain an opportunity for external insulation?

spoonandfork — Mon, 14 Sep 2009 01:16:02 +0100

I'm installing a french drain around the perimeter of a solid brick / stone building. Is this an opportunity for some external insulation? The building has concrete slab with UFH and 80mm phenolic perimeter insulation inside. Bit apprehensive about preventing brick from breathing, it's potentially taking more than its fair share of damp thanks to slab's dpm. Any advice on what type of external insulation would be appropriate? Drain is not taking massive load, just the run off from length of adjacent concrete which is 2m wide (building is 10m long), brick is 350mm thick. Other side is 10m long as well and is surrounded by grass/soil which thankfully slopes away from the building, this is 800mm thick stone though, not brick. Might dig about 400mm deep for the drain, but if installing insulation that is useful am prepared to go maybe 800mm (don't want to undermine foundations).

Insulating Hall/Stairs - Suggestions please

john_g — Mon, 28 Sep 2009 20:18:45 +0100

While most of the insulation discussions on the site are for terrace properties. Some of us 4 walls to deal with, my problem applies to most semi’s as well.

External insulation is not an option - unless the law is changed. = Detached house, my south facing wall is the driveway of next door (complete with carport), and my driveway has my other neighbours wall. This makes it almost impossible - as the drive would become too narrow if both properties did external insulation. I don’t fancy the legal battle let alone planning fight and access.

Can anyone suggest a way of insulating my stairs to a reasonable level? Approx. 30mm of wood visible.
1, In an aesthetically pleasing way.
2, Without ripping out stairs.
3, Dealing with thermal bridge of stairs.
4, How narrow can a staircase be?

John_G:bigsmile:

Solar Thermal/PV, Woodburning Stoves & Heat Recovery

itsgrimupnorthlondon — Tue, 21 Oct 2008 20:02:52 +0100

Hi all,

First, I'd like to say what a fantastic community. I've been lurking for a while and now I feel it's time to give in and start asking for some wise words! :bigsmile::bigsmile:

So, we're about to start on a side return extension and renovation to our ground floor Victorian mid terrace flat conversion in London. Being typical Highbury types we're trying to do it as green as possible. So far we've got planning permission and sorted out the core materials.

We also applied to the Islington Council Climate Change Fund. The result was we've been given a grant of £2000 towards a solar thermal install, and £2000 towards a PV install. In addition we should also be able to get £2500 from LCBP grants. Islington Council say this means we could have a Thermal system installed for £2100 and a 1.3kW PV system installed for £4200. The roof these would be installed on is a SSW facing ~35 degree slate roof.

Along with the grant proposal, the council also gave us estimates for money saving, payback time and total CO2 savings based on the gas and lecky prices and consumption we are currently paying/using. The results were:

Solar Thermal:
Annual savings - £57
Payback time - 36.6(!) years

PV:
Annual savings - £221
Payback time - 19 years

And so, the questions!

The solar thermal savings and payback seem mental. We're using an old combi boiler right now. Is there any way can make the thermal go further and save us more? I was considering a thermal store and backboiler wood stove. However, there are none which are smokeless area OK and OK with a closed system. I've seen the Dunsley Yorkshire, but it seems to need a vented system.

The PV seems a little more sensible, but I've read a lot on these forums about new PV technology. Is now the wrong time to jump into PV, or is the grant too good to turn down?

Third, I've searched high and low, but I cannot find any experiences with MHR in flats. Is it worth it? We're going to be sealing up and draft proofing as much as possible, so ventilation will be important. But before we put piping into each room I would like to check any experiences on their installation in smaller houses/flats.

Lastly, I'd ideally like a woodburning stove for the front room which can take an external air supply. There doesn't seem to be any point at all in having an air brick sucking cold air in if we can help it. We are tempted by a Clearview stove, but I can't find any info on external air supply. Additionally, the stove will be 3 meters from an exterior wall. Could I run the air supply under the floor?

Well, that's it. I'm sure you'll agree that's enough for one post. Apologies if there are stupid questions, I'm a bit of a noob to building in general.

Many thanks in advance!

Matt

Old floors need leveling.

storm — Mon, 21 Sep 2009 13:07:19 +0100

Anyone got any miracle ideas for leveling out old floors ?

Very old Welsh cottage. Two upstairs bedrooms, with annoying sloping floors, may well be quaint and fasionable, but I like the idea of being able to place furniture, securely, where I want it. Instead of having various wobbly tables, etc, with pieces of cardboard underneath in the attempt to gain symmetry. Also my bookcases may well end up collapsing on top of me. :shocked: What a way to expire under a shower of heavy books. Mind you, being buried alive under the weight of Shakespere, Blake, Tolkein, Plus those comprehensives galore,... Grow your own veg,.... ..Discovering crop circles, Bears and their habitats ...........come to think of it, What a way to go ! Maybe I should keep the lopsided floors after all , to accelerate my high vibration exit into the greater beyond ! :bigsmile:

I have wandered off my subject yet again ( which often happens .. ) Back to basics. Problem is, Very old, probably unstable, cottage floor. Underside ( Which is lounge ceiling ) Black painted beams ( incidently I want them stripped, prefer beautiful exposed wood ... still unsure if they are the original beams though .... )

To straighten or not to straighten, that, is the question, back to Shakespere :neutral:

The bedroom ceiling height is already rather low as are the doorways, so the leveling must not take up more than an inch or so, and needs to be strong yet feather light so the whole lot does not collapse. Yes, there is a large central beam downstairs but the ceiling already looks a little bowed. Any tips on how to do this economiacally with as little disturbance to main structure as possible, most unlikely there is a solution, but all the same ....

Longevity of EPC 'Balls' and Expanding Foam (snow in Summer!)

Gotanewlife — Sun, 27 Sep 2009 19:39:09 +0100

Short Qs:

1 - How long will many thousands EPS balls last in my garden before breaking down?

2 - How long will single component Polyurethane Foam for fixing roof tiles remain effective on my roof? ……. Which kind of leads into the question:

3 - Should I use a nice strong OPC for the perimeter tiles?

The Same Qs but longer story:

Task in hand (skip this bit if in a hurry!): pressure wash all the roof tiles; remove tiles; clean roof of 200 birds nests, 30 year old concrete and all rusting galvanised flashing/facia boards; lay 10+4 ventilated EPC boards and water/vapour proof roofing fabric on one side; lay 100mm EPS boards backed with bitumen on the other side (over a plastic vapour barrier and the 60 odd 10mm SS rods for my PV and solar panels); lay additional layer of re-enforcing bitumen over all edges, bends etc on small side; lay copper covered bitumen to parts when there will be no tiles and not covered by panels; add 26cm deep copper facia boards to dormer and gable ends, fit copper gullies, put up copper gutters including complex shaped ventilation section; cover small side with final layer of bitumen; relay all tiles tiles then call in the man to fit all panels. Oh and fit 2 sunpipes, 2 copper chimneys and remove existing MASSIVE chimney.

So I went ahead eventually in a big rush – “order by the end of the week or you'll miss the summer” they said. Months of planning went down the panic tube. "No you can't have 80mm of EPS they only make it up to 60mm in stock, there is not much call for anything thicker - normally be 3 weeks except there is Aug in the way"

Anyway, cutting the long story, I got '100mm EPS-40mm Ventilation-1.2mm OSB' in 2.44x1.22m sheets for the big side and for the side where I have to raise the roof 80mm around my 24 Solar Panels in order to get the largest grant - 100mm EPC with bitumen in 1.22x1m sheets plus twice the m2 I needed of 40mm plain EPS for the higher bits

(PS I should add: I live in Italy; this is a fully DIY job; I had no scaffolding because I am not allowed to DIY if I have scaffolding; I was not required to meet any building regs;)

The roof was serious un-straight consequently I had to variously shave channels, cut great big chunks and generally shape many of my boards. Only way in the end was to use a chainsaw. Result: we sat down to lunch in 35 degrees outside the wind got up and it snowed! So anyone know how long before all these damn balls will breakdown?

Now about to put all the tiles back, going to use one-part expanding (low rise – US term) foam specifically for tiles but the question is does this stuff last ‘forever’ and should I use OPC for the perimeter tiles?

Barn conversion - Normandy, France, sources of information

DarylP — Fri, 04 Sep 2009 21:36:41 +0100

Does anyone have any sources of information, or indeed suppliers of insulation, in or around Normandy. We are considering converting a stone barn in Normandy, and want to reduce our energy demand as much as possible. Were thinking of insulating (external/internal) , solar DHW with biomass boiler/stove backup, as much 'off grid' as possible.

This is just a toe in the water, we don't intend to start work seriously till next spring, just gathering ideas at the moment.

Thanks in advance.....:smile:

Polyurethane Foam Cavity wall insulation?

Radioman — Sat, 25 Oct 2008 01:03:27 +0100

Hi i am new here so hello:bigsmile:

I am currently improving all aspect of the insulation on my 1930s semi and i am in the process of getting grant assisted cavity wall insulation. I have done much research on the subject and will probably opt for Polystyrene balls (bonded) however during my research i have discovered all U values for cavity wall insulation are similar 0.040 apart from Polyurethane foam which is quoted as 0.020, my problem is nobody seems to offer this as an option for cavity wall insulation, i am assuming there is a good reason for this like damp, cost possibly?

Cavity fill installation is somthing which can't be reversed so i want to get it right first time and achieve the best U value for the wall for the 65mm cavity i have available. I don't want to just go with the normal materials only to find out i could have doubled the performance of the insulation for a little extra cost.

Has anybody had any experience with Polyurethane Foam in cavity wall insulation, or done some deeper research, any advice or tips would be greatly appreciated.

Thanks Radioman

U values with secondary glazing

bjd — Mon, 21 Sep 2009 13:06:36 +0100

My new house has a number of 1920's sash windows with internal secondary glazing - sliding panels with brushstrip seals around the edges (Everest I think, less than 10 years old).

Just had a thermal study done to try and highlight the areas that need attention - the report has used a U value for these windows of 2! Older 4/12/4 dg windows have been rated at 2.8, so I find it hard to believe that 2 is achievable with the secondary glazing (gap is around 100mm).

Has anyone got any experience of the typical U values when such glazing is used? It rather drastically affects the numbers in this study. I did a heating demand calc on the house (such as you would do to size a boiler) and used 3, but don't really have a clue.

Creative DIY should allow me to renovate the windows at a low cost to around 1.5, but if we are already getting around 2 then it would be a waste of time - apart from sorting out the masses of condensation we get on the outer panes all winter.

Thanks for your help.....

Vapour Control Layer

ma701ss — Thu, 24 Sep 2009 10:26:45 +0100

Celotex state that joins on their insulated plasterboard should be suitably taped to create the vapour control layer. They don't describe what suitable is. Would using scrim tape and skimming over be suitable, or should aluminium tape, for example, be used instead?

Wet UFH on top of existing boards - insulation advice reqd

ListysDad — Thu, 24 Sep 2009 00:50:11 +0100

At last, a forum where people talk sense - well mostly! :bigsmile:
I've a 150 year old house with lovely high ceilings that we cannot get enough heat into with rads as there isn't enough wall space to hang 'em (don't ask!!!)
So, I've had the John Guest rep out and he's advised UFH which by the calcs will do the job.
My 'problem' is that the old (boarded) floor has to stay and a new oak floor will sit on top. He's suggested 18mm laths spaced at 400mm interrvals (for secret nailing the floor) and the UFH pipework run in between.
What's best to fill the void left? Is there anything 'useful' I can put down under it all (on top of the old floor but under the laths) to minimise heat loss downwards?
As the floor void is pretty drafty, I'm loath to put down foil as everything I've read says it's sh*te generally, and worse in those conditions, but I simply don't have the space to put in kingspan or whatever as I need a seamless transition of levels into other rooms on the same floor for a whelchair user.
I hope that all makes sense?

insulating a solid wall - newbie help please!

droffilc — Thu, 17 Sep 2009 22:21:17 +0100

hi there,

I live in a 3 bed semi house with a loft conversion. It was built between 1920 and 1930's (i think) (the loft conversion was done about 4 years ago) and I have walls without a cavity :-(

Winter is coming closer and within the next month I want to insulate my solid walls (internally) mainly in my hallway, my 2 year olds "box room" and walls in the two other bedrooms that are outside facing walls (very cold to touch!)

I've searched the internet and looked through some of the pages on these forums and I think the products i should be are:

1. Sempatap
2. Thermalite paint (to apply after and then my choice of paint or wallpaper)

I would be grateful if the knowledgeable members here could confirm / verify that my product choice is the right one please?

My main priority of course is to increase the warmth in my house without loosing too much width from my walls. Budget is not an issue however I want to ensure i do the job right the first time round and i think product selection and how its applied is key.

Many thanks for reading and your time, I look forward to your feedback

Regards, Cliff

Yorkshire sliding sash

blacksmith — Tue, 08 Sep 2009 17:00:57 +0100

Does anyone have dimensioned (proportional) drawings they would be willing to share or know where I could find drawings to make up a Yorkshire type-sliding sash from?

Failing that - any book/other recommendations that might have enough detail to work from. I will be using oak.

Cheers

Conservatory - can I design it to be useful?

Barnacle — Tue, 01 Sep 2009 21:03:48 +0100

I have a crumbling conservatory that is timber framed with single glazed glass walls and a plastic corrugated roof. It faces South West on the back of my house and we find it very useful for drying clothes (esp. in the Winter) and housing our washing machine. It really is about to fall down. So I am going to replace it.

I am looking for advice on how it can be designed to be:
- cheap(ish) to construct and maintain
- not overheat in the summer (the current conservatory doors are missing so this is not a problem!)
- warm on sunny days in spring, autumn (and even winter?) so we could open our back door and it would warm the kitchen, as well as dry clothes
- still classed as a conservatory from building regs perspective - i.e. roof is glazed.

My current thoughts are:
- opaque glazed roof to limit solar gain in summer (apart from a glass section near the back door to let light in for the kitchen)
- glazed walls to give solar gain in spring, autumn (and even winter)
- need to keep design light weight as the foundations don't look strong to me and I don't want to put down new foundations
- not heat the conservatory at all
- try and have it built from timber frame (not UPVC/aluminium).

One pressing question that I would find useful to be answered is:
- is it better to have single or double glazed glass 'walls' for solar gain in spring, autumn (and even winter)?

Many thanks.

I have read thread:
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=362

Underfloor Heating question

Andy M — Wed, 16 Sep 2009 16:53:40 +0100

I want to install wet UFH in a house we are renovating asap but at some point in the not too distant future I want to do the same in the adjoining barn when we get round to converting it. As the barn is on the other side of house to the boiler so to speak and the only path through to it is via the floor I want to lay now, is there a way to lay extra piping and then cap it off where we will knock through or is there another tried and tested method for such circumstances? Various searches on Modular, extendable, expandable etc haven’t really helped so any advice would be greatly appreciated.

Andy

Timber sash and case double glazed windows

jwd — Wed, 15 Jul 2009 21:52:49 +0100

Hi All

My project planning is moving apace and I need to start thinking about window suppliers. I have to replace about 8 old timber windows. Most are way beyond repair and the ones that arent are on the very sunless and windy parts of the house so it makes sense to replace the lot while I insulate to house internally.

Does anyone now of good manufacturers of windows. Locally I can get a joiner to make me some but i dont know if it would be better to get them made by a bigger supplier. Im really after draftproofed (ok I know we are talking about sash and case!) long lasting windows.

They have to be sash and case and UPVC is definitely a no go. Its not that I have to its just that I hate them irational though it may be!

I dont know if it is worth going for hardwood or not and the whole thing about weights or springs just confuse me . Any advice.

Jw

Will external timber doors warp?

DrFrog — Fri, 11 Sep 2009 23:15:59 +0100

Hi,

I'm getting an extension built on the back of my house, which will have fully glazed french doors and a single fully glazed door. I'd like to have timber frames, and the architect has specified douglas fir, 65 mm thick frames, with 8+10+6 mm argon filled double glazing.

The builder/joiner swears that the timber will warp, whatever we do to protect it, leaving us with badly draughty doors, or continual maintenance, and thinks we should go for upvc. Is he right?

If I go for timber, is the spec a good one to go for (choice of douglas fir, for example)?

Many thanks in advance for any advice.

Pointing and rendering query,

StevieArgyll — Wed, 09 Sep 2009 12:05:54 +0100

Hi

I have just moved into a 1975 build 3 bedroom bungalow at some point the front will need re-rendering.
Its West Coast Scotland, near the sea, probably 800 yards, So its humid and very wet, torrential in fact at this time of year.

Its timber frame, cavity wall brick build. Its been cavity wall insulated.

At the moment there are a few cracks at the window corners which need immediate attention.

I was going to patch this up with ready mix mortar until I can get round to get it re-rendered. What is my best bet for re- rendering? Is lime Mortar suitable?

Thanks

thermally insulating solid masonry

spoonandfork — Fri, 31 Jul 2009 16:08:45 +0100

I'm planning on putting up interior walls to line a building which is brick and stone built, no cavity. I looked into using metal stud, ie Gyplyner universal / IWL, or Knauf etc which look great for ease and speed and straightness. But have been put off because I think a timber wall will conduct considerably less, offering greater insulation. I'd be interested to know if anyone has seen direct comparisons between 2 similar systems to see how much of an effect the metal is having?

Also I thought if I build my wall with CLS (38 x 63mm) I could do the following; if I turn the CLS uprights around so that their widest side faces out (the 63mm side) I could then fit 40mm phenolic between the upright studs (600 centres) but then also have enough room to glue 10mm phenolic on the back of the frame thereby covering almost all the stud. Although the 40mm would stick out beyond the stud by 2mm, I think this can be overcome with a strip of something to bulk out the CLS, or the board might be able to manage the slight bend. Or even 30mm could be used, and the following 10mm phenolic board would sandwich in an 8mm air gap, which wouldn't be a bad insulator at all. I wonder how all these systems compare. Anyone out there into thermal modelling and calculations?! has anyone seen anyone doing the CLS frame and gluing thing?

Skimming with lime plaster

alant — Thu, 27 Aug 2009 19:53:44 +0100

Me again.
I have used wood wool boards for a ceiling and have tried to use a finish plaster directly onto the boards as recommended by manufacturer. I have found that this has been very tricky due to the suction from the boards leaving the plaster" dry" in seconds. It goes on the walls fine but the ceiling is a bit of a mess at present.
Any tips / solutions?
Cheers
Alan

What's the worst that could happen?

pdurkan — Sun, 21 Jun 2009 21:11:26 +0100

Hi,

Just opened our chimney up, but might not get around to lining chimney & fitting register plate before winter. Chimney's been swept and tested, and is internal to the building - the stack is shared with our neighbour, so fairly insulated(?) I thought I might use a little 4kw stove anyway this winter, but am hearing lots of tooth sucking and tutting, but I wondered, over 1 winter, what's the worst that could happen?

Paul

Diameter of copper pipes in a Solar DHW system

DocB — Thu, 15 May 2008 19:31:31 +0100

I'm trying to understand how a solar DHW heating system is put together. One issue seems to be the size of copper pipe used in the circuit between the panel (or evacuated tube array) and the storage tank. I've seen 10mm and 15mm recommended. I wonder if anyone can shed some light (sorry) on this...

I don't have a system yet, but I do have some of the components. No solar collector yet, but I've got a thermal store with two coils (one for the solar panels and the other for the boiler). It'll be indirect in that a plate heat exchanger on the side will be used to heat up hot water for the taps. It won't provide any hot water to the radiators in the house. Not sure if any other info is required.

What I've heard so far is that 10mm pipes mean less circulating volume. Maybe a smaller circulating pump could be used, I don't know. I've also heard this means less heat loss. I don't really understand this because I thought heat loss was a function of surface to volume ratio. A 10mm pipe would have more surface to volume than a 15mm pipe so I would have thought it would lose MORE heat per unit length than a 15mm pipe.

Anyway, I'd appreciate any input from someone with more knowledge.

Cheers,

--------------- Doc

What's the deal with hempcrete?

wellburn — Mon, 02 Feb 2009 22:57:56 +0000

We have a solid walled listed georgian brick house which has been adapted many times in it's history.
Currently 40cm solid brick walls, - with stud & plasterboard liner with about 40mm unventilated void. Gypsom plaster & non breath paint.
External insulation is out.
Having read all the issues about internal insualtion/condensation etc I am attracted to this wonder product hempcrete but cannot find out anything.
If I remove modern internal additions and go back to breathable brick & lime can I just apply this help & lime product to my internal walls? - overpainting with nice breathable paint of course.....
Is it a DIY or do you get experts in with a big squirty splatter gun ?
What kind of thickness would I need to achieve building regs plus ?
I have studied the web site but don't get it, - or maybe am looking in the wrong place.
Is there a minimum wall area to justify ?
What sort of cost per m2 - I have maybe 100m2 of internal walls (or more) that I would like to insulate.
I am attracted to wavey flats and edges, - but how do you resolve edge detail, - and especially where it meets floor & ceiling joists.
Is it the wonder product, - or am i better off with internal stud/batton & slab insulation, - and all the risks that can carry?
Any experteese much appreciated.
Thanks
P