Green Building Forum - General

open vented wood burner

clynelish — Thu, 27 Sep 2007 18:54:57 +0100

Hi

I am hoping to fit a wood burning stove with a charging unit (laddomat 21) sending the heat to a 1500 litre accumulator, I am also going to be sending solar to this tank form an evacuated tube panel. My plumber is worried about "pump-over" in the vent pipe that rises off the hot (flow) side. Has anyone got a working installation like this ?

Thanks in anticipation

Warmcell installer in Cornwall?

sye — Thu, 04 Oct 2007 20:49:12 +0100

Anyone know of one?

ta

Green Building Magazine - London Stockists...

ben0v — Mon, 01 Oct 2007 09:30:12 +0100

Any ideas where I can buy a the latest edition in London?

Do a job you love...

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Screeding Over Underfloor Heating Pipes and Types of Insulation

EdF — Thu, 05 Jul 2007 12:42:52 +0100

About to lay 65mm of screed, but I'm a little confused how to mix it, wettish or dryish? I've seen both done (after the event). If it's fairly wet I expect it will be easier to put down and level. Should I put a retarder in it to help out, how about a plasticiser?
I discovered that 'almost everybody' in my area lays Kingspan or similar insulation under UFH. Apparently this is not ideal, extruded polystyrene is better, such as Dow Floormate or Knauf Standard Floorboard. The proprietor of the biggest UFH specialist in my area advised me and showed me samples. Kingspan etc is not so resistant to compression and can crumble, the two I've mentioned don't, he said. Probably better if there's a lot of big footed contractors going to walk all over it before it's screeded.. I found Sheffield Insulation were cheapest where I live, also Warrens in Chesterfield were not bad.

Copper, and a plumbing puzzle

Bluemoon — Thu, 27 Sep 2007 21:05:21 +0100

I'm a DIYer who does plumbing once in a blue moon. I ordered flexible tails to connect the bath filler, and the bidet mixer comes with them included. Here is the puzzle, why have I installed 22mm copper tube to feed the bath, when the bore of the tail is only 13mm? Similarly, the basin has 15mm pipes but the tails and mini valves have a bore of around 8mm. I wonder if the fittings had clear bores designed into them, we could all use smaller pipe? Or is it me? Copper is very expensive at present due partly to increased demand. Smaller pipe would use less metal, and be greener due to less energy used in production and carriage.

Rainwater harvesting trade off against drain requirements

richy — Sun, 30 Sep 2007 11:42:01 +0100

The 20 sqm cabin in the woods is to have little more elaborate than a water butt for rainwater harvesting and watering the garden, but the drainage requirments to keep BC happy are to be 2.5m cubic M soakaway. Can I reduce this by getting more serious about harvesting?

Shading to windows

tony — Fri, 28 Sep 2007 00:17:07 +0100

What angle of shading should be used for south facing windows.

Should a window be fully shaded by slats or a canopy/ verandah at mid day from June to the end of August or what and how?

combi hot water from thermal store solar and wood stove

martinlta — Fri, 28 Sep 2007 11:05:22 +0100

Hi

Is it possible to connect the output from a mains pressure hot water supply (Heated by a thermal store - solar + wood stove input with plate heat exchanger PX for the mains pressure side) to the input of a Puma combi gas boiler on the hot water side. The Puma manual states mains pressure cold water input, but if I turn down the hot water temperature output setting on the boiler to low (40-50C), and kept the mains pressure hot water input from the Thermal store PX to no more than 70C, would the combi not fire up until the temperature of out put dropped to <40C. The Combi has the std overheat stats in addition to the output hot water temp control stat.

Any thoughts

Metering of Low or Zero Carbon Technologies

Iain — Thu, 27 Sep 2007 09:24:07 +0100

I'm in the process of writing an article on the above topic and wondered if there was any anecdotes people on here would like to share?

On speaking to BMS providers I've found that they're more than capable to sub-meter mains supplies to circuits but less knowledgable about embedded supplies. Surely the performance of these technologies needs to be fed back into the design process to assist developers and planners select the best performing system?

Have you found installers to be poor in metering their systems? Are their systems easily integrated into larger building energy management software?

Any comment much appreciated.

Self Build Books

Iain — Thu, 27 Sep 2007 15:20:32 +0100

I've recently found out that I own part of a field in the north of Scotland. Being an industry professional I've always wanted to get my hands dirty and build my own house, my only problem being my lack of experience in small scale construction matters.

Can anyone recommend book that'd give me a crash course in the process? I'm well versed in my field there are gaps in my knowledge especially when it comes to choosing one construction method over another (e.g. double skinned brick with cavity versus timber framed).

Any help appreciated.

Also, has anyone built their own house and documented the process? I'd be very interested to read these. Again, many thanks. :smile:

Ridge Tiles

tony — Tue, 25 Sep 2007 16:34:05 +0100

It would be very interesting to know how many readers have had to have a ridge tile re-bedded onto the roof of their house. I suspect that many readers, some of whom live in quite new houses, have had ridge tiles blown off their roofs at some time during the past few years. Certainly it would be true to say that far too many ridge tiles have been coming adrift in recent years. Why is this? There are several reasons:-

One reason is that, in my view, all ridge tiles should positively mechanically fixed in addition to cement mortar or other bedding which is used. The majority of ridges are still put on roofs using mortar and although many specifications say â€˜fully bedâ€™ this is very rare to find. I feel that we should be using ridge tiles that weigh about twice as much as they do at present. It should be borne in mind that most Victorian ridge tiles havenâ€™t moved since the day they were laid despite the fact that the mortar under them has turned to dust.

We must therefore mechanically fix down ridge tiles in all locations in order to provide longevity to our roofs.

Beit and Braces examples of wastefull overkill

tony — Wed, 12 Sep 2007 08:27:10 +0100

In the days when we first started to use wire ropes for lifting loads we used to pass the rope through an eye or cleat and fix it back to itself with a wire rope grip (a u-bolt with a flange) The trailing free end of the rope would be tied onto the rope to keep it out of the way. This worked well but after a couple of mishaps where the u-bolts were not inspected and they either were damaged or worked loose through overloading it was decided to use two wire rope grips should be used in case one failed between inspections. No problems ever occurred but someone eventually decided that three would be better than two and this was common safe practice for many years. That was until some safety manager in an office saw a picture and thought that we should halve the risk by using SIX; this became law!

How much of this kind of thinking is wasteful of resources without adding benefit?

Should I fix very wet green oak rafters

oiseaux — Tue, 18 Sep 2007 02:43:50 +0100

Hello, I am slowly (very) constructing a garden room with a tiled roof using old oak for glazing and main frames, and green oak for the rafters. It appears to be extremely wet and I guess very new. I have read on this forum that green oak will shrink by 10% and I am concerned that my 3.5 metre long rafters will contract and take other frames with it. Should I leave the rafters in postion and covered but not fixed until they seem to have dried out. Your comments would be most appreciated.

New roads -- no more needed?

tony — Fri, 21 Sep 2007 14:59:24 +0100

Do we need ant more new roads?

Excavation on tricky site.

richy — Sun, 23 Sep 2007 19:18:36 +0100

I have a job coming up hand digging some foundations for a cabin at the top of a small hill in the woods. The 4 -5 cubic metres of earth which is removed will need to be taken away from site, there is no choice, the owner insists. Getting it to a skip will involve negotiating a wheel barrow over drystone walls and down bankings.

I just came up with an alternative idea; to rig up a zip wire or arial runway from a tree at the site down to some scaffolding sheer legs next to the skip and making a sort of hopper or scoop out of a plastic barrel. The idea being to fill the barrel by hand shovel and then let it wing it's way 30ft or so to the track where another line pulls it into the tip position just above the skip! Then it's gets hauled up by a line for the next load.

Sounds wacky and will cost about Â£100 in kit to try it, but it will have minimum impact on the surroundings compared to dumpers or tracked vehicles.

Will it work? Anyone any experience of anything similar? I'm hoping it will save a lot of really hard work!

constructing a cellar

howdytom — Thu, 20 Sep 2007 19:45:00 +0100

I want to include a cellar in a barn conversion project, but whats the best construction.
It would be nice not to use concrete, my subsoil is mainly boulder clay 16foot on limestone. The site is fairly level so digging a drain would be impossable unless I go 300 meters !. I used to live in an old house with cellars it had limestone walls but I have no idea what they used behind as a water barrier... maybe nothing. If I dug it out cast a concrete floor with DPC , built limestone walls, what would be best for the roof ?. I would hope to end up with an internal size of 3meters by 5meters:confused:

Why inward opening doors?

Henry Sears — Thu, 06 Sep 2007 22:36:36 +0100

Not exactly a green building issue, but I think this forum's got some intelligent heads participating, so here goes.

I'm renovating a timber house at the moment, and two external door frames need replacing, having rotted out at the bottom due to water getting into the joints at the bottom of the frame.

It would seem to me to offer several advantages to hang external doors to open outwards (although i can see the difficulties when they're at the top of flights of steps).

Weather sealing would be more easily achieved, and the bottom cill could have a nice flashing that stood up behind the bottom of the door. Also the door wouldn't encroach on indoor space when opened.

And bailiffs would find it much harder to force entry!

So why do Brits always hang 'em to open in?

Past the magic 1000 barrier

GBP-Keith — Thu, 20 Sep 2007 19:39:43 +0100

I would like to say a big thank you to all who have joined the green building forum and have made it such a great place to discuss our pet subjects.

Now we have over 1000 members, we really do have a green building community that is happy to share, discuss and promote our ideas. Well done to everyone.

Lost in Transmission

biffvernon — Wed, 19 Sep 2007 21:28:32 +0100

Lost in Transmission is a report just published by the Sustainable Development Commission concerning the future organization of our energy supply industry. Perhaps tangential to Green Building, but with 46% of UK CO2 emissions coming from buildings, it's an important document for anyone with an interest in the energy use in buildings. The matter of household generation and grid tie up is particularly addressed.

http://www.sd-commission.org.uk/pages/ofgemreview.html

http://www.sd-commission.org.uk/publications/downloads/SDC_ofgem_report.pdf

wood burning

ciderman — Tue, 14 Aug 2007 22:09:24 +0100

i feel that there are a lot of eco warriors who would have us all wearing rabbit skins and living off grass, and, at at ambient temperatures. come on, think a little, manage your own environment and look to your neighbours.
we can others can't. work from home- reduce your mileage-take a drop in salary. sadly, most will not do that.
oh dear , i could go on........

Zero carbon versus carbon neutral

fostertom — Thu, 13 Sep 2007 15:20:27 +0100

Cosy racket:
"I think there is some confusion amongst the public about the difference between 'carbon neutral' and 'zero carbon'." continues John ...............
http://i30.photobucket.com/albums/c301/fostertom/Millwoodcarbon-neutral.jpg
"To achieve carbon neutral status, all Coppice Mews homes will be assessed by The Carbon Neutral Company to determine their carbon footprint. Investment in sustainable projects, such as wind farms, will then offset their annual carbon emissions. MilIwood Homes will ensure that construction is carbon neutral and will then buy â€˜carbon creditsâ€™ for the first year after the buyer moves in, offering purchasers the option to carry on the good work for life."

Should we all live in Travel Lodges?

tony — Fri, 14 Sep 2007 12:52:59 +0100

It is a clear winner on cost grounds! but what about in green terms? Do the pluses outweigh the minuses?

Belt and Braces -- examples of wastefulness

tony — Sun, 16 Sep 2007 09:22:22 +0100

Sorry guys I messed up the Title line of this one so am repeating it

Tony said,
In the days when we first started to use wire ropes for lifting loads we used to pass the rope through an eye or cleat and fix it back to itself with a wire rope grip (a u-bolt with a flange) The trailing free end of the rope would be tied onto the rope to keep it out of the way. This worked well but after a couple of mishaps where the u-bolts were not inspected and they either were damaged or worked loose through overloading it was decided to use two wire rope grips should be used in case one failed between inspections. No problems ever occurred but someone eventually decided that three would be better than two and this was common safe practice for many years. That was until some safety manager in an office saw a picture and thought that we should halve the risk by using SIX; this became law!

How much of this kind of thinking is wasteful of resources without adding benefit?
____________________________________________________________________________________________
Rimu Homes replied,
Loads and loads and loads,

I just got off the phone with our engineer to tell him we can't source C24 219 x 44 at short notice, in the lengths he specified for a project. I asked if we can use 219 x 38 instead and he said that would be fine. I can't remember how many times I have had similar conversations over the years. Usually with engineers.

The term 'over-engineered' is a pet hate of mine as engineering is about accuracy. In my opinion if an engineer feels he has to over specify he should consider a different career.
The culture of over ordering of materials is another pet hate.
_____________________________________________________________________________
biff came in with:

3

Mathematician: the integer greater than 2 and less than 4

Physicist: a value greater than 2.5 and less than or equal to 3.5

Engineer: three's three but we'll call it ten to be on the safe side.
__________________________________________________________________________________________--
Chris Wardle quoted
I'm afraid it is a sign if times. Everyone is so worried about getting sued that they err on the side of caution every time.

What I think engineers, building inspectors etc overlook is the fact that the manufacturers and the people who write the standards that we all work to have already allowed for a margin of safety so there is no need to add your own on top.

As for the Health and Safety fascists, with that lot it is all about having a piece of paper to say you have considered the risks etc. They never check whether policies are being implemented until someone comes a cropper, then the finger pointing starts and new legislation follows.

I'd like to live in a country where you are allowed to take a few risks and you live with the consequences of your actions. Make all these regulations into guidance that you can choose to follow or not. Most people do the right thing anyway, unless the "right thing" is an affront to common sense, and those that don't ignore regulations in any case. They serve no purpose other than to reduce the productivity of the economy.

Fascinating history of the Vapour Barrier + construction idea

tomsusweb — Sun, 02 Sep 2007 20:53:10 +0100

I just found this very interesting article:

http://www.housebuildersupdate.co.uk/2007/07/little-known-history-of-vapour-barrier.html

I'd be interested in forum members thoughts - especially as there still seems to be a lot of debate on this forum about breathing wall timber frame construction as described in the Whole House Book and advocated by Warmcel. (e.g. see here: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=532&page=2 )

I'm about to embark on a self funded new build in Ireland. Building control and codes are a non-issue for me, so I'm contemplating something radical. A timber frame house with electric fan assisted passive stack ventilation to remove moisture laden air from all rooms. Wall construction (inside to out): sasmox boards on 6x2 studs with sheeps wool insulation, then 100mm tektalan e21 magnesite wood wool insulation boards and then a render of waterproof rein fibre cement on a mesh (rein fibres and mesh will prevent cracking).

Conventional wisdom says this is madness.

My logic suggests that it will be super insulated, the studs will be warm - hence no due point on them, and internal most moisture will be moved by the ventilation. Obviously I will need to carefully keep an eye on the rein fibre render, but unless water is pouring in from the outside, the timber is 100mm away and should be safe. The advantages of taking this route are simplicity, cost effectiveness and super insulation. The danger according to conventional wisdom is that the timber will rot. I don't think it will.

More info on tektalan insulation boards is here:

http://www.skanda-uk.com/heraklithProducts.htm

More info on Rein fibre cement which I have used in a 7mm coat to create waterproof bird baths that haven't cracked in years:

http://www.koicymru.co.uk/const9c.htm

http://koicymru.co.uk/q&a7.htm

I'm almost tempted to try the construction as an experiment. The thoughts of the forum are very welcome!

(This is my first post - I've been a long time lurker - many thanks for all the insights on the forums.)

A Life Without Renewables

Neil Adam Hall — Mon, 10 Sep 2007 15:16:28 +0100

I am a little apprehensive with regard to renewable energy technologies, the first step in housing design surely is to: a) reduce the need for energy and b) to use energy more efficiently in the building; before energy is to be supplied from renewable sources.

Cyril Sweett's 'Cost Review of the Code for Sustainable Homes' tells us that CSH minimum performance standard for energy efficiency at Level 3 is achievable [under certain dwelling types] without the need to integrate renewable energy technology into house design. However there is the need to integrate WHMVS into the design.

Assume a property were to be built which would not be affected by the Merton Rule or FALP, etc... and therefore would not require renewable energy technologies to displace a % of the dwellings CO2 emission rating.

Is it practical to expect a building to meet CSH Level 3 energy efficiency standard without the need to integrate renewable energy technologies into the building design? What U-values [walls, floor, roof and windows] and level of air tightness would be required in order to achieve this?

And is achieving CSH Level 3 energy efficiency standard without renewables a cost effective option? Or should we forget thermal efficiency and install oversized boimass boiler's in every house to meet these Code requirements?

Hazardous waste --------- plasterboard!!

tony — Fri, 07 Sep 2007 12:53:21 +0100

A local builder put a couple of naff half sheets of plasterboard on a waste skip. When it came to paying for the skip the 'wasters' charged him for the skip that he had plus another one to put the plasterboard in!!!! ie double !! Gypsum is dug out of the ground and squashed between paper.

Can anyone throw any light on why it could be considered a problem? ( I know we don't like plasterboard but it is pretty difficult for builders to avoid)

Your ideas for my new build in the Scottish Highlands

tomlin — Wed, 29 Aug 2007 19:11:20 +0100

Hi, I'm new to self build and Im in the early stages of planning a new build in the highlands.
Standard construction around here seems to be 100mm concrete block exterior with render, 50mm cavity and 150mm timber frame. Recent builds seem to have used 150mm frametherm insulation in the walls covered with foil backed plasterboard. I intend to build into the roofspace with attic trusses but have no idea how this would be best insulated.
I would like to incorporate a ground source heat pump if it falls within our budget, otherwise oil seems to be the next (but not very geen) alternative. No idea yet about windows/doors.

My question is ; Which area should I concentrate on to improve energy conservation - ie where will I get the best returns on investment ? Insulation, window/door spec/other ??

Thanks

Wood burner stove connecting to oil combi boiler

MALCOLM — Tue, 11 Sep 2007 18:45:09 +0100

please help, i have read, i feel most of the discussions about wood burning stoves

what i have is a sealed combi oil boiler (worcester 15/19) and a wood burning stove 12000 btu with back boiler (not connected at present)
14 rads over three floors connected on the main pipeing 22mm and rad fed on 15mm.
i was going to link the stove to the flow and return, using all the rads as heat leaks. some say no pump
others say a bridge pipe with the pump and a pipe stat so if the power go it wont blow up
as i feel when the stove is in full temp it still wont heat all rads but will help the oil
boiler and save fuel.

what am i missing or is it the simple
many thanks

Heating for new build

John Clark — Fri, 07 Sep 2007 21:48:43 +0100

Hi all,

This is a very useful site, I've been reading it and getting ideas for some time, but I think it's time to ask directly for some assistance.

We're building a new timber frame house of about 150 sq m, it will be insulated to well above current requirements. We originally wanted ground source with underfloor heating but have been worried by conflicting advice given to us, and also think we'd have trouble installing it on our land which has quite a few trees, as well as being solid chalk a couple of feet down.

Air source was tempting for a short while but I don't like the noise factor, the large outside unit, the way it stops working if the temperature ever gets really cold.

My plan was then to install the underfloor but not connect it yet (maybe wait for air source heating to improve?). We'd have a couple of wood burning stoves, one with a back boiler to provide DHW, backed up by off peak immersion heater.

I then read about pellet stoves with back boilers and we're wondering whether this would be a better option. However we don't know anyone with pellet boilers/stoves and are concerned that it may be expensive to run, inflexible and also expensive to install. And who knows whether we'd even need it - in a well insulated house would the 2 stoves be sufficient?

Would this option work with underfloor heating? If so would we need a thermal store or something??

Trying to get information on these things is really difficult; it seems like we'd be pioneers if we used this technology. Or possibly idiots.

Any help, input etc would be most welcome from you experts out there.

Thanks,
John

Cyprus

tony — Wed, 08 Aug 2007 16:55:50 +0100

At first glance seemed a greenies paradise. Solar hot water on almost every building.

Then I realised that no one insulated anything! never saw any insulation at all! Yet there were huge output radiators in rooms in the mountains (snow in winter).

Almost everyone had air cooling and yet no insulation. They did used to design for solar shading but not so much for new stuff.

No recycling. Plenty of litter and rubbish around.

The amounts of insulation we put it it was quite a culture shock to see none being used.

Oh yea and pretty much no planning control the whole place was just one big building site -- everyone seemed to a property developer. ( one was claiming green!!)

Energy Saving Lightbulbs Quality

moogaloo — Fri, 07 Sep 2007 16:28:13 +0100

I have traditional compact flouresent Energy Saving Lightbulbs in all my light fittings, except for the bathroom where I have some GU10 LEDs.

Now most of my lightbulbs are Bayonette pound-a-pop phillips variety (EST subsidised) from an online retailer. They come on to full brightness very quicky and are nearly comparible to the incadesent equivenlants.

I have a couple of small candles which are also fine and a daylight spiral bulb which is also fine.

However I have bought some GU10 and R50 CFLs and they where expenisve and are rubbish. If left for five minutes the light you get from them is fine, but they take 5 mins to warm up and the initial light is very dark.

How come some CFLs are so rubbish? I think people have the impression that CFLs are inferiour to incadesents and are therefore staying away?

Is there anyway I can find out which ones are the good ones?

How to insulate and damp proof a shed?

nat — Fri, 07 Sep 2007 19:51:01 +0100

Hi there,
I have just joined the forum and I am a novice DIYer.
I have a new summerhouse I want to use as my art studio. I need advice on how to insulate and dampproof it so that I can use it (almost?) all year round.
I have been told to use either polysterene or Celotex as insulating material.
In your experience what is best? Is there a big difference in heat retention?
For dampproofing, do I lay the damp proof sheet before the insulating material or after?
I am planning to cover the walls with tongue and groove cladding afterwards.

For the floor. any advice of what type of insulating material to use and "recipe" on how to do it (what order, how not to crush the layer of insulating material when one walks on it, etc...)?

A professional electrician will put power and lights in there, I am not that daring....

Thanks for any advice that will be very appreciated.

Nat

Problem clients?

betty_tv — Fri, 07 Sep 2007 12:47:13 +0100

Hello all

I am working on a new Channel 4 documentary series which explores the relationship between builders and their clients with the working title ''Dont Blame the Builder''. I have permission from the team to post on this forum and was wondering if anyone would like to get in touch regarding involvement in our programme?

The series is about the problems that can often arise on domestic building projects as a result of a breakdown of communication between clients and their builders. This is a common problem and can prove a real nightmare for both parties concerned. Unfortunately people are always blaming the builders but can it always be their fault? What about clients who have unrealistic demands, constantly change their minds or just canâ€™t make a decision and donâ€™t take your advice?

Weâ€™re looking for builders who are experiencing a breakdown in communication with the client on a current project and need some help to get it back on track. We will offer the services (for free) of an industry expert to work with the homeowners and the builders to help resolve any problems. The programme is a great opportunity to reach an amicable solution that gets everything running smoothly again for all concerned. The first two episodes reached a successful conclusion for both parties concerned and I am confident that we can achieve the same result the third time around.

If you are locked in a stand off with a client or are finding it difficult to cope with their constantly changing demands please contact me for an informal chat or email me details.

Fiona 0207 907 0869 or fiona.wilson@betty.co.uk

Sealing fireplace hearth (cob/concrete)

cornishben — Wed, 05 Sep 2007 09:42:15 +0100

Hi,
We've recently excavated an old stone/cob fireplace in our cottage which was hiding behind a thick 1960s concrete eyesore.. As it's an old cottage it doesn't have any kind of DPC and the construction is granite/earth on the lower half and cob on the upper half.

Hence, the backs/sides of the fireplace are granite/earth, which I have lime rendered. The hearth base was just earth/stone, which I have (perhaps not wisely) laid a 2-3inch concrete bed on.

We are now looking to lay some slate on this concrete but the concrete is damp and there seems to be dampness creeping up the plaster at the back/sides, up to 4-5inches high. I guess this is because basically its just earth underneath..

I'm wondering what I can do about this?!

Could I bitumen or damp proof the concrete base somehow, before laying the slates. Which may resolve the problem of a damp base, but if so, would i need to cut into the base of the sides to insert the DPC or something in order to stop the dampness rising up the sides?

Site consumables

Jillf — Thu, 06 Sep 2007 14:54:53 +0100

Hi there

I am currently seeking out site consumables that are eco friendly
I have done some searches but to little avail

looking for

cables ties - made of recycled plastic or eco equiv
latex gloves or equiv
Gaffer tape

many thanks for your help

best J

Insulating Suspended Timber Floor, ready for UFH

sweevo — Wed, 29 Aug 2007 23:08:18 +0100

Hi,

we're (hopefully) soon to have some renovation work start on our home. As part of the work all rooms that are involved will have the floor insulated (100mm K3 Kooltherm) and UFH (Polyplumb overlay) installed. The work does not include the kitchen however which is where the condensing combi boiler is situated.

Our plan was always to rip out the old kitchen (already in place when I moved in 8 years ago) and replace with a new one of our own choice and use this as an ideal time to install the UFH along with the manifold etc in there first. At the moment the floor in there (suspended timber) is not insulated so i'm planning on doing this part of the work myself, ie prior to UFH installation. I'd looked into how to do this about 12-18 months but just wanted to run my plan of action by people who are far more experienced when it comes to this kind of thing.

First up, the K3 Kooltherm is expensive and with the boards being 600mm wide there will be a lot of wastage, ie joists are approx 370mm apart. I was told I couldn't glue spare pieces together to make a new one so I figured i'd be throwing 1/3 of the stuff away which seemed like an awful waste. Because of this I looked at Space Blanket as an alternative. The 200mm rolls have an R Value of 4.5mK/w which if I understand the sums correctly would equate to a U value of 0.22 which is what is specified in the building spec for the 100mm K3 Kooltherm. So in effect I get the same level of insulation for far less cost. One thing that I also wondered about was which way to face the silver coated side of the space blanket. In my loft it faces up so I imagine it would be the reverse under my floor, ie facing down to the ground. Anyone know if this matters either way?

So..... I remember reading about suspending the insulation with netting (nailed to the underside of the joists as support) but have heard that this can sag and reduce the effectiveness of the insulation. With this in mind I wondered if there was any reason I couldn't use the more rigid plastic type fencing (usually green) you get in a roll from garden centers etc to prevent any sagging? I was thinking that wouldn't sag at all if firmly secured to the underside of the joists meaning the 200mm of roll would be slightly compressed into the 175mm joists height and hence touch the floor surface above it.

Finally the UFH install guide says to install the damp proof membrane on top of the flooring prior to laying the overlay boards and piping. I think some people have put this membrane below the floorboards and above the insulation. Would having this membrane over the floorboards rather than under it cause any longterm problems with damp/condensation or do I even need to do both?

Thanks in advance......

Inappropriate prize?

Bluemoon — Wed, 05 Sep 2007 10:34:27 +0100

I've just received the latest issue of Installer's Choice from Worcester Bosch Group. On page 6, a competition for the 2008 Green Earth calendar. The prize is: a holiday in Miami, presumably via a kerosene-burning jet aeroplane! A greener prize could have been chosen?

Worried! Timber shortage!

richy — Sun, 15 Jul 2007 10:37:46 +0100

Timber has risen 20% in price this year here in Yorkshire and prices are set to continue to rise.

Personally I hate those Larch Lap fencing panels, but some of my customers want them, but there is a national shortage of them! I thought it might be due to the storms earlier this year but I am told it is because China is buying up much of the Worlds timber due to the rapid development of that country, and this is forcing the prices up. One big fencing panel manufacturer near me has had to lay off most of his men due to not being able to secure timber supplies!

This is a worrying development, I hope some serious thought will be given to producing more and better home grown timber! It might be already too late for the next generation of Carpenters.

Ventilation and breathability - healthy buildings

Peter Clark — Tue, 04 Sep 2007 12:47:29 +0100

Hi,
I just came across this very striking article 'Breathability: The Key to Building Performance' on this webpage

http://www.naturalinsulation.co.uk/downloads.aspx?lc=English&pt=h

It seems very interesting to me although I do not know anything about the author, Neil May, is or his relationship to the natural insulation company.

Amongst other things he is recommending moisture control by hydroscopic buffering and he is looking again at active ventilation, AND passive ventilation.

Modern timber frame and roof construction may be a 'nightmare'!

At the end he has 4 principles of design.

Very interesting reading for me, although I know many people here will be very aware of all this.

Does anyone have an opinion? (ducks)

Peter

Weather compensated heating control

royer — Fri, 31 Aug 2007 09:30:15 +0100

Have read various earlier comments re weather compensated heating control for which Honeywell Aquatrol 2000 was considered ideal, but apparently discontinued. Honeywell just said its new 'Smile' controller is Aquatrol replacement: responds to outside temperatures and boasts pre-loaded basic programs to reduce planning and start-up effort, see www.smile-control.com
PS. Up to five Smile controllers can be wired together via a two-wire bus to form a control system

Gas cookers and airtight houses

1not24get — Sun, 26 Aug 2007 20:00:48 +0100

Just wondering are there any experts who might be able to shed some light on this topicâ€¦..I will be building an airtight house (airtight to passive house spec <0.6 ach/hour at test pressure) but the Mrs loves cooking using a gas hob. Iâ€™ve done some reading on the internet and the main concern with using gas in any house is the accumulation of combustion gases (nitrogen dioxide and carbon monoxide). Studies done to date indicate that in many â€˜housesâ€™, levels of these gases exceed WHO safety levels. I suspect these studies were carried out on â€˜traditional buildâ€™ homes and not airtight ones. My question is if I were to use a gas hob in an airtight house with MHRV would this be dangerous? It seems as soon as â€˜airtightâ€™ is mentioned people freak out at the thought of using gas when it seems before nobody ever paid much heed to combustion gases when building a traditional house. Would the MHRV make the house safer than a â€˜traditional build houseâ€™ because with MHVR the air exchange is continual and not irregular or variable as with traditional build houses??

Kingspan at BRE really zero carbon?

Peter A — Tue, 28 Aug 2007 19:37:01 +0100

With a big publicity fanfare a zero carbon home was unveiled at the BRE. I wonder how much publicity will be given to it's re-assessment and that it might only be somewhere between levels 4 and 5 of the code? No mean achievement but not level 6!

Merton rule

biffvernon — Mon, 20 Aug 2007 15:44:18 +0100

"The Department for Communities and Local Government is to in effect abolish the so-called "Merton rule", under pressure from housebuilders who do not want to bear the cost of adding things like solar panels to the buildings they construct or the effort of marketing them as "green"."

The rest: http://www.guardian.co.uk/environment/2007/aug/20/energy?gusrc=rss&feed=19

Eco-village wins planning battle

biffvernon — Sat, 25 Aug 2007 23:24:08 +0100

The Landmatters co-op has won the right to stay on land in south Devon for another three years. more: http://news.bbc.co.uk/1/hi/england/devon/6962759.stm

Can gas flue bricks be used as a flue for a clean wood burner?

frostystart — Mon, 27 Aug 2007 14:43:18 +0100

HI I am moving to a semi detached house that has a gas fire on the party wall so i assume it uses flue bricks, does anyone know if the new generation of cleaner wood burning stoves can vent into gas flue bricks??

Thanks Colin

Rubble trench wedded to Frost protected shallow foundation?

anerdoo — Sun, 26 Aug 2007 19:49:46 +0100

As the budget for our new home seems to be growing exponentially, I would like to consider rubble trench foundation as an option. Can this design be hybridized as a frost protected shallow foundation (I live in eastern Canada) if the rubble trench is insulated on the exterior and with horizontally slanted 'wings'? The house plan is 24x32.

Concrete actually seems to require less of that money stuff when compared to the cost of delivered 2-4" stone, enough to fill a 20" wide wall. To build straw bale. In either case the assistance of our friendly neighbourhood heavy equipment operator will be required.

Hot Air Curtains in shops

Neil K — Wed, 22 Aug 2007 22:15:21 +0100

I am looking for some evidence of a definitive study into the effect of these damn things.

After remonstrating with a number of shops along the lines of 'Why have you got your heating/air conditioning on AND your doors open?' I got fed up with the usual range of reasons (see below) and took it up through the political route. This produced some rather worrying replies.

Remarkably the (un)informed view was that these are more efficient at keeping buildings warm than a door. Apparently it is believed they 'pressurise the building with warm air and stop it leaking out'.... and several other pages of complete nonsense along these lines. :cry:

Even the Energy Saving Trust stated that 'warm air curtains .. are an effective way of reducing heat loss' and that they are 'very effective at preventing the warm air inside the building escaping.' I was therefore wondering if anybody had any proof one way or the other?

Whilst I can accept that an air curtain can reduce convection of hot air through a doorway and can have an effect on preventing stratification of air flow in the doorway (i.e hot air leaking out over a stream of cold air flowing in) I doubt that the air curtain is as effective as an insulated door which was the point I was making.

I do find it difficult to believe that at least part of the heat being thrown down by the curtain is not going directly out the door. Has anybody done an independent study into this by checking temperatures around the outside of these doors?

If they are right we could stop putting up insulated houses and simply live under a canopy, put some fan heaters on poles and live in the balmy interior so created.... or maybe someone has the wrong end of the stick.

Glad of any pointers on work done so far.

Reasons for doors being open and heating/cooling systems attempting to heat/cool the rest of the planet:
> It is company policy to have the doors open
> It is so our customers know we are open. (Other than it being opening hours, the lights being on and there being people wandering about inside one assumes)
> Our customers like it
> So that disabled people can get in
> People find the doors hard to open
> The cold air from the shop helps with global warming (Give me strength!)

.... is it just me?

Flagship visit

tony — Wed, 22 Aug 2007 10:44:55 +0100

I recently visited the headquarters of one of our flagship building organisations.

I was horrified as it was summer and the heating was blasting away and all the doors were open! ----- wasteful or what?

The toilet facilities all had buckets under them to catch the drips.

There was a disconnected gas pipe with no cap on it in full view and a tap near by to turn it on.

No recycling bins just throw it all away.

No evidence at all of anything green, ecologically friendly or and not that much evidence of good building practice.

Is this place a Flagship or ship about to sink? If that is the flagship what hope for the rest of what gets built?

Suitable sealant materials.

Rimu Homes — Wed, 22 Aug 2007 15:33:29 +0100

Hi,

In another thread the issue of sealants came up but was not fully discussed. In our homes we use Sikaflex 552, http://www.sikaindustry.com/tds-ipd-sf552-us.pdf.

We try to use sustainable products where possible ,but I hadn't given much thougtht to the properties of the sealants. Is this stuff good/bad or are there other products I should be looking at in relation to green cred.
Hope the are some chemists ot there?