Wed, 10 Jun 2026 02:51:57 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5338 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5338 Fri, 12 Feb 2010 10:01:07 +0000 stephendv
Secondly, Warmcel seems to be OK to use in a cavity between 2 masonry walls - but on another product's page (Isofloc) they say that it's not suitable for a masonry cavity with no air gap:
http://isofloc.com/isofloc-l-light-weight-cellulose-insulation.phtml

Any ideas?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5490 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5490 Fri, 12 Mar 2010 14:21:38 +0000 ali.gill Properties will be monitored by BRE in-use once the properties are sold.
http://www.aimc4.com/
http://www.aimc4.com/page.jsp?id=1

Scotland's AIMC4 homes on the way_Sept.2011
http://www.building4change.com/page.jsp?id=951]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2043 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2043 Tue, 01 Jul 2008 15:52:44 +0100 ludite https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1278 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1278 Thu, 21 Feb 2008 16:16:25 +0000 nr8861
This is all new to me.

We are about to start the foundations on our new build timber frame and are looking at various window options. We were at the Self Build show at the weekend and saw aluclad windows and are quite interested in them.

Does anyone have these windows in their home or have any information on whether they are any good and if the internal wood is stained, whether it has yellowed or discoloured?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5385 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5385 Mon, 22 Feb 2010 12:04:49 +0000 owlman
Mike]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5165 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5165 Tue, 12 Jan 2010 12:26:35 +0000 wastetech DEWATS would mean that each house, or group of houses would have its own sewage treatment plant. The only effluent leaving every house would be clean water and the risk of major pollution incidents would be completely avoided.
DEWATS is being promoted all over the World - apart from the UK.
As much of the river pollution is caused by failing centralised sewage works and almost 80% of the cost of sewage works is in the pipework to transport it to a centralised location, is DEWATS a good or bad ideology?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2640 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2640 Wed, 01 Oct 2008 20:03:50 +0100 suomi
But any way here is the question. My parents have now replaced all their normal lighting bulds with CFT (is that the right term ?), expect the ones in the bathroom and the stairs. Main problem is that the bulds need to be 100watts and need to come on straight away. The CFT's seem to take a couple of minutes to get to full brightness, and I have not seen any that are equal to 100W.

I was wondering if there is a direct LED replacement for the normal bernet type incandescent? the only one that I have seen so far was for 40W screw type for a 120V US system.

Thanks for any help.:bigsmile:]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5284 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5284 Tue, 02 Feb 2010 16:54:49 +0000 Mike George
Thanks in advance]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5239 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5239 Sun, 24 Jan 2010 13:28:59 +0000 Ev
http://baavet.posterous.com/the-truth-about-the-baavet]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5101 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5101 Wed, 30 Dec 2009 20:18:29 +0000 RobinB
I have another area which will have a 18mm wood floor laid over. I was thinking of waiting a few months and sticking it down- as the wood-flooring people suggest, however I've also been told it would be better to put down a DPM and float it over that and not worry about it drying out. I also saw cwatters suggesting a dry forumula for the screed - any idea on relative cost of wet and dry screed.

All screed will have a low level of UFH.

Sorry if this is a "how long is a piece of string" question, and thanks for any answers!

RobinB]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5126 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5126 Tue, 05 Jan 2010 20:43:26 +0000 DarylP
Having fitted water saving aerators on to the taps, the flow rate is so low now that the flow switch in the WB combi boiler does not 'sense' water flow, and so does not fire....
Has anyone fitted/used this type of aerator, with a flow rate of around 3 litres per min @ 3 Bar.

Thanks in advance.......:smile:]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5085 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5085 Sun, 27 Dec 2009 08:55:53 +0000 Mike George
Needs to be available in 2400mm x 1200mm sheets. Interested in hearing about any type of rigid insulation but obviously this would mean being even thicker to achieve same u-value.

I don't want 'layers' of thinner stuff.

Any help much appreciated]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4932 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4932 Sat, 28 Nov 2009 13:54:30 +0000 Mike George
"If we do say so ourselves, our glass is a technological miracle."

Is it?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4959 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4959 Fri, 04 Dec 2009 08:05:02 +0000 Mike George
No doubt many insulations can be manufactured as thick as required but is there a way to bond them together on-site in the same way mortar is used between blockwork? I'm thinking particularly of the rigid high performing insulations.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4939 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4939 Mon, 30 Nov 2009 12:48:23 +0000 CWatters https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4927 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4927 Fri, 27 Nov 2009 16:12:41 +0000 tomhillonline
I'm trying to draw together a piece of research for some Housing Associations that details the different types of insulation options available. Pricing is one of the aspects that I'd like to consider but I'm struggling to find a simple way of sourcing/illustrating the price related information. I know its a complicated area but ideally I'd like to be able to present something along the lines of ' 100mm of rockwool mineral wool insulation has an R-Value of 2.5 and costs approximately £3.50 per sq meter'. Does anyone have any ideas about the best ways to do this and where I could go for information.

Thanks for any help.

Tom

p.s. one of the problems that I'm having is that since different insulations are used in different and each one has different thermal conductivities its quite hard benchmarking them against each other.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4917 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4917 Wed, 25 Nov 2009 16:41:19 +0000 Jordi https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3804 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3804 Fri, 27 Mar 2009 14:00:28 +0000 RobinB
http://www.energyenv.co.uk/PowerSaver.asp

"The EPS Power Saver uses a combination of filtration and correction techniques to improve the efficiency of various appliances and circuits. In addition, the intelligent technology optimises the voltage and current demands thus reducing the active power / KWH demands and achieves around 10% to 20% savings on your electricity bill."]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4860 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4860 Mon, 16 Nov 2009 14:14:18 +0000 CarneyC
http://www.knaufinsulation.co.uk/great_british_refurb_-_manches.aspx

It's not immediatley obvious but the battens on the wall appear to be XPS with OSB laminated on to them.

Interesting approach to mitigating thermal bridges. Can't seem to find information on them anywhere.

Chris]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3116 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3116 Wed, 10 Dec 2008 15:13:52 +0000 James Norton
Whichever one it is I seem to be getting wildly different cost estimates, anything from a couple of £k to £10k...! Can someone please point me in the general direction of a product that does what it says on the tin...?

(ie the tins says it recovers more heat than it loses and its not too noisy and doesn't breakdown much..)

J]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4689 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4689 Fri, 16 Oct 2009 16:50:04 +0100 Maria CEA
Maria]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4743 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4743 Mon, 26 Oct 2009 10:18:09 +0000 ecold https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4709 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4709 Wed, 21 Oct 2009 16:57:21 +0100 David Olivier
One user (Herefordshire) has had the plastic hinge caps perish since the windows were installed only 9 years ago. The innards of the hinge are left exposed. Not good. I've volunteered to ask on his behalf on a few forums whether anyone else has had this problem.

The SWC doesn't answer its phone and appears to be totally out of business. The ex-MD's father still operates a company next door (making precast concrete floors). I've no idea if he'd feel under a moral obligation to help.

David]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4683 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4683 Wed, 14 Oct 2009 19:42:22 +0100 tomhillonline
I've been asked to take a look at this product for someone and wondered whether I could get some of you guy's thoughts on it.

Wallrock is a 3mm thick foam/fibre glass wall covering made in Germany by a company called Erfurt (http://www.erfurt.com/cms/products/diy/klimatec-thermovlies.html - if you click the flag symbol in the corner it translates it to English). Erfurt do not describe it as an insulating wallpaper but it essentially works on a similar principle. I've read the forums thoughts on insulating wallpapers and have found them very useful. Laying aside the real world in practice savings I've got a theoretical physics related question that I'd appreciate some help with ...

Looking at this website (http://thenauhaus.com/blog/index.php/2009/04/the-problem-with-mass/) then it is apparent that a solid wall with Wallrock on it will feel warmer *to the touch* than a solid wall without it (inasmuch as a carpet *feels* warmer than a tiled floor).

However, I'm wondering whether this translates to when your 1m away from the wall not touching it? If we make the assumption that the temperature in the room is constant (at say 18'C) then I assume that the *real* temperature at the walls (as measured by a standard thermometer) should also be constant? (However, as was discussed above because the effusivity of Wallrock is different it will *feel* warmer when you touch it)

It appears that one of the most important factors of thermal comfort is Mean Radiant Temperature (http://dt.fme.vutbr.cz/enviro/Pohoda/thermal.htm). On the basis that Mean Radiant Temperature is a function of temperature difference between two bodies multiplied by their ability to emit and absorb heat (http://squ1.org/wiki/Mean_Radiant_Temperature) then in theory the Wallrocked room should feel warmer; both walls will be the same *real* temperature but the low effusivity of the Wallrocked wall means that (where a wall is cooler than a person) it will absorb less heat from an occupant than the non-Wallrocked wall.

Is my logic correct in this? Or does the fact that the two walls have the same *real* temperature mean that the MRT is the same in both circumstances (so ignoring the different effusivity)? Again, I'm more concerned with the theoretically possible aspect than the real energy savings at the moment ...

Any help would be greatly appreciated.

Cheers,

Tom

Note: I suspect that using Wallrock would *slightly* change the heating profile of the room (it would warm up slightly quicker than a non-wallrocked room because it effectively creates a barrier between the warm air and the cold wall). However, once the heat has penetrated the foam it shouldn't make any difference at all.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4633 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4633 Mon, 05 Oct 2009 18:28:18 +0100 mitchino https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4574 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4574 Mon, 21 Sep 2009 13:20:26 +0100 Pingy
The reason I'm asking is that I want to install a post midaway along an area of triple glazing to provide support and prevent flexing. As I'm using triple glazed windows with insulated frames I don't want to create a cold bridge by installing a solid 150mm square timber post.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4577 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4577 Mon, 21 Sep 2009 21:13:53 +0100 Kombi
I have read with great interest the many threads on 3G, suppliers and prices but I still have a few queries unanswered.
I am building a small extension on the north side of the property; this will be a new kitchen/utility. The opening for the window in the new room is quite large at 2400mm wide by 1050mm high. Due to various constraints a sliding window would fit the bill just right. I envisage it to be made of 4 x 600 elements, with the 2 outer fixed and the two center ones sliding towards the edges (do I make myself clear??). I am planning on using 3G and have approached various manufacturers whose name I have found on this forum. But I am wondering if the seals around the moving parts will be airtight enough not ot negate the benefits of 3G?

I am also looking at possibly replacing my existing 2G which is 15 years old. It is a 4-16-4 unit and has BS5713 stamped in between the 2 panes. Does anyone know what were the minimum U value to achieve back then (Bearing in mind that these were replacement units already)? I have one very big window, 2950 long x 1500 high, south facing, which allows the sun to warm the room quite nicely. Would a replacement in 3G, which I understand restrict a little bit the passive heating effect, have much negative influence given the size of the window?
Many thanks in advance for your help.

Nicolas]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2473 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2473 Wed, 03 Sep 2008 16:51:28 +0100 Jax
Thanks:bigsmile:]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3023 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3023 Thu, 27 Nov 2008 13:44:00 +0000 cakewalker
We're faced with changing the roof material (which we may be prepared to do if it's to something visually similar) or fire proofing the shingles. Would anyone have any recommendations for the latter? We have some documentation about John Brash shingles, which have a link to a company they use for fire proofing (Arch Cemicals - their Non-Com Exterior product), but I've drawn a blank trying to establish what environmental issues there may be with fire protected shingles from them. We've been careful in our specification of other elements of the building to use products that should limit the building's environmental impact. The purpose of the building is to study (and foster a respect) of ecology and the environment, and we'd like the building's construction to reinforce that.

Thanks!
Chris]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4545 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4545 Fri, 11 Sep 2009 23:45:26 +0100 captainkirk61 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4517 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4517 Mon, 07 Sep 2009 12:36:43 +0100 timevans2000 A friend did his barn conversion a few years a go and he is still happy it was the correct solution. He has 50mm of foam sprayed to the inner face then he plastered directly on to it. The inner surface maitains the look of the inner walls of the barn as the foam expands to a constant 50mm so you keep all the bumps and lumps. It does look very good and provides an excellent moisture barrer and very low infiltration. Any thoughts?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4505 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4505 Fri, 04 Sep 2009 20:05:51 +0100 mitchino https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4439 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4439 Wed, 19 Aug 2009 17:41:43 +0100 Rosie please help - have rung several local timber suppliers and not got any clearer. Is it ok to buy wood that they say is from an FSC source but they can't show you the certificate because they haven't paid to register (this seems pretty common). Obviously I would much rather have locally grown or reclaimed - any advice on where to find these?

The carpenter doesn't get it and my husband is fed up with not getting on with the job, arrrg! We only need to raise the loft floor to fit more insulation in... unless anybody knows of an extra thin type of insulation? We have been quoted £500 just to make the floor higher so could afford to spend more on insulation if it meant we could avoid the flooring issue.
Still intereted in the timber supply question though, for other jobs.
THANKS!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4421 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4421 Thu, 13 Aug 2009 17:44:25 +0100 Maren
Trying to spec for the most energy efficient windows/doors, but does the U-value not rise when a hole is then punched through the window to insert a trickle vent?

Building control said I need 8,000mm² for trickle ventilation but that I did not have to place this in the windows. Has anybody tried putting trickle vents in the wall? Are the trickle vents even that big a problem for heat loss? What is the best way to do this? And if I have to include trickle vents in the windows is there a best way of doing it?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4153 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4153 Mon, 15 Jun 2009 17:59:19 +0100 Victoria https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4219 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4219 Wed, 01 Jul 2009 10:02:47 +0100 cookie
Its only for the roof and possibly one wall.

If you don't want to say in public (which I've got no objection to) then whisper me please.

Thanks Cookie]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4312 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4312 Thu, 23 Jul 2009 08:51:24 +0100 Jean We have a single story extension (1991) with a pitched roof lined with wood and with the rafters exposed. Can anyone recommend a suitable, thermally efficient, insulation material that can be fitted between the rafters to a depth of 4cms ( to allow the rafters to remain exposed) . Ideally the product used can be just painted without plastering it first!
thanks,
Jean]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4200 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4200 Fri, 26 Jun 2009 15:35:40 +0100 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4214 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4214 Tue, 30 Jun 2009 16:45:04 +0100 valasay http://www.mantlepanel.com/Mantle%20Building%20System/index.html
It sounds good but I'm maybe being sucked in to the marketing message.
I'm considering Sips and Durisol for our new build at the moment and don't quite know if this is just Sips by another name or is it a third option?
Thanks in advance for your help.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4210 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4210 Mon, 29 Jun 2009 21:14:41 +0100 storm https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4232 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4232 Sat, 04 Jul 2009 11:00:32 +0100 cookie
Need something that will fit with brick slips ideally, fixing to the building without bridging insulation is going to be an issue, any suggestions before I plough endless hours searching the internet?

Cheers Cookie]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2847 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2847 Sun, 02 Nov 2008 09:25:52 +0000 Mike George
Would anyone recommend this application in light of the BBA and the below Q and A ?

[Reproducd in full from http://www.foam-insulation.co.uk/spray-foam-roof-tales.htm]

1) It causes the roof timbers to rot when timber is encapsulated in foam.

Answer: Firstly, foam in itself does not rot timber or affect it but damp and water does. The cell structure of ‘roof grade’ polyurethane foam is 95% closed cell and 5% open cell. The closed cells afford the foam its water resistance properties whilst the open cells provide a means for the foam to ‘breathe’. In essence circa 5% open cell foam allows the substrate (tile, slate, timber etc) to ‘breathe’ and act as a semi permeable membrane. The cellular structure of the foam will act to dry out excess damp and work like slow blotting paper whilst the foam remains water resistant.

If the correct type of foam is used rotting of roof timbers cannot occur as damp will be evaporated off via the open cells whilst affording resistance to water penetration and condensation. If foam is used against timbers it must not be marine grade foam that is designed to be effectively 100% closed cell structure but rather a foam that has circa 5% open cell structure.

2) Slates or tiles once bonded with foam cannot be removed and it is almost impossible to repair a broken tile or slate once spray foam sealed and bonded.

Answer: Spray bonded tiles and slates can be removed with a few tricks of the trade. A quick and easy way to remove foam bonded tile or slate is to use a old saw and from the outside roof saw the foam bond away by pushing the saw up between the tiles or slates and gently sawing. Foam can also be removed by mechanical abrasion, a carpenter's wide chisel works well on foam as the material is easy to shape and cut. If a tile or slate has cracked then the back of a brick layers hammer can be used to gently chip away the tile so as to insert a replacement tile or slate.

3) Spray foam seal will stop a roof leaking without making any roof repairs first.

Answer: Spray foam is water resistant rather than water proof and will generally stop water from penetrating. However, if the foam has prolonged exposure to water the open cells will act to transmit the water and drip from one side to the other. This is a relatively slow process particularly if low percentage open cell foam is used. In general use, foam will prevent the ingress of wind blown rain but it is not itself designed to be a final roof covering material. It is quite satisfactory to use as a quick touching material but broken and badly chipped tiles or slates must be replaced first. Also, it is not always possible to ensure that the foam has got to every area underside of a roof; a cracked tile will still potentially let in water despite foam being installed. Don't rely on foam alone to make an already leaky roof leak proof, do the repairs first, replace any cracked or damaged (e.g. shaled, frost bitten, chipped) slates or tiles and also repair any leaking flashings and valleys. Then foam bond to stabilise and insulate.

4) Spray foam is very expensive.

Answer: Spray foam is a superior product with superior benefits and comes into its own when the following are required in one hit: roof stabilisation, low loading, excellent thermal and sound insulation, curing nail fatigue, fast time to install, minimal disruptions to other works and very easy retro fit creating a warm roof. Because spray foam creates a composite and sealed product (the foam and the substrate) there is no requirement for top ventilation on the ‘cold’ side so another cost can be saved that of top venting the insulation so as to avoid condensation.
There is no method and no product that can compete to achieve this as cost effectively as spray foam. Spray foam is remarkable cost effective for the applications it solves best and will save many consumers money over say the cost a new roof or a reroof, perhaps up to 70%. As always, cost has to be judged against investment value for money and spray foam should be judged as such like everything else competing for your wallet's attention.

Iso-Spray foam can also be provided in low cost professional kits so contractors do not necessarily have to be employed. Do it yourself and save money.

5) Spray foam is toxic and releases toxic gases over time (‘off gases’).

Answer: This is true of formaldehyde based foams but not true of polyurethane foams which are inert and can actually be eaten without toxic effect but not recommended! But did you know that the binding agent used in mineral glass/wool insulation uses a formaldehyde base? Iso-Spray only use polyurethane foams.

6) Spray foam attracts vermin that will eat it.

Answer: Spray foam polyurethane is not only inert it also has zero calorific value so vermin do not attack it for its food value. Spray foam when cured is relatively dense (though light weight) and hard so will help prevent vermin from gaining easy access.

7) Spray foam is too heavy and will put excess loading on the roof timbers causing them to buckle.

Answer: Where this one came from we do not know but it is rubbish. Ever held a piece of polyurethane foam? It is as light weight as can be, even the ‘high density’ foams.

8) Spray foam is very flammable and pose a major fire hazard.

Answer: Roof grade polyurethane foam meets British Standard Class 1 fire rating and is therefore resistant to burning and ignition. Roofing felt poses a greater fire risk. But true, the stuff you buy at the local DIY store will be very flammable, do not use on a roof as a cheap substitute, not only is it a fire hazard but its largely open cell structure makes it useless as a water sealer.

British Standard Class 0 can also be achieved with a spray foam system by a two coat process.

Do not be tempted to use a contractor unless he is willing to specifically show you a fire test on a sample of spray foam before installation. It is not unknown for a rogue cowboy contractor to tell you that they are using Class 1 foam and then install something completely different because it is cheaper to supply and makes the contractor even more profit. A none Class 1 foam is just a fire bomb waiting to go ignite, would you want that for your family?! Not to mention that insurance companies are unlikely to insure the property if they knew and the difficulty in selling the property later on. Class 1 is also the legal minimum that can be accepted on all commercial and public buildings.

9) The Building Regulations rule out the use of polyurethane spray foam

Answer: No one has yet been able to cite which particular Regulation rules out the use of spray foam because no such Regulation exists! This objection is often used by arm chair critics who like to sound more knowledgeable that they actually are. The Building Regulations are in essence the minimum legal construction standards in the UK, they do not define what products can and can’t be used only what standard a product or design must meet as a minimum.

10) Building Regulations on Ventilation Rule out the use Spray Foam on roofs.

Answer: Another myth usually propagated by armchair know-it-alls on various websites. There are indeed Building Regulations for roof ventilation. The 2006 Building Regulations in Part F Ventilation essentially require that the building must have adequate ventilation and provision to prevent condensation occurring in the roof structure. Use of spray foam helps that requirement because it provides a ‘warm roof’ which by definition decreases the likelihood condensation.

Ventilation is required in areas where relatively warm and moist air can meet cold surfaces and the potential for condensation will exist. Spray foam acts to minimise condensation by providing a ‘warm’ surface that resists condensation so they requirement for ventilation is reduced. Also, spray foam does not have to be ‘top vented’ by a continuous air gap, as is the case with mineral wool and friction fit insulation products, as it forms a composite product where there is simply no air gap for condensation to occur in.

The Building Regulations on Ventilation actually make spray foam in many situations the only viable way of complying particularly in retro fit conversion projects like loft conversion and barn conversions where head room needs to be maintained and not sacrificed for bulky non polyurethane foam insulation.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4127 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4127 Tue, 09 Jun 2009 11:01:25 +0100 jamesingram
anybody heard about this ?

"Novacem's cement, based on magnesium silicates, not only requires much less heating, it also absorbs large amounts of CO2 as it hardens, making it carbon negative."

"According to Novacem, its product can absorb, over its lifecycle, around 0.6 tonnes of CO2 per tonne of cement. This compares to carbon emissions of about 0.4 tonnes per of standard cement. "From that point of view, it's attractive," said Rachael Nutter, head of business incubators at the Carbon Trust."

"A spokesperson for the British Cement Association expressed a sceptical note, saying that though there was much ongoing laboratory work on new types of cement, there were also problems. "The reality is that the geological availability, and global distribution, of suitable natural resources, coupled with the extensive validation needed to confirm fitness-for-purpose, make it highly unlikely that these cements will a be realistic alternative for volume building."

Vlasopoulos responded that magnesium silicates are abundant worldwide, with 10,000 billion tonnes available, according to some estimates. "In addition, the production process of our cement is of a chemical nature, which means it can also utilise various industrial byproducts containing magnesium in its composition." He is confident the material will be strong enough for use in buildings but acknowledged that getting licenses to use it will take several years of testing"

sounds interesting , but I guess one expected answer here would be we should just use lime

cheers Jim]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4201 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4201 Sat, 27 Jun 2009 18:18:59 +0100 john_connett
Is low humidity a problem with MVHR in the UK? Or is this option targeted at places with cold, dry, alpine winters?

I'm wondering what features a MVHR should have for my house renovation in Cambridge.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3676 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3676 Sun, 01 Mar 2009 19:14:32 +0000 richy https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4166 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4166 Wed, 17 Jun 2009 17:13:38 +0100 TomN
http://www.theengineer.co.uk/Articles/306208/VPhase+energy+saver.htm

It seems like quite a bold claim, and they usually turn out to be red herrings but is there any truth in it?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4094 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4094 Tue, 02 Jun 2009 18:53:50 +0100 James Norton
Environomix

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3916 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3916 Thu, 23 Apr 2009 10:49:18 +0100 IDN101
Can anyone recommend a source (ie company) of riven slate for flooring, preferable close to Shropshire?

Many thanks
Ian]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4092 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4092 Tue, 02 Jun 2009 17:05:44 +0100 Mike George
What do we think?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3723 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3723 Mon, 09 Mar 2009 10:47:38 +0000 brunos
Many thanks
brunos]]>