Green Building Forum - Insulation Tue, 14 Jul 2026 16:55:03 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249098#Comment_249098 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249098#Comment_249098 Sun, 30 Oct 2016 21:33:39 +0000 Michael1 Is there a chart or something similar to use for checking Insulation, where it's for and such like? I want to insulate the exterior the floors and the loft space in my house and don't know what is best where if that makes sense.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249105#Comment_249105 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249105#Comment_249105 Mon, 31 Oct 2016 09:06:13 +0000 Peter_in_Hungary Insulation varies with construction of the building but for a standard sort of house however IMO

Exterior - EPS EWI with EPS bead cavity fill if relevant (i.e. if you have unfilled cavities)

Loft space - Glass wool, as thick as you want up to 400mm

Floor - depends upon your floor construction. Solid floor - high density EPS with new floor over but this raises floor level (but cheap and quick), dig out old solid floor and replace as above (expensive and messy), for wooded floors fill between joists (glass wool, vcl supporting net etc. read all about it on various threads here) or remove wooden floor and replace with insulated solid floor. Other options available but floors are probably the most difficult to insulate unless you can go for the first option above.

With any insulation works attention to detail is v. important and if you are getting trades people to do it then you will need to watch then like a hawk to ensure detail is attended too.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249106#Comment_249106 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249106#Comment_249106 Mon, 31 Oct 2016 09:12:15 +0000 ringi
But if you have UFH, you need VERY good floor insulation, otherwise you put most of your heat into the ground.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249107#Comment_249107 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249107#Comment_249107 Mon, 31 Oct 2016 09:23:18 +0000 SteamyTea Is it information on application. If so, then it is really down to the manufactures specifications.
There are some fundamentals that are common, i.e. 'wools' insulate, but allow air to pass though them relatively easy, sheet insulation can insulate just as well, but hinder the passage of air.
The problems start when the condensation is taken into account, 'wool' types can hold onto water for longer than sheets types, though this is not always true.
Different insulations are also affected differently by moisture, some rot, some don't.

Sound transmission is another area that is affected by insulation, blown cellulose is one of the best in practice.

Then, to cap it all is the vapour control layer and wind/weather tightness layer.
Some insulation types need a physical break between components i.e. roof insulation, others don't i.e. loft insulation.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249108#Comment_249108 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249108#Comment_249108 Mon, 31 Oct 2016 09:40:54 +0000 DarylP It is quite concise....
Good luck :smile:]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249110#Comment_249110 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249110#Comment_249110 Mon, 31 Oct 2016 09:55:00 +0000 RedDoor http://www.superhomes.org.uk/resources/whats-best-insulation-material/]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249117#Comment_249117 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249117#Comment_249117 Mon, 31 Oct 2016 12:24:32 +0000 ringi Posted By: SteamyTeaThere are some fundamentals that are common, i.e. 'wools' insulate, but allow air to pass though them relatively easy, sheet insulation can insulate just as well,

Sheet insulation is often installed with gaps, so making it close to worthless, 'wools' insulate is easy to push in without having to cut it 100% to the correct size, so tends to get installed better.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249265#Comment_249265 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249265#Comment_249265 Wed, 02 Nov 2016 07:18:26 +0000 cjard Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249266#Comment_249266 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249266#Comment_249266 Wed, 02 Nov 2016 07:18:57 +0000 cjard Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249274#Comment_249274 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249274#Comment_249274 Wed, 02 Nov 2016 10:07:25 +0000 fostertom Posted By: ringiSheet insulation is often installed with gaps, so making it close to worthless, 'wools' insulate is easy to push in without having to cut it 100% to the correct size, so tends to get installed better.'Neither of the above', in my book. True about sheet insulation - but do you really experience that about wools getting installed better?

The prime advice with wools is to not 'stuff' but to cut accurately to fit so it lies flat, uncompressed. I agree with that but it's impossible to cut/fit well enough around obstructions, even if just about feasible between truly parallel timbers at equal spacing. For that reason I see wools as the lowest of the low, gaps everywhere in practice.

Sheet insulation - on the face of it even more difficult to cut/fit well. Therefore be prepared to foam most or all of the joints! Even a fag-paper width 'tight' joint is a convection channel - tiny maybe, but multiplied all over the insulation surface, adds up. A wider joint gap is a serious loser. At least, start early with a design strategy that minimises opportunity for gaps - e.g. as Andy describes in http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14664&page=1.

What gets over the gaps problem is either blown-in or foamed-in-place insulations.

Blown-in cellulose fibre (Warmcel) or glass wool has to be in a closed volume e.g. studwork, or underlined raftering, not lying loose e.g. between/over ceiling joists. It swirls around to find and fill every tiny space, and remains under slight compression forever. Thus convection air gaps are eliminated.

And as a bonus the whole body of it (cellulose fibre anyway - not sure about glass wool) is fairly airtight, so when coupled with OSB as one of the facings, the overall sandwich is reliably and long-term robustly airtight, not a fragile tricky long-term unknown membrane or tape in sight. Also well 'breatheable', and hygroscopic too! To me, the OSB plus Warmcel combo is The Answer - solving the insulation-gap problem, the airtight membrane need, 'breathability' and hygroscopicity, all in one economical, foolproof high performance package.

Foamed-in-place can only mean Icynene, for multiple reasons, def not traditional poluyrethane foam. Tho so different from blown-in Warmcel, it shares many of its characteristics. Tho it doesn't need that closed space, it teams up with OSB for all the above good reasons, except the benefit of hygroscopicity.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249431#Comment_249431 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249431#Comment_249431 Fri, 04 Nov 2016 07:20:17 +0000 Michael1 Sorry for not replying earlier, packing ready for the move. Cost although is always an issue I am more than willing to spend it to save it. The blown in for the loft sounds good and as I will be putting rooms up there at some point does the blown in eliminate the need to insulate hot and cold water pipes if they are in the blown in?
Is the blown in suitable for exterior walls, these are stone rendered, I want to clad in timber so would need to frame therefore blow in from the top maybe?
The floors are all tiled or stone and I don't mind losing an inch or two off the height.
Regards
Michael.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249486#Comment_249486 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249486#Comment_249486 Sat, 05 Nov 2016 00:04:46 +0000 djh Posted By: Michael1does the blown in eliminate the need to insulate hot and cold water pipes if they are in the blown in?
Should do as long as there's an inch or two of coverage over the pipes.

Is the blown in suitable for exterior walls, these are stone rendered, I want to clad in timber so would need to frame therefore blow in from the top maybe?

It should be. In the case of cellulose, they usually inject from the side rather than from the edges so the material spreads to fill the entire volume. I would expect it's the same for EPS beads or anything else but I don't know.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249495#Comment_249495 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249495#Comment_249495 Sat, 05 Nov 2016 05:27:57 +0000 Michael1 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249498#Comment_249498 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249498#Comment_249498 Sat, 05 Nov 2016 07:23:11 +0000 tony Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249502#Comment_249502 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249502#Comment_249502 Sat, 05 Nov 2016 08:55:44 +0000 Peter_in_Hungary Posted By: Michael1My thoughts are 100mm battens screwed to the wall then covered with a fine net of some sort to hold the insulation and cover with tongue and grooved boards,
IMO for the external walls you would be better off with EWI (external wall insulation) It is better for the fabric of the house as the whole structure is kept warm.
For the loft - when will you do the rooms in the loft? if it is some years away it may be better to put normal glass wool (about 300mm thick would be good) and properly insulate the rooms in the loft when they are built.
EWI can be done DIY or part DIY (get tradespeople to put the final top coat render or the outer adhesive and top coat render depending on your skill, ambition, available time, cash etc. Glass wool is easy to DIY and I would guarantee you would do a better job (attention to detail in places you can't see) than tradespeople working to a quote.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249508#Comment_249508 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249508#Comment_249508 Sat, 05 Nov 2016 09:37:49 +0000 Michael1 The rooms upstairs will be done within two years but am happy to do the insulation in the loft to a high standard whilst waiting just in case it gets put back. I am more than willing to raise the height of the joists to put thicker insulation in. As for EWI I do want to timber clad so will again go for the best I can get but on a DIY level, is there any reason for not doing 100mm battens and blown in or is there something better.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249516#Comment_249516 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249516#Comment_249516 Sat, 05 Nov 2016 11:18:56 +0000 Peter_in_Hungary
I put EWI on my building with very good results. You can choose your thickness (the link mentioned on the other thread - http://www.vesma.com/tutorial/uvalue01/uvalue01.htm - will instantly give you the results of increasing the insulation thickness) The additional cost of extra thickness is just the additional EPS + a bit for the mechanical fixings, adhesive and render and work remain the same. I put 100m of EWI on and this improved the walls from U of 1.6 to 0.3. If I had put 200mm on then this would have given a U value of 0.17. (100mm because thicker would mean altering the gutters and eaves and it is rented accommodation) It would be better for the building to EWI.

If you put the insulation on the inside then there are always problems with condensation behind the insulation, the need for good VCLs and cold walls don't help buildings. Read threads here about IWI. A couple of people with stone buildings have built a timber frame with insulation inside the stone structure and ventilated the gap between the timber frame and stone, (a house inside the barn ) EWI avoids all these issues. You can still put up your timber cladding but this would go up on tile battens. What ever you do on the inside you will need to put a parge coat on the walls to stop the gale.

Another point of EWI vs IWI. If you are living in the house permanently then IMO EWI gives a much more stable temperature (and cooler in the summer) but takes longer to heat up. IWI heats up quicker but the temperatures fluctuate. EWIed walls will retain the heat over night whereas with IWI there are only the internal walls to stabilise the temperature. In my book it is EWI for permanent living and IWI for weekend houses.

You don't need to raise the hight of the joists to put in thicker insulation unless you want to use the loft for storage and alike, just fill to the top of joists and then lay insulation on top. It would probably be worth putting heavy paper on top of the loft insulation as I suspect you have a well ventilated loft (= a gale blowing through unless you have roofing felt) and the paper will stop heat loss through wind wash.)]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249520#Comment_249520 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249520#Comment_249520 Sat, 05 Nov 2016 15:05:20 +0000 gyrogear
https://www.youtube.com/watch?v=Q2cmhK8uex4

Maybe give him a ring and ask what the R value is !

gg]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249526#Comment_249526 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249526#Comment_249526 Sat, 05 Nov 2016 16:45:22 +0000 Michael1 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249535#Comment_249535 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249535#Comment_249535 Sat, 05 Nov 2016 19:08:59 +0000 Peter_in_Hungary The almost universal EWI is EPS (expanded polystyrene) sheets that are 1m x 500mm and to a thickness of your choice, glued to the wall (with mechanical fixings as well) covered with a layer of adhesive (for mechanical strength) and a thin film acrylic render for weather proofing and to make it pretty. Its the easiest system to use and is suitable for solid stone walls. IMO there would be no point in battening out the wall and using blown insulation which would then need some sort of render or sheeting to make it weather proof.

The loft space insulation has nothing to do with the EWI (other than they should be thermally connected).

Roof insulation can be blown insulation between the rafters but needs to be self supporting or blown in to any depth between and over the joists. But this is not a DIY job. If you are thinking to have blown insulation between the rafters then you will need a good breathable roof membrane under the tiles first. If you do the insulation on the floor of the loft then the breather membrane can wait until you build the roof in (if you haven't already got one.

If you want to DIY the roof insulation then IMO it is glass wool or equivalent between and over the joists. If you use roll out insulation then it will be fairly easy to remove and reuse when you build in the roof. If you use pour in or blown in then this will be a pain to remove and reuse come the loft build.

When I built in the loft of one of the rental houses I used glass wool on the sloping part of the ceiling by battening out the rafters to the required depth then put in the glass wool which was held in place with bailer twine stapled to the battens until the plasterboard went up. The dwarf walls at the side were also insulated with glass wool (as was the remanent of the loft). All DIY]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249543#Comment_249543 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249543#Comment_249543 Sun, 06 Nov 2016 05:02:41 +0000 Michael1 At the moment there isn't any insulation in the house, so that's my reason for raising the joists. I intend to run the services in the insulation ready for the conversion. Also I want to insulate the concrete/tiled floors in the downstairs so was thinking 50mm sheets of insulation with a wooden floor laid directly on top, should I batten the floor first or could I lay the flooring directly on the insulation?]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249573#Comment_249573 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249573#Comment_249573 Sun, 06 Nov 2016 23:02:05 +0000 Gotanewlife Posted By: Michael150mm sheets of insulation with a wooden floor laid directly on top, should I batten the floor first or could I lay the flooring directly on the insulation?There are at least 3 current threads covering this issue. In essence views vary from one member (IIRC P-i-H above) who has put down high compression XPS with wooden flooring directly over with no problems to others who would want you to fit battens and then DIY laminate 2x9mm ply over the top! (but they don't appear to have worked with heavy duty XPS before). Given you have a solid floor under and given you use 300MPa XPS then if you use uni-click laminate or glue T&G over a foam underlay you don't need anything else.....IMO of course.]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249574#Comment_249574 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249574#Comment_249574 Mon, 07 Nov 2016 00:48:48 +0000 gyrogear Posted By: Michael1should I batten the floor first or could I lay the flooring directly on the insulation?

I battened to 60mm XPS then nailed salvaged planks to the battens, to give a "17th Century effect". If I were doing it again, I probably would not batten and would simply use a thickish "pad" of double-backed carpet adhesive at each plank-end.

In the garage I laid 9mm T&G OSB directly onto 30mm XPS, it makes quite a difference; I left 1 cm around the walls and used XPS shims every so often, to hold it all. After I learned that the T&G should not be fully butted up, but that is a tough one to apply !

(garage walls are lined with 40mm XPS, with lime/muck render over).

gg]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249575#Comment_249575 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249575#Comment_249575 Mon, 07 Nov 2016 07:40:21 +0000 Michael1 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249576#Comment_249576 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249576#Comment_249576 Mon, 07 Nov 2016 08:48:19 +0000 DarylP ]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249584#Comment_249584 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249584#Comment_249584 Mon, 07 Nov 2016 11:35:36 +0000 Michael1 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249588#Comment_249588 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249588#Comment_249588 Mon, 07 Nov 2016 12:48:01 +0000 bxman
but I found them very instructive
lessons that apply to all forms of insulation to my mind


https://www.youtube.com/watch?v=NpkXxHRp8U0

https://www.youtube.com/watch?v=WXr5E3gb0P0]]> Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249593#Comment_249593 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249593#Comment_249593 Mon, 07 Nov 2016 15:36:56 +0000 Michael1 Insulation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249596#Comment_249596 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14663&Focus=249596#Comment_249596 Mon, 07 Nov 2016 16:30:56 +0000 Gotanewlife