I'm impressed so far, it was 10 degree outside last night and the internal temperature remained at 19 degrees with no heating at all. Apart from the dogs farting.
We've just done this too, hope it'll be nice and cozy this winter ! :)
Oh that takes me back, James, I did that number on a house I was in back in the late 70s - worked a treat.
I have a question but, perhaps, I ought to be posing it in the ‘Construction’ group - and perhaps I will do that as well.
SPRAY FOAM: does anybody have any experience of it over here? (Do watch this video, if only for the entertaining way it erupts from its cavities like an alien beast).
Amongst my assorted cow sheds and odd ‘dépendances’ I have a hay loft I’ve converted into my guitar repair workshop and bloke den. Too hot in Summer, especially since I replaced some of the slates with clear polycarbonate, and now the weather has suddenly changed, it’s too cold. As it’s a creaky old agricultural bodge-up of a structure, surmounted with those asbestos-cement-compound slates and currently leaking a gale in every corner, I think spray foam is the answer; it will plug all the holes, insulate well, add strength to the structure and glue everything together. The roof does not let any rain in at present, even in a howling storm and I have no intention of replacing it in my lifetime - so - does anybody know where I can get reliable kits of this stuff from over here in France because, for certain, you won’t be able to ship it from the States without a lot of hassle? I’ve googled all over the place but no luck so far.
And what do you think: good idea or…?
I don't agree James, There is hardly a place where reflective film shouldn't be used, it makes a great way to seal the roof area from air movement which is the biggest loss of heating in any building. Virtually all ovens and heating appliances contain a reflective foil to radiate the heat back in. However that is usually backed up by a bulk insulator and that is the best method, the combination of the two (installed properly) is greater than the sum of the parts.
Notice I have not specifically said multifoil as these are often advertised badly as a reflective film with say two rows of bubble wrap inside is NOT and never will be as effective as 200mm of glass fibre/rockwool. It maybe more effective at reflecting heat than 200mm of wool style but even the thinnest reflective in addition to say wool style would produce far better results. There are now companies in the UK setup not just to test new builds for building air leaks but older building stock as closing off the air leaks saves more money and provides better living space than many other added insulation products.
I would like to know how far a kg of cellulose fibre would go at say 100mm thickness? Actually doing part of my roof very soon (long story) but that is why I tested degradation of multifoils for so many years before taking the plunge. Because of the roof construction I will be fitting a 30mm multifoil (bankrupt stock clearance) and doublage 80mm black polystyrene+10mm plasterboard which should give a U 0.18, if the polystyrene was foiled to like Reticel, Kingspan etc that would be U 0.15.
It would take 400mm if a fibre/mineral wool to achieve the same level and that is by the hot box test data but the film can reflect out the worst of the heat in summer.
In my opinion the multi-foil products should only be used when there is no other option, ie space is very tight.
Thanks John, I've just looked at Brico Depot to see how they compare on price. They are often very competitive but not on this occasion.
The cellulose fibres from Kiloutou where I got mine came to exactly 1 euro per kg inc. VAT and the hire of the machine was 122 euros per day although they were happy to let me have it for the weekend for the same price.
I used 700 kg so the cost was 822 euros inc VAT
The Brico Depot price today for the fibres is 1.26 per kg inc. VAT. If they provide the machine for free it's still more expensive at €882 for the same job.
Brico depot are hiring out the blower FOC if you buy a certain amount of blown fibre. Yes it does compress over time and need a top up as do most mineral wool types. It also blows around a bit with drafts so it's usual to spray with water/dilute wallpaper paste to make a crust on top to lessen this effect.
I went to a demo chat by a well known insulation manufacturer who had a loft as a demo piece showing how little it took to pass warm air through it. Obviously if it goes down thick enough this effect is lessened.
Multifoils work as reflective barriers with some insulation properties, primarily they make a sealed box out of the area being insulated preventing drafts and therefore heat loss. The shiny surface definitely reflects out the majority of the heat in summer or keeps it in if applied to the inside face. They must have air gaps as this helps with dead areas of air acting as insulation and on the other side the escape of moisture to the air.
Having heard the "Pros" put down about how they degrade, I got samples of 5 different manufacturers products fastened them to a board and left that outside in all weathers for the last 6 years on my shed roof, absolutely no degradation of any of the products occurred so all I can say is the "Pros" talk BS to leverage other types of product. On it's own multifoil is not good unless it's for reflection of heat rather than retention of heat so must be backed up by a bulk insulation. Together this can mean a much thinner overall insulation package (210mm - 230mm) to achieve good/great levels of insulation with typical U values of 0.20-0.18 but it must be used properly and taped and sealed or it will end up pointless.
Trust you to be in on the act. Does James get any of the proceeds from autograph signing?
I'm his agent, autographs cost... ;-)
Thanks James for your reply. I would say from the pictures that that's a job well done. Loved the video. Are you an actor in your spare time?
The stuff is treated with borax for flammability and that is a deterrent to rodents. Good news as they would wreck it's efficiency.
Thanks Veronique for your prompt reply. Much appreciated.
I don't know if it is a deterrent BUT until the insulation went in, virtually every night some creature - possibly a mouse, more likely a lérot or a loir - had a fine time, for what seemed like hours on end, messing about with nuts up there (amazing how much noise a rolled nut can make) and since the insulation went in I have heard nothing.
Hi James. Would this insulation be a deterrent to mice? Thank you.
Elaine, if it is not floored then perhaps one of the Fermacell range of sheets, in this case for floor covering, would solve that.
Ian, multifoils, we have been advised by more than one insulation installer, have a short life compared to other materials until you reach top of range which then cost more than more practical materials. I started out wanting to use it for our insulation work but have been convincingly dissuaded.
Thank you for this link Ian. I had sen similar ones previously. The main area of dispute hinges on the method used for testing. The traditional “hot box” method used for conventional insulation does not produce good results w its multi foil but it is claimed that testing under “real” conditions, as several of the comments point out, produces quite different results. I note that multi foils now have Agement certificates in UK. Anyway it’s done for better or worse so time will tell. We certainly don’t have the problem with mice living in it as they did in the old LdeV which I removed from much of the house over the past couple of years.
If multifoil is the same as "isolant mince aluminium-polystyrène" then this page can help :
http://conseils-thermiques.org/contenu/isolant_mince.php
Essentially, multifoil is an accessory to insulation, not an insulant in itself, apprently. We used it for the eaves part of the roof where it came down over the top floor bedrooms and was not accessible from the loft. It was admissible for the subvention but only up to a certain quantity. Professionals don't seem to favour it too much.
Great video James, our attic is very low and awkward, and not floored - this could be a good re-insulation solution for us. Aside from fibreglass, I would be worried about insulation (for example, what you used - dry blown cellulose) being "eaten" or attacked (robbed for nesting/building), or used as nesting areas, as our roof is not sealed from the outside.
What are your thoughts? And also, what kind of place sells it and rents out the equipment? I've not seen it on my travels. Thanks!
A very interesting video and post. I wonder if you will find the loose fill blows around a bit if you have a storm as your roof seems to have nothing except the tiles between the loft and the weather. You may need to line the roof with something - maybe even builder's polythene would do to keep the wind out. Although clean and quite cheap you do lose the option of using the loft for storage.
I used a mutifoil (Superquilt) under the rafters on our roofs and then counter-battened before we fitted the plasterboard, where the rooms extended to the roof, to give the required 25mm air gap each side of the multifoil. I will do the same in the loft but use a cheap fibre board underneath instead of plasterboard. The multifoil cost just under £9 per sq M delivered to UK (I had a load of stuff coming out here at the time so it cam here for nothing. I also used it inside many of the stone walls especially for the bathrooms to keep them warmer and the wine store to keep it cooler in the summer.
We had the roof renewed (not the timbers) when we bought the house and opted for Valtech multifoil with a breathable membrane under the tiles. It was very expensive (€38 per sq M) and I am not sure if it was the right choice although I researched it quite carefully at the time.
I know there is some controversy over the effectiveness of multifoils but it certainly keeps the rooms cooler in the summer. We are not here for much of the winter so I don't know how ell it would perform in cold weather. There seems to be a view that it works better in reducing transmission of radiant heat in some quarters.
Has anyone else used multifoil?