I was just at an energy-saving home show and came across a product I am thinking of using... Somehow my garage (once a carport) was lined in plywood (not sure if it was legal at time of construction) - the walls have been lined with drywall, well and good, but the ceiling still is plywood. I had to cut some access holes into the ceiling to rectify some plumbing issues and plan to leave some manholes in there so I will have future access. It transpires that there was no moisture/air barrier put in, and the insulation has mostly dropped out of the ceiling joists and rests on the top of the ceiling material This product I am interested in is a foam-core material with a foil backing, and a white finished side which is paintable. It would be easy to fix it in such a way that I could remove it in the future or just build said manholes. I had already figured I would have to take the whole ceiling down and probably get spray-on foam insulation done, as I believe the spray stuff works as an air/moisture barrier. The master bedroom is above the garage and needless the say the floor is cold in winter, and I would like to remove the carpet for a wood floor. In its present state that would make it a lot worse....on the upside, nothing in the garage freezes in winter! (door is an insulated double skin type) So, does anybody have any thoughts or concerns or experience with the stuff? I was thinking of using the 1' material which is claimed to have an R27 rating, impressive for the thickness. If I go with spray on, I am going to have an awkward situation ensuring the plumbing found up there remains on the warm side of the envelope, I am going to have to build a complex box around it, probably with styrofoam insulation as there is only an inch or so clearance to the false ceiling below. If I use this stuff, I can go right over the existing ceiling. I can leave the old insulation in there (although I suppose the existing insulation would be more effective if it was back up between the joists, but I don't really have an option to get it back up there) Insulating it on the surface would be great in that the whole space would end up on the warm side of the house, being better and simpler for the plumbing. My concerns? Fire, and mechanical damage, it is coated/covered but will be easy to damage. I suppose I could drywall over it if I used long screws...not sure how effective that would be but would be an option. Big attraction is leaving everything else alone. Cost is around CDN$ 1.41 psf or around $45 per 4x8 sheet which should be at least federal sales tax-free, as an energy-saving product. According to the literature it's a class-a product according to the fire rating test, I don't understand the rating system too well but understand it's better than some material, not as good as drywall itself, but would appear to satisfy the legal requirements for the most part (I will see what I can dredge up on my local codes) Any thoughts? URL for company is below: Here is a link that might be useful: P2000 Insulation systems

Depending on the thickness you are talking about, you can either fir out the studs or use multiple layers of drywall. eg if the finished thickness needs to be 1 inch, you can use 1 layer of 3/8 and 1 layer of 5/8 and you get an inch. If it is much thicker than that, you would probably want to fir out with wood and then use 1 layer of drywall. You can cut wood to any width you want, so the options are endless. Either way, you will probably need to skim coat over the top to make it 100% smooth. Any hand made wall isn't going to be the exact same thickness at each point, but a decent drywall/plaster guy will be able to blend them to make them so that nobody will know the difference. Re Insulation - You may or may not be able to blow in insulation from the top. Before the invention of plywood sheathing, it was common to have diagonal bracing within the walls. To fill the wall cavity, you would likely have to drill additional holes to insulate below the cross bracing.

I don't think you need to worry about explaining anything. I'd just tell them they get their final payment when the ceiling's finished, whenever that is. Years ago I had my floors refinished, and part of the job was to put a threshhold between the hall and living room floors (two different woods). Because the house is old and wonky, it wasn't a simple task and they couldn't complete the job that day. It was scheduled for another date and still they couldn't fix it when they came out. I called several times to reschedule, and several months later someone came out and the same thing happened and the dope couldn't create the threshhold! I let it go, figuring they'd call and have it fixed when they wanted their money. Sure enough, they called at the end of the year saying they were trying to close their books. I said fine, but they'd have to complete the job before I made the final payment. I reviewed how many times they had been out and didn't do it. They never called back. I paid a carpenter to do it and pocketed the final $200 I owed the floor people. This was an unusual experience for me. Most of my contractors get their work done in a timely manner and get paid promptly. But it's always good to be careful, especially when using someone new. Tina

Thanks for both your thoughts, I thought the cup was a little tryhard, I hadn't watched the video itself. I must say I wondered what made the foam so special, reading between the lines I thought they might have been inflating the R-value somehow by perhaps arguing that it's more effective because of the moisture or air barrier quality or the foil (a lot of homes in Australia use only foil insulation) or something... I did little googling apropos of the fire rating all we have is the testing body's word for it and I'd have to check them out too so I guess my spidey senses were tingling, I was thrilled at the intial prospect of just sheathing the existing ceiling, fire rating aside my other concern was damage, being a garage and all, it'd be easy to dent and tear. Annz, I hadn't thought of blown-in insulation but I do have to consider a moisture/air barrier too, there was none put in, it should have been under the flooring I suppose although I have seen the plastic put on the underside of the joists in order to help retain the fibreglass insulation (am I right about that, is it code in most places?) - I would be back to the idea of removing the ceiling, but, either way, even if the method was legal back then (not having air/moisture barrier) it seems foolish - the current drywall lining on the walls has plastic, but unless the garage is heated, it's still the cold side - unless it's relative, certainly outside'll be colder.... So blow-in insulation could work assuming adequate access and would make life easier, It'd be blown in above the fibreglass which has dropped out of the joists, but my point regarding the box around the pipes is this - there's a dropped section of the ceiling, a plenum or whatever you want to call it, where the drains etc for the upstairs bathroom etc run, (you can actually look right up there to the back of the shower head) and I've currently got a small leak somewhere around one of the drains (did no damage fortunately and a bucket catches it, I have been putting off the repair) - anyway the pipes sit low, almost flush to the underside of the garage ceiling....drains/pipes should be on the 'warm' side of the building envelope, in this instance there is only an inch or so of clearance underneath so little room to insulate under (to prevent the pipes freezing) so I'd considered styrofoam under it, and up the sides to the underside of the upper floor to include it in the 'warm' side of the envelope, so the rest of the area's insulation isn't affected by this one potential cold spot... All the styrofoam stuff I'd seen is like R-12 or less so I wondered about this stuff and its claims. I'll read a little further.