Insultating the floor of an out building
Situation: I have built a 10×10 shed (in the Seattle area) that I am finishing to be used as an office. The shed sits on concrete blocks on presure treated timbers. The cleareance is not enough to crawl under (without digging out dirt) to put insulation under the floor.
I want to insulate the floor and have a couple of ideas.
I have been looking into putting a floating floor over rigid insulation (Rigid Board polyurethane or isocyanurate).
http://www.eere.energy.gov/consumerinfo/factsheets/eb7.html (section: Insulating Slab-On-Grade Foundations) talks about the layers it recommends. I have done this once before when insulating an RV (and didn’t follow all the layers mentioned in the above link and it is holding up after 10 years). I placed the rigid insulation over painted metal, then put flooring over it. I don’t see any issues with the rigid insulation crushing. The rigid insulation is foil faced on both sides for a vapor barrier.
Has anyone applied a floating floor on top of rigid insulation either directly or under another layer of subfloor?
Would it be better to dig out two trenches so I can crawl underneath the shed and put fiberglass insulation underneath?
Either way I will be putting a barrier around the outside of the shed to stop pets/critters from trying to live in the fiberglass and to stop drafts.
Thanks in advance.
Replies
Greetings b,
As a first time poster Welcome to Breaktime.
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someones attention that can help you with advice.
Cheers
sleeps till noon but before it's dark...
bullclan,
In the event you fail to receive the information you desire, you might find it in the archives.
If you scroll down in the lower left corner of your screen there is a search function that will take you to previous threads dealing with whatever you type in the search bar.
If you type in 'floor insulation' or other keywords of the subject matter you'll get a supply of data from those old threads.
Cheers
r u a feckless dastard?
I don't understand what your shed foundation looks like. "concrete blocks on presure treated timbers" is a bit unclear. If we got a better idea of what the construction looks like from grade up to finish floor, I think we could give better answers.
In any case, 10x10 is pretty small (a decent size front loader could probably pick up the whole thing), so there are lot of options. Plus is doesn't get very cold where we live, so floor insulation ain't super-critical.
I'd stay away from fiberglass, as it loses all its insulative qualities once it gets wet. In an ideal world, you would have poured a 4" slab with some PEX in it, and 2" of XPS below it and around the footings. Then, you would have built your shed on that.
Given the exposure of the shed to the elements, I'd resort to XPS that is sealed in place. DowFoam and other makers make this stuff for underground applications, so it should be alright in yours, as long as the sun stays away. Given its high compressive strength, I think you have choice of using it from below or above (with sleepers, if above). I'd use 2" minimum, considering the stuff is R-5 per inch.
Edited 9/23/2005 8:22 am ET by Constantin
The foundation for the shed is concrete pier blocks sitting on top of two feet of compressed pea gravel. Between the pier blocks is pressure treated lumber. On top of the pressure treated lumber is a mix of pressure treated and fir 2x6 (I reused as much from an existing shed based when I built this one). The floor sheeting is plywood, rim joists fir (primed).I plan on putting pressure treated lumber between the siding a small concrete footing to keep out the weather/vermin with plastic on the ground as a vapour barrier.I like the idea of the XPS. The space underneath the shed won't get wet. It has two foot overhangs, gutters and a covering all the way to the ground (pressure treated plywood the touching ground). I realize I could simply not unsulate the floor as it doesn't get too cold, but without it the floor will get cold and this is going to be a space used during the winter, I would rather not wear socks...Thanks for the replies so far.
"applied a floating floor on top of rigid insulation either directly or under another layer of subfloor"
Did it in the barn shop, put 2 " closed cell polyurethane sheets Ply went in between 2x1.5 nailing spacers. Nice warm floor. (All items , insul and plywood, free at Boeing surplus free wood lot in Kent if you hit the timing right, a one time stop will not find anything probalby)
BTW, if you are in uninc. King county, you can now build 200 sq ft without any permit.
I will have to swing by Boeing surplus. I didn't know they had plywood and the like. I have to go to Fry's anyway ;-)It's interesting you bring up the 200 sq foot building increase as I have been toying with the idea of extending the building by 5' on one side (I do like in unincorporated King county). It is currently a shell (roof, siding which is painted, windows...) but no insulation or sheetrock on the inside. I don't know if it worth the effort for another 50 sq feet? I am going to be putting a lean too on the other side for bikes, lawn mower...