If you have a shared studded basement wall, I would be sure the insulation is Roxsul (mineral wool) which does not burn or retain moisture. Your point is well taken on spending up front to save in the long run. I always become a little suspect when somebody tells me how to do something when they don’t listen to my question. The higher R-Values (R 7.0 to 8.0) are the result of thermal resistance of the gases in the cells. Other than that I think you’ve done a pretty good job. Once you install 2″, you can frame a wall, then you can use fiberglass if you wish to get the desired R value. @ tnt – Sounds like a good detail. 3/4″ foam won’t do all that much to stop heat on a metal roof. FOAMULAR 150 2 in. I agree that you would lose benefit due to the non-continuous effect. My winter basement temperature is 50-60 degrees and I have had small, isolated water leakage problems a couple of times over 6 years when too much water got close to the outside walls (downspout problems). The insulation could extend into this volume. I’m insulating the attic on my 1910 craftsman in Seattle. I was hoping to leave the above ground walls open in the unfinished area of the basement for easier insect and mold inspection. Or have water get behind the foam more easily being that I will only be able to caulk it against the window extension jam. I couldnt put more than 1/2″ on without bumping out my existing windows and doors which i didnt really want to do as they were already aluminum wrapped a couple years prior. If so should it be house wrapped too? The required strength will depend on the foundation loading from your home design. Jeremy – I guess my concern would be the same one that I have for all basements. I am thinking aboutblue or pink foam board. Reflective bonus?….honestly not sure. Good point! Thanks, Bob. Then complete the rest with 1-1/2″ sheets. Yeah, my sump pump failed in the 2010 Greatest New England Flood of all time…Just my luck…I never had water before…. There are a couple of things that will help. FOAMULAR 150 2 in. I am planning to build a room over my attached garage. XPS is a closed cell foam board and a far superior choice for this application. Love it! I wouldn’t special order anything. Do I have to stud this out further somehow to get the thickness I need or be happy with some sort of foam insulation panel (Which type do you recommend) that gets me only a R-5 or so wall and will get this passed the building inspector and this is a permitted project. In addition we had a bit of snow brake left over so we installed three 4′ sections spaced 4 feet appart to make a permanently installed ladder on one corner of the roof to allow access to the peak. I see no need for a vapor barrier Kraft paper. No…just my preference. My scuttle can barely accept a 32″ piece of 3/4″ polyiso (1/3 of a 4×8 sheet). – One inch of foam board only provides a minimal insulating value. Any help would be appriciated. We are working on one of the rooms on the top floor (3d floor)we gutted everything and what is left right now is three brick walls. I forgot to mention that were in Ky which if very humid at times. My concerns with the project is what will make “code” vs. what is recommended. The bottom of the drain plane should have screen of some sort as you pointed out. I am looking for something to insulate the door for the winter and do not want to spend very much as it is a temp thing. You need to start with a minimum of 1-1/2″ of foam board. (any risks with condensation/mold between them?). Second question, I have heard of the do-it-yourself, blow-in insulation foam options. I have and old house with double walls built out of lath which was covered by plaster. Todd, been reading all this information and it has been great. So before assessing your proposed details I think you need to focus on structure and insulation values as they are all on the “low” side of what normal code would require. That’s how I’d probably approach your situation. I am in a similar situation where the rooms above garage become freezing cold. I tried pushing the insulation down into the corner but can’t reach that far down with my 3/12 or 4/12 roof very well. Alan – Blown in insulation is a great option for attics. Is the polyiso strong enough to support the weight of someone walking on it, if there is a some kind of covering? Hello, I am about to insulate my 4000 sq ft ceiling with 3/4 inch tyvek foam which comes in sheets of 4×8. It currently only has faced fiberglass batts which have been installed between the voids found within the truss, which is actually 2×4’s laid flat; only 1.5″ thick. Thanks Mel, Hi Todd, Well, after reading your reply, I got to checking I think I’ll go with R-13 Kraft faced for the walls and R-19 for the roof. Any suggestions? I need help!! @ Charlie – You’d be amazed at the difference 2 inches of foam on the walls can make. Thank you very much for your help! I then want to shingle the top sheathing so it matches the existing garage roof. Sometimes you do need to apply some temporary shoring but not often with this product. This doesn’t cause an issue for vapor barriers. I installed 1-1/2″ extruded polystyrene foam insulation board by DOW. I have an old 1920’s home with a brick exterior and plaster interior. You’ll have a tough time getting a good finish. Use Owens Corning® FOAMULAR® to insulate your garage ceiling / bonus room floor to effectively condition the space. Is this method sufficient? I’m building a home close to Houston Tx and have 2×4 walls, wrapped 100% with 1/2″ sheathing and then with 3/4″ R Max insulation boards (R-5). 80% plus. Todd–I am interested in mechanically fastening and gluing xps boards to a metal wall. Closed cell spray foam – works wonderfully, definitely most expensive option. Todd – I’m in the planning stages of building an earth bermed single story home. Will this work? How do you plan on using them? Keep it clean. I am planning on using foam board for a slightly different approach. I understand that it will certainly help with the temperature control in the rooms and I know it is recommended for that point alone but, is it against building codes to not install it as well prior to drywalling? Advice about installation appreciated. Jeremy – Yes spraying it in place will work. I have the picture, I just don’t have a email to send it to? I’m currently living in upstate, NY. If you tape it well the house wrap is probably over kill. Please lend your advise. 3. If you’re able to, find a contractor that uses CertainTeed Insulsafe or some other white colored blown fiberglass.