Can either of these boards come in direct contact with the roof sheathing if I seal it well with spray foam? Do you have a concrete wall that has rooms on both sides? If you get a 2″ or 3″ I went to Home Depot the other day to get an idea what types of foam insulation they carried. Of course, you should eliminate any leaks first but vapor WILL pass through concrete no matter what you do – therefore – let it breathe in order to avoid rot. Would you insulate or seal the block? You can even center the water flow toward a drain. They don’t have any detailed spec sheet touting any kind of advanced technology or features. Certainly worth looking into though. Good luck. I’ve never crossed this exact situation. for the foam, so this would be a huge savings if it will achieve the same effect. That would probably work pretty well. Thanks. The reason we often do the blown in is it can really seal things up very well when pumped into a cavity like that and packed full. I’d also recommend a small air gap between the framing and the foam if you can spare another inch, any room that allows for drying in case of moisture or water is a good extra step. View in gallery. 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 am looking to add insulation to the above grade bedrooms on the North side of the home. Gambrel roof. Otherwise, efforts to adhere insulation to the bottom side of the structure will be difficult at best. The slab will be radiant heated. You know the type that comes in those spray cans. First of all controlling the RH will always help in these situations. No vapor barrier. Michele – Not really, the real issue is being sure it’s closed cell foam. Concrete Block Wall that is drained from the inside (yes inside) of the house using weepers around the perimeter of the basement with Delta MS attached to the wall (up to ground level) which extends over the weepers under the basement floor. 1. I figure I could seal up the interior well enough to stop any air flow to the exterior using caulk and tape. Will the polyiso sheathing trap moisture in the cavity under it? I can’t find much information on it but I think if I attach the foam board to the runners, this would give me 3/4″ air gap/vapor barrier between the metal siding and the foam, the R factor for 3/4 is 3.2. T&G can be used but 1x typically doesn’t make that requirement. The concrete walls are poured. – 1.5″ air space from bottom of last Polyiso board to 1/2 inch or more sheetrock (heard this will give R3 increase)? 5. Do you think we should remove the plaster and glue the XPS boards directly on the brick or we should glue on top of the plaster? I live in North Carolina south of Raleigh? There’s no moisture problem, no mold found after removing the old paneling. If you insulate below the slab then some folks don’t actually insulate above. You can use the same methods we use for basements found here: http://www.homeconstructionimprovement.com/how-to-insulate-basement-walls/. It had 1/4″ plywood paneling over 3/4 furing strips on 24″ centers. been asking everywhere but not getting a good response. Will the polyiso hold up under the slab? Then screw 1/2″ drywall over it all to the furing strips. If the basement will not be finished I recommend a poly vapor barrier, properly taped and sealed. Also, we plan on keeping left over paint etc in a part of the area and don’t want it to freeze in winters. If you start going into AZEK trim, it will get expensive. You should spray it also on the finished side. Thanks Todd. Brian – is it curved? 1- Is there a specific vapour barrier that goes under polyiso? Your opinion would be appreciated. (I should have done 2×4, saved money and did foam board layer on the outside to prevent “thermal bridging” from the wall studs) But we are ready to start the cedar siding and the builder isn’t keen on adding layer(s) under the siding since the windows are in, tyvek is done, …) – he’s worried about moisture getting behind. I don’t want to spend the time and money on the XPS only to have the moisture barrier benefits negated because I didn’t address this space. (2×6 walls and 8/12 pitch roof- storage option in attic) However my husband really wants to do closed-cell spray foam (professionally installed). Go with the 2″ of closed cell and save yourself a lot of aggravation later. Ted – Great idea! I prefer XPS foam board on concrete. Polyurethane and isocyanate foams are applied as a two-component mixture that comes together at the tip of a gun, and forms an expanding foam. Most likely you’ll want to install a layer of foam board over the furring strips prior to installing the drywall. Where the old walls were taken down you can now see exposed areas of brick (there is no exterior wall sheathing beneath the brick in some areas). No real fire issues that I’m aware of (assuming you don’t have any fuel sources up there). The meeting of the ceiling & wall is curved, so that has to be taken into account. Heating won’t be necessary, just cooling. It seems the Dow blue or OC pink are the boards of choice but the only 2″ XPS that our local Lowes carries is GreenGuard and I was wondering if you think it would be worth special ordering 2″ blue or pink? I am planning to build a room over my attached garage. Prices range from $14.47 to 33.92, depending on the board thickness and r value (ranges from 3-10). But just to clarify, does the 2 inch XPS go on top of the footers as well as the gravel or does it go on top of the gravel but level with the top of the visible footer? We have a 400 sq ft sunken by 4 inches -section designed for the theater that Im concerned about especially with moisture since immediately upon digging-there was water pooling but eventually desipated but occasionally is there anywhere from 2-4 inches. Spray foam tops the list, polyiso would be next. a couple years? Anything less will result in moisture problems. It still has the original wood siding. Closed cell spray foam – works wonderfully, definitely most expensive option. Will heat with portable electric heat if need be. What I don’t like is the foil faced against concrete. Seems like going over the foam and using that as the extension would be safer and caulk the underlying furring strips well to keep them from allowing the moisture under the foam from penetrating. Just be sure to seal the joints well. Brad – I’ve seen up to 3″ thick DOW Foam Board. Can i just sister every second rafter with a 2×10? What will this room be used for? Hi, I am insulating our basement in southern Ontario. The batts could be a problem depending on the details. Many many commercial roofs are not unvented with 6″ of iso on top. Then drywall to the metal flange. I used a special Styrofoam adhesive to adhere the foam board to the concrete (you can also use “Great Stuff Pro” foam in a can). I was thinking of starting by installing closed cell foam board to the roof of the shed with spray foam around the gaps. 2a. We do not have access from the inside without tearing out sheetrock. What you would do if you lived here in Indiana and roughly how much would your recommendation cost? XPS does not absorb moisture; a 2" thick layer will provide R-10 insulation plus a strong vapor retarder. The new line includes 3 new models; DWE7480 - 10" Compact Table Saw, DWE7491X - 10" Table Saw with Scissor Stand, and DWE7491RS - 10" Table Saw with…. The whole point is to mechanically fasten and glue xps board to a painted metal wall without creating a thermal bridge. It’s reasonably priced, light weight and easy to use. Hold a thin piece of ISO up to the light and think about all those cell walls breaking down from UV damage. Copyright © 2009-2020 Front Steps Media, LLC. 2. I would just use 2×4’s or if code allows you may be able to use shallow boxes (if they will fit in the 1-1/4″ space you have. EPS, also known as beadboard is the third and cheapest type of rigid foam. Thanks for the kind words. I do not want to remove the attic floor to insulate. This can cause issues with windows and doors. Alan – Blown in insulation is a great option for attics. Evelyn – You’ve got me stumped. 1. It is over a bedroom that is on the North-East side of the house. Is there a better product I can get my hands on ??? I did put in a attic fan to help get rid of all that extra heat in my attic . Also, what do you recommend for our 2×6 walls? More is better…but it also has implications at the door and window trims. Thanks. Will this work for added insulation and will I run into any vapor problems? For more information, check out our, Basement Vapor Barrier For Basement Insulation, Rim Joist Insulation – Insulating Options, http://www2.dupont.com/Tyvek_Weatherization/en_US/products/residential/resi_seam_tape.html, http://www.amazon.com/exec/obidos/ASIN/B002KM1APU/homeconstimpr-20, http://www.homeconstructionimprovement.com/how-to-insulate-a-concrete-floor/, http://building.dow.com/na/en/products/sealants/gspwallfloor.htm, http://www.homeconstructionimprovement.com/basement-insulation-guide/, http://www.homeconstructionimprovement.com/how-to-insulate-basement-walls/, http://www.homeconstructionimprovement.com/certainteed-bibs-insulation-system/, http://www.facebook.com/pages/Home-Construction-Improvement/248544769916, http://www.homeconstructionimprovement.com/vapor-barriers-for-basement-insulation/, http://www.homeconstructionimprovement.com/basement-insulation/, http://www.homeconstructionimprovement.com, http://www.buildingscience.com/documents/profiles/etw-houston-profile, http://www.homeconstructionimprovement.com/insulating-cathedral-ceiling-with-foam-board/, http://www.homeconstructionimprovement.com/foam-board-insulation-vinyl-siding/, http://www2.dupont.com/Tyvek_Weatherization/en_US/assets/downloads/pdfs/K25107_Weather_Barrier_a_Must_with_Exterior_Foam_Sheathing_Tech_Bulletin.pdf, More Home Improvement Cost Savings articles », DEWALT Table Saws DWE7480, DWE7490X, DWE7491RS. 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