Hi Todd, I am very confused and concerned. Last question is assuming that we will place the 2 inch XPS uder the concrete, do you still recommend something to place below the wooden studs so that it is not in contact with the cement floor? It does come at a cost, more money to build, needs exterior finish (stone, brick, stucco) for the exposed portion, and the interior needs to be finished in order to protect against fire. But opting out of some of these cookies may affect your browsing experience. For the detail at the top of the wall and into the joist cavities, do you run a horizontal piece of insulation between the top of the wall and bottom of the joist cavity so that it’s continuous, or do you just run the insulation to the top of the foundation wall, put the pieces in the joist cavity, and leave a gap? John – Sounds fine, lots of roofs are insulated in that fashion. The R-30 rolls would measure about 9.5 inches wide (when stacked vertically). Have you spoken to your building code official yet? Why would you attach felt paper to foam? Ryan – I would recommend using foil faced polyiso under the siding. Good luck. Again, you’ll need to check this to the document above and also local insulation contractors. Discount Construction & Roofing Adhesives. Otherwise it’s likely to absorb moisture and eventually mold. Hello, I am about to insulate my 4000 sq ft ceiling with 3/4 inch tyvek foam which comes in sheets of 4×8. No real fire issues that I’m aware of (assuming you don’t have any fuel sources up there). It is completely sealed off. My basement seems damp in the summers so I have to run a dehumidifier. The attic is a conditioned space, it’s a 1.5 story home with the room-in-attic addition and I will be building gabled dormers in the middle of the roof line on each side of the house that will take up about 1/3 of the total roof area. thanks. I think I’ve talked myself out of using the 3-4″ iso. If it were me I’d go with 1-1/2″ of foam board and call it good unless there’s a more specific code issue. Gambrel roof. DIY foam is really difficult and not something I recommend. If you do it this way, I agree with Todd, because you are going to incur a higher cost of labor. Not sure if it was ever insulated, but I was thinking of applying 1/2 foam (probably Polyiso) directly to the plaster of the interior of the inside walls, then dry-walling or using a new plaster that sticks to foam, over it. The contractor is offering Procanna siding for the color I want whioh seems to be OEM’ed from an Ontario siding manufacturer, thickness is .044 and 25 year fade resistance. Then go ahead and frame with 2×4 with R11 fiberglass insulation. Will the foil act as a vapor barrier or will i need something additional? ft. Do you think we can do away with just one 1 1/2 inch foil faced board with the foil facing towards the room? And obviously there are cost issues. They clearly weren’t eating it (there must have been something much tastier in that wall), but they certainly chewed it. Anything short of this and you’ll have serious moisture and mold problems. House is in New England. If so, I’d probably use some PVC decking material or PT lumber. One of the top manufacturers is Carlysle. Polyisocyanurate also known as polyiso is seen in all kinds of commercial building applications and more recently with residential building projects. Closer investigation revealed carpenter ants emerging directly above and dropping off their cargo, chewed out from the inside of this insulation. I plan to install sheetrock attached to the furring strips. What is the best way to accomplish this???? Question: Can I install Extruded or polyisocyanuarate between the studs for my insulation needs then cover it up with 1/2″ sheetrock. “Floating Slab” actually implies that you let the slab move up and down with the frost. The finished side is actually the upper pitched end of a living room with a cathedral ceiling. I live in a 2nd floor north west coast condo and one external wall in the condo is poured concrete (i believe) and is insulated with well taped pink fiberglass and then covered with vapor barrier and then drywall. 2. I figured I would use earth tubes to prewarm the air before it enters into the heat exchanger. Thanks for sharing! If you’re going to use foam board, then be sure each layer is sealed to the joists VERY well. I am purchasing an old house in Louisville, KY. Hello , i would recommend an Air Barrier anywhere but floors , and preferably closest to living space as possible , lets not confuse Air barrier with vapor barrier … We need to protect the structure from all the humidity generated inside a home …ie each molecule of air in a home normally has 45% to 55% water . For this application I would recommend at least 2 inches of foam. It’s used in commercial construction all the time. Please feel free to contact me if you have any questions, suggestions or you'd like to inquire about advertising on this site. Sorry I forgot to tell you that I am on the southern Oregon Coast. Built around 1900. Then you can add more foam or supplement with fiberglass. Good luck. My goal is to raise the floor temp of that room and decrease my energy bill. External applications should always use Closed Cell ISO. Brad – I’ve seen up to 3″ thick DOW Foam Board. Maybe you're considering having a new deck or fence built. 3. Not all is lost if you can’t do this, the heat will still heat the slab/rock and radiate heat from the surface. The average cost of flat roof insulation is $0.67 per square foot (for 1 inch thick PolyISO with 6-R value). Rigid panel insulation also referred to as continuous insulation, can be made from foam plastics such as polyurethane (PUR), polyisocyanurate (PIR), and polystyrene, or from fibrous materials like fibreglass, rock wool. Thank you in advance. That’s the idea. Moreover, roofing suppliers don’t quote it for small jobs. Doing this showed me that there was no insulation and I’d like to add it. Most of the foil faced products are covered with foil on both sides. Would this setup cause moisture problems? This room only has 1 wall that is above ground. As you know it can get extremely hot in the south. Fiberglass is fine after the minimum foam. 2- How to fix the polyiso on the vapour barrier? Also it is much more expensive. Without going into a huge long dissertation I’m asking for some help from readers. I lifted my house 7′ and framed a wall from the existing foundation up to the new height of the house. Is this your experience? Pat – You certainly could do that but you need to check on the fire rating of that assembly. Tom – I’m not sure that method will work very well and here’s why. I think if you’re using batt insulation, with a vapor barrier, I’d probably NOT tape the foam. Hi Todd- I’m building new construction in the fall and was wondering what your thoughts were on an ICF basement vs concrete block. eric. Any time you tear off a roof it’s likely you’re going to invoke some new code provisions. Make sense? Good luck. Todd, I am remodeling an old farmhouse in Pa. Say 4 inches of solid EPS insulation stacked in a wall, then sealed with can foam (prior calking any sills and opening to prevent any air). Or maybe even put fiberglass beneath it? First let me address the foam type. 4. Here’s a real quick thought of mine on these sealers (also let me say that my Master Degree research was on concrete material science so I know a bit about concrete). I’d use the same approach on the walls. Good luck. If you’re able to, find a contractor that uses CertainTeed Insulsafe or some other white colored blown fiberglass. Having said that it really comes down to how much “space” can you allow for insulation? It won’t really amount to much other than sealing out some air infiltration. Will a vapor barrier keep the moisture out or will I have to use a de-humidifier? I am renovating it and just took down the plaster and lathe. Second question, I have heard of the do-it-yourself, blow-in insulation foam options. I just found your site, and like the posts. Todd, What do you think about the do it yourself handi foam closed cell kit? These cookies will be stored in your browser only with your consent. Small gaps are hard to deal with. From reading other posts I think I should use 2 inch XPS foam sheets (or closed cell spray foam) directly against the concrete and then drywall with nothing else. So the Tyvek plus the tape sealed foam would not inhibit the wall’s ability to breathe. I’m refurbishing a 1950’s finished basement in Seattle. Thank you so much. My garage walls are insulated and so the roof by the builder. I’d start off by checking with your local building inspector to find out what the minimum (if any) required insulation value is. I recently raised my house because of a high water table in the area. I have a dehumidifier. Since the lower level will have the bedrooms and the concrete slab will be polished and left exposed, we want the floor to be as comfortable as possible (no radiant only heatpump(s)). I also need to cover some voids created by dropped ceilings over the kitchen cabinets (unless it’s ok to simply fill them with the blow-in). There is not a lot of headroom, and since it will be livable space, I don’t want to bring the ceiling down too far. You can read about insulating a floor here: http://www.homeconstructionimprovement.com/how-to-insulate-a-concrete-floor/, Tood We are going to reside with vinyl siding on an older home with 2×6 framing that has fiberglass bating insulation inside. Part of the basement is above ground and was insulated with fiberglass. A savings of $2400/year would pay for about $48,000 greater expense in construction. Soffit vents will be blocked and the space will be turned into an unvented attic. Not sure I understand your question. Then installing 2×4 walls with a PT base. Maybe I will have to get someone in China to make it. I building a new home in Ontario and will be installing hydronics in the basement floor. If you install the foam board behind your wall then there is no need. Joe – Using foam inside the cavities is a fine idea. Your proposal seems solid. The difference being your elimination of the ‘sealing’ part provided by the 3/4″ iso board, which I thought would help as I’ve noticed that some of the horizontally blown in stuff seems to have been blown around at least in one nearby corner, which is at one end of the truss I’m trying to insulate. Rigid board insulation is simple and easy to fit, and come in a wide range of different materials, sizes and thicknesses, to ensure you can find the most … Alison – Can you be more specific about your questions? Wherever EPS touches Wood you will eventually have mold, mildew, and rot. My feeling on these products is they certainly won’t hurt, but they don’t really provide all the protection that some folks think. If any damp air gets into the wall cavity it now has the chance of that vapor turning into liquid condensate. Questions from top working down: – 2″ air space between sheathing and 1st Polyiso board for ventilation from eaves to vented cap, any moisture issue? Insulation contractors have been blowing cellulose into wall cavities for years. Though I must admit I’m still not positive over existing drywall is acceptable, though much easier than tearing it all out! No…just my preference. Foam Boards. If the stairs will slide on the landing I may try to move. There are more and more folks spraying a thin layer of foam inside the cavity followed by fiberglass. The company I work for bought a large commercial building. There’s no moisture problem, no mold found after removing the old paneling. Any help would be great. The outside concrete wall is painted on the outside only. Thus, you want to have a high r value, which is achieved by getting thicker insulation. The eves are always tough especially on a house with shallow rafters. Anna – Are you doing this in an unfinished attic? In summer this room is boiling and in winter it is frigid cold. I caulked and sealed the seams with tape. Thus, a 0.5 – 1.5 inch board would cost about $80-85 per 100 sq.ft. I agree that spray foam is probably over the top for this space. I Have a small 900 sq ft single family house with a walk in cellar in the Boston,MA area. One of the best ways I see people do this is building a hay bale wall around the base. I have three questions (1) can I use Polystyrene / Polyisocyanurate Insulated sheathing (1/2 inch or 1 inch) to on block (2) have French drain & sump-pump, it gets busy when rains, any special suggestions (3) do I have to put framing and insulation, and drywall??? 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. The insulation is not consistent and looks dirty in places that I can see (where the original wood is broken). The required strength will depend on the foundation loading from your home design. There is no duct heating in this room and it will be closed off. Jazz – I’ve never heard of them but doesn’t mean the product is bad. I am thinking of using 1″ Dow Tuff-R blue board with R vlaue of 6.5. The sun gets pretty hot and I was concerned if the insulation got to hot and dry day after day it might combust. I am sorry about all the questions. I started to put up 1″ XPS when I found your information. Thank you for any advice you can offer. will there be problems with foam (summer heat, direct contact with metal roof)? Then built stud 2 x 4 walls. Recently purchased a 4 level, approx 3000 sq ft home with a sandstone exterior in upstate NY. I will say that if you think it’s worth the cost then it’s certainly not going to hurt anything. The ones I saw appeared to be constructed of a thin wire stud covered by a barbed plastic sheething. The upper 2×4 walls have lots of small cavities in the framing betweeen and above the window. So 6″ ISO would cost you about $2.75-$3.50 per sq. I’ll be using it as an RV. Thanks. First of all I would strip the old siding, fix and damaged sheathing and then install a layer of housewrap. 7. 1. I understand your specialty is cold climate. Ok, I am reporting back for the benefit of others who may be having this problem. 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