Use either cells or unfaced FG batts in the cavities. Furr as Mike sed, do the boxes as Mike sed. Therefore it must have a solid surface for successful installation and finish. It will be harder to get clean screw heads on the drywall … .. ok.. my new energy wall is now called  a "mooney" wall.....lets say the outside 2x4 stud bay is (R3.7 x 3.5" )  say R-13 , but it is degraded because 10% of the wall is stud (R1 x3.5") say R-4... so the 2x4 stud  section is a combined R-value of about R-12, and the combined R-value of the flat 2x3 is about R-4.8  say.. so the  Mooney wall would be about R-16... and a fiberglass 2x6 wall  ( R-19) would be a true R-17... but  i don't believe this accounts for edge loss with the fiberglass batts....so i degrade the fiberglass wall to at least an R-15.. NOW, our previous energy wall would be (R-12 ) + R-4 (foam) so that would be R-16 also, but the foam is an extra step, and extra money, and you have to fool with the elec. There are some studies that apply to roofing showing that a radiant barrier as compared to same insulation with no radiant barrier place a space away from the underside of roof sheathing will reduce attic temps but increaase the roof surface temps and reduce the life of the asphalt shingles.. There is no scientific or technical justification for John Clark's statement that "you could trap moisture … How to Apply Drywall Over a Rigid Foam Board on an Interior Ceiling 1. Consult the adhesive instructions for specific drying times. to secure the foamboard in place. The plaster had loosened to the point of falling off in areas. Seal adjoining spaces, if any, … This reflects a cost of $2.12 per square foot for walls and $2.35 per square foot if including the ceiling. Judgement for the plaintive in the amount of,........ You make it sound impossible to install 1-inch rigid foam over studs, and then drywall, without horizontal strapping. For a typical 12’ x 12’ room with a wall height of 8’, the price averages around $815 for just the walls, or a total of $903 if including the ceiling drywall. Squirt adhesive across the back of a sheet of drywall, using squiggly lines spaced every few inches. That airspace is equally important in warmer climates where ice dams are never a problem. However you may lath on top of the foam if it wins out and drywall from there. Re: Drywall over foamboard installation. Then cut out the section with a drywall saw or utility knife. A: I recommend keeping your work process as simple and clean as possible, and rigid foam can certainly help you achieve this. It won't create moisture issues. It works with most gravity-fed texture materials. Hanging drywall over top meets building code requirements, creating a fire-resistant surface that's ready for finishing. I think the penetration ends up about 3/8 with thinner trim than you mentioned and the nail head 1/8 below the surface. The white cheap foam will not as well as it will crush easily. I could become a professional student really easy ! Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine. Previous owner had replaced windows & re-dashed the stucco. It is behind steel siding, and the instructions said to face the foil side out. When done, use canned foam to fill the gaps between the sheets. I recommend 5/8 sheetrock walls and ceiling. Of course that changes everything doesnt it ? There is a soft product (ie) called Tuff R that would need furring I agree. General-purpose polystyrene is clear, hard, and rather brittle. Inch for inch, rigid foam offers higher R-values -- meaning better insulation -- than fiberglass. North buildings you want to reflect in. (I had walls separating the ceiling sections and was able to use long enough sheetrock to avoid butt joints). If you want to do things like putting foam on the wall with out furring then don't choose drywall. I have already had the siding off, when I replaced the windows. a"Attachment is the strongest block to realization"http://CLIFFORDRENOVATIONS.COM. Seems Im always running into something new and having to look it up and review it. DW wanted wider sills anyways. Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. If I did say lay 1/2 inch foam board over the ribs .. is it OK to leave the open gaps between the foam board and the roof? When the water started flowing from my ceiling, I caught 30 gallons in buckets. Closed-cell foam is a fantastic product, and I used it to insulate the floor of my outdoor shed. For what that's worth. Styrofoam Brand Residential Sheathing adds up to an investment that will pay for itself in just a few years, and continue to provide value for years to … That was my guess, but never having used it inside, it was just a guess. I have been trying to keep up with my job and going to school. fonz... we are talking about putting 1" foam on top of the studs , aren't we ? The big drawback, however, is rigid foam is highly combustible and emits toxic fumes while burning. wanted R-25 min. Gentlemen; I am redoing sheetrock in four outside walls, roughly 50 linear feet. Is that foil faced on both side? Lift the drywall in place, pushing into place against the ceiling and adjacent wall without forcing it tight. Excellence is its own reward! All that is necessary is careful, accurate installation of the drywall with long screws. Tape each seam with housewrap tape. Stretch the tape from the top to the bottom, without gaps, and over any other... 2. you may have to add wood where ever there are seams in the … Apply the foam board over the plank ceiling then, and then use a 16 nailer, and run cheap studs On 16 inch centers on your ceiling. 3" drywall screws will be used to fasten the 1/2" drywall boards through the 1 1/2" foam board … It's better to use proven methods then what sounds logical. Only after its hung on the wall does it actually cure to its hardness. Polystyrene can be solid or foamed. I decided that a total tear out would be easier to replace the wires plumbing and insulation. I had to do exactly what you described. Screw depth set is VERY  critical. You apply it facing the side you want heat sent to. FROTH-PAK™ is a chemically cured foam, which significantly reduces curing time, allowing it to dispense, expand and become tack-free in mere seconds. devices, and apply the furring... so , Tim, i think i like it... my new "Mooney wall"... here's the process,  frame the wall, nail 2x3 @ either 16" or 24" , install elec. Most drywall contractors hate installing drywall directly over foam, for the reasons you mention. Final result after taping; an excellant retrofit wall system. A screw every 16 to 24 inches apart on vertical and horizontal seams is sufficient. Put R12 fglass between studs & 1.5" white foam over top. I use plastic cap nails for installing the foam. Befor I knew better, I did the same thing myself. But many of us have done it. Piff..Trust me.I feel! Or make a shallow cut by repeatedly scoring the line with a sharp utility knife to begin a hole patch. Our most versatile foam, slow rise formula is designed to completely fill cavities without harming existing walls. Foam board insulation is easy to cut with a circular saw with a masonry blade or scored with a utility knife and snapped like you would drywall. There wood be a lot of people doing the same thing if it were a testament to fine home building. 2.5" shingle nails to hold foam & 3.5" screws through all to hold drywall. We use 2 1/2 & 3 1/2 deep switchboxes and make sure they are all secure and level- blocked, shimmed, screwed. Avoid products that do not specify safe for foam as they are likely to degrade the material. We have to stop when flush instead of driving the nail home , otherwise the siding wont be in a straight plane. It may be wavy if the foundation is not flat. Doors, for example;  I shim/screw the jambs 5 places each side centered under the stop. Since most fire codes call for a minimum of half-hour fire rating over foam insulations, paneling would probably not provide a sufficient fire barrier over the foam insulating board. My method? devices, plumbing, blocking,  apply Regal wall fabric & glue, blow dens-pak cellulose, hang the rock / blueboard... Mike Smith   Rhode Island : Design / Build / Repair / Restore. We shim the drywall recess at the floor and raise the BB up 3/8. Dimple the drywall surface slightly with the screw head to sink the screw properly. devices... and hanging your rock, and applying your interior trim... if you do furr, it will be more labor and money up front... but it all comes out in the wash...". The nail will bust through before indenting the drywall. We just used enough roofing nails to hold. October 4, 2016. You can use drywall right over the foam board and use tapcons to screw the drywall right into the foundation. Mark the wall in … It is needed for contacting water such as for underground or some prefer it for in roofs because of potential for water intrusion.. Down is changing the blowing agent on Thermax and respecing it at 6.5/inch. Polystyrene (PS) / ˌ p ɒ l i ˈ s t aɪ r iː n / is a synthetic aromatic hydrocarbon polymer made from the monomer known as styrene. We use blocking where needed for trim. On the foam with furring and drywall you have a 3/4" air space in there. You would have 3.5" to hang ceiling trim and base . Clear debris out of the hole and remove all pieces of drywall or plaster that are clinging to the edges … if the foamboard is firmly attached and FLAT, drywall right over it with screws into the furring strips. Or should I just use the fiberglass? That was a great description and fits all my experience with sheetrock and you've had more; however,  I MAY be talking about HARDER foam board than you are. It does do a little but I doubt it's worth thinking much about. The stool screws up into the side casings and the casing is bradded to the jamb extensions. It's easier to add backer board than to try to cut the drywall over studs as you learn how to fix drywall. The foam board will first be fastened to the 2x4 studs with nails that have a large plastic washer. Builder’s Advocate: An Interview With Viewrail, Plus, get an extra 20% off with code GIFT20, Simple Way to Make Old Walls Straight and Plumb, Expert insights on techniques and principles. R-4.8 1.25-in x 1.6875-ft x 8-ft Garage Door Insulation Kit Faced Polystyrene Garage Door Foam Board Insulation You can then put your drywall up. Andy"Attachment is the strongest block to realization"http://CLIFFORDRENOVATIONS.COM. Tack it up with just a couple of nails w buttons. I am guessing that it is radiant barrier on my building. No outlets, one window. This is in northern new england. Obviously you can't get R-25 in 2x6 (with fiberglass). it has double the R value per inch as the pink or blue. And with the horizontal furring you won't have much in the way of convective air currents. tim... this is as good an excuse as any.. how are you doing?.. Drywall gets screwed to the furring strips. the foil stabilizes and protects it for handling and installation and is a vapobar. I know you guys know your stuff. Mike;  I have  a dumb question. Simply drill and fill behind the drywall or plaster – ideal for retrofitting older homes and buildings. "I have learned so much thanks to the searchable articles on the FHB website. We use gages for depth. The problem with that application has always been that the foam board needed to be covered with a “thermal barrier” or “flame spread barrier” like drywall in order to meet local fire codes. Demand for rigid foam insulation has increased exponentially in the last couple of years. Tape seams with foil tape. I was beginning to think I was on an island by myself. Blue board is speced 5/inch. Adding interior rigid foam over the existing drywall is fine. Learn more about affordable, modern floating stairs, from design to manufacturing to installation. 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