The vapor barrier would be a 6 mil poly that I was thinking of using. Or do you mean siding that was later covered with a second layer of siding? Thanks again for the helpful information. In south Georgia (climate zone 2), a ceiling should be insulated to at least R-30. Spray foam is particularly effective at reducing air movement through openings, holes, cracks and crevices. Amanda, I'm assuming that omitting the 6 mil allows any moisture in the wall to dry out so to speak. Finally, one manufacturer -- Johns Manville -- has approved the use of flash-and-fiberglass with its spray fiberglass product, Spider, including on sloped ceilings. In summer, almost all moisture movement is from outside to in, particularly when the sun is shining on wetted surfaces or saturated reservoir materials. Residential and commercial spray foam insulation for homes and businesses in Decatur, Alabama, differs from more traditional blown-in or batt insulations. In winter, most moisture movement is from inside to out, though liquid water can diffuse inward at the same time that water vapor is diffusing outward. Closed cell effectively tops out at about an R25 even when installed at thicknesses that should have a higher rating. Spray foam insulation installers in Chattanooga are can offer a home ... layer before laying down siding or drywall. With 2 inches of Spray Foam we believe you can eliminate 95% of thermal transfer into your basement walls. low air permeance If the roof assembly is unvented (probably), then it's important to allow a drying potential downward, which means an air-sealed but vapor open ceiling. There has been alot of chat on this site lately about this topic. What are you using for sheathing under the WRB? You must be a magazine subscriber to access this feature. Looking for an approved, ASTM test or a supplier of spray foam/ fiberglass/ cellulose who has gone through a testing proceedure that provides evidence that the combination of spay foam and fiberous materials do work together and have shown to do so over the lifespan of the home. Open Cell Insulation. Doesn't this potential moisture issue only apply in cold zones? Amanda, … To insulate the underside of ceilings. The recommended minimum resistances or air permeances for the three components are listed as follows: Material 0.02 l/sec-m² @75 Pa (0.004 cfm/sf @ 1.57 psf) – 25 mph equivalent It seemed to have worked very well, but for the money, was wondering if there's a better system. I should have explained it a bit better - the Owens Corning EnergyComplete foam is only a very thin layer of open celled foam that's intended to air seal the cavity, not to insulate. OC recommends (naturally) blown or batt FG for insualtion. Spray foam comes in two flavors, open cell and closed cell, and provides both parts of the building envelope - the insulation and the air barrier. Actually, moisture movement in and through building envelopes can be by: The siding is 1x12 white pine boards over 3" pine battens with a 3/8" gap between boards. (Here is a study done by the NAHB.) Yes, foam board insulation is an excellent complement to batt insulation. My insulation palns are to spray an 1" of closed cell in the exterior wall cavities against the lap sheeting. Any thougths? Hence why existing homeowners are moving to Spray foam insulation as it is a far more superior product and also lowers their energy bills and save money. Also, this is for flat roof construction. If money wasn't an object, which it is, what would be the best way to insulate your home? Thermal bridging throw the studs acts like a radiator transporting heat through the wall. Robert, Spray Foam Insulation Vs. Fiberglass, Batt & Cellulose. Basically I'm looking for a somewhat equal substitute for sprayfoam since it's a pricey option. Tyvek, Typar, and other plastic housewraps. My spray foam supplier says this is a safe practice, but after reading a few of your posts i'm not so sure. Thanks for the good information. 2lb foam has great qualities but I have seen it break away from the stud bays and leave 1/8"gaps, especially after the house has settled and after the wood studs have dried out. seal at all penetrations You give up a little R-value, but the wall can dry to both sides and thermal bridging is reduced. Then I read an article on Buildingscience.com http://www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems that omitted the 6mil poly. Can anyone explain this to me better or point me to more information. Blown in Cellulose. As long as the sheathing is somewhat vapor permeable, however, this isn't necessarily a problem. resist seismic, thermal, swelling, shrinkage and creep movements Framing hip roofs is one of the more difficult tasks in carpentry. No moisture problems yet (let's hope it stays that way). A poly plastic layer and sealing is needed to provide an air/vapour barrier; this barrier stops air and moisture from entering one environment to the other (indoors to outdoors / outdoors to indoors). That confuses me. I can't seem to find any studies or reports that are un-biased. It prevents heat transfer; reduces the likelihood of mold; and increases the energy efficiency for your home. Here are four reasons flash and batt can be a great insulation option: Structural strength. INSULATION. Michael, Many companies have come on board with these methods but don't have testing to back it up with. There are other examples as well. It can potentially replace the vapor barrier and house wrap as well. Mike, Since the batts do not naturally provide an air seal, it’s necessary to install a separate air barrier to do the job. The construction of the house, in Sedgwick, is chronicled at: http://thebarnproject.blogspot.com/. One of the key attributes of spray foam insulation is the capacity to seal a space airtight. Are all vapor barriers also air barriers, but not vise versa? and speaking with two insulation companies I am considering filling the walls with 1" of closed cell and then filling the remainder with blown in cellulose. Spray foam in the inside does not eliminate thermal bridging. The return on investment for the insulation cost of spray foam could see payback in as little as three to four years depending on the size of the home, location, whether the whole home or just specific areas were insulated with spray foam, and the potential savings achieved. In your climate, you don't have to worry about cold-weather condensation problems in a flash-and-batt installation. A thin layer of open-cell foam is quite vapor permeable. At best, they can constitute an air barrier material, but must be incorporated into a full 2D assembly and 3D enclosure. Any existing batt or roll insulation in the attic should have the facing against the attic drywall floor or … Would I even require the Ty-Par since the foam board would provide protection? If you want help with or more information about the issues we blog about, then let’s talk. Vapor-retarder paint is definitely not an air barrier. If the roof assembly is unvented (probably), then it's important to allow a drying potential downward, which means an air-sealed but vapor open ceiling. Fiberglass insulation is porous and susceptible to convection and wind washing. However, given the priority that air-tightness has been given in energy-efficient and durable construction, simply spraying foam in the stud (or rafter) cavities will not constitute an air barrier, since much air leakage occurs between foundation and sill and between floor decks and wall plates. What I don't know is how the extra insulation and the siding affect the propensity for condensation to form on the interior face of the exterior sheathing. The idea is to lap and tape all seams so the house is watertight before the siding is installed. Thanks Martin. By chance any moisture that gets in needs a way out. The colder the climate, the thicker the spray foam must be. Yup, there are as many reasons to avoid the use of petrochemical foams in a house as there are promotional claims by manufacturers and installers. As an overall system, I'm thinking of the foam board on the walls, the sub floor is going to be Dri-Core to allow air flow beneath, then 2x4 framing on top of the dri-core against the foam, then top that off with the Roxul to obtain an R23. inflexible Mike, Not all vapor retarders are air barriers. An effective air barrier must be continuous around the entire 3D building envelope. One would naturally need to tightly seal any seams or gaps between or around boards. Spray foam and batt insulation combination, http://oee.nrcan.gc.ca/residential/personal/new-home-improvement/choosing/insulation-sealing/basement/khi-inbasement.cfm?attr=4, http://www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems, Misleading Energy Reports Used to Sell Spray Foam. home that the ceiling and walls have been gutted to their true 4" depth. Robert, you said be continuous along all 6 sides of enclosure, Some materials that are not air barriers by this standard include: Thanks, Fernando, uncoated concrete block Michael, you really should have started another thread rather than hijack someone else's. Just type "flash and batt" in the search box and do some reading. Spray foam insulation for both types starts at about $1.50 per square foot and can cost more than $5.00 per square foot when a thick application is applied. The building envelope should completely surround the conditioned space, and the insulation needs to be in contact with the air barrier. Two critical items for the flash-and-fill or flash-and-batt system though: the foam has to be thick enough to prevent condensation 99% of the time, and you can't have poly sheeting inside as a vapor barrier--you need the airtight drywall approach instead, to minimize vapor migrating into your wall cavity but allow it to dry to the inside. A Look at Spray Foam Insulation. Unpainted drywall. Kraft facing, as usually installed, is a vapor retarder but not an air barrier. Yes, dry to the outside is my only real option. Don't feel bad that it required a sawzall. Air Sealing. This should dry quickly with a 7/8" air space between siding boards and sheathing. The vapor retarder on top of or between layers of insulation can trap moisture. The insulation industry has always been cut … Thank you so much. 2. I'm also planning on covering the interior studs with 1" foil faced rigid insulation before the drywall goes on. I would recommend keeping it as vapor permeable as possible, and make sure there is a good WRB properly integrated with flashings between it and the siding. As you correctly guessed, closed-cell spray foam installed against the wall sheathing lowers the vapor permeability of the exterior side of the wall assembly. By any chance, do you mean "lap siding"? Likewise, where should you not use expanding foam? To insulate the exterior side of the above-grade walls. In your climate, it will work -- although the resulting R-value won't be particularly high. resist displacement under pressure How does all of this apply to Zone-2 (south central texas). Of course, any GBA readers with experience are invited to comment. Because of the controversies surrounding minimum foam thickness, Johns Manville has NOT published a table showing minimum foam thickness requirements for different climates. The most important issue: be sure the foam is thick enough for your climate. Fiberglass installation labor cost is about $1.00 to $2.75 per square foot based on the amount of insulation and the location. This plastic insulation goes on as a liquid and expands to fill the available space, sealing all gaps and cracks and stopping any air leaks (This can also keep out bugs or other vermin). Although I called flash-and-batt "controversial," I think that such an approach can work quite well, as long as some basic guidelines are followed. I'm a few weeks away from insulating my new house on the coast of Maine, zone 6. Mark, Sorry, I meant to title this Spray Foam and Batt Insulation. But you're correct to notice that the Owens Corning marketing demonstrates bias and misdirection (such as comparing spray foam to latex caulk for air sealing). First, you should know that there is some controversy surrounding this practice. From everything I've read on this site, it sounds like foil faced rigid insulation to the inside and a breathable cavity to the exterior makes the most sense. 1. It also forms an air barrier, which can eliminate some other weatherizing tasks, such as caulking. To insulate the inside of the above-grade or below-grade walls. It's a technique used by some insulation contractors where a flash of closed cell spray foam at 1- to 2-inches is applied in an effort to create an air seal and then puts fiberglass batt insulation over it. So-called "flash and batt" insulation works, as long as the spray foam is thick enough. INC (401) 333-4170 (401) 349-4171 (Fax) (401) 231-4103 (Office) george@crossinsulation.com. What do you mean by "8" lap siding or sheathing on the studs"? Many building scientists would answer that it doesn't have to be -- but you should be aware of the controversies surrounding the issue before you proceed. If the interior is air-sealed with taped, foil-faced rigid foam (and all penetrations sealed), then the wall assembly needs to be able to dry to the outside. Spray foam kills mold on contact and reduces future mold growth Foam insulation is not a food source for mold, roaches, or termites Foam insulation is not damaged by water or floods Spray foam does not settle or pack down over time Moisture movement is through 2 methods bulk/liquid (a leak) and from vapor. Using polypans and the air-tight drywall system over a cross-hatched wall can be an easier way to get a good air seal, reduce thermal bridging and increase wall R-value. Put enough foam board for your climate to eliminate the potential for a dew point in the wall. Spray Foam Insulation. I shied away from applying closed cell foam boards to the exterior of the sheathing because it would present fastening issues for the siding. Spray foam creates an air barrier and insulation barrier at one time. Assembly 0.20 l/sec-m² @75 Pa (0.04 cfm/sf @ 1.57 psf) – 25 mph equivalent John, I have a 110 y.o. I am confused about the vapor issue between closed cell and cellulose blown in (to the inside) - There is no venting - do I need it? Amanda, I've been reading about flash and batt and wondered about the condensation issue. Hygro-thermal energy and mass flux is a very complex set of interrelated forces, resistances, storage capacities and vulnerabilities. I was basing it on the following article http://oee.nrcan.gc.ca/residential/personal/new-home-improvement/choosing/insulation-sealing/basement/khi-inbasement.cfm?attr=4 since I am in a cold zone. If you have access to a good academic library, you might want to look up an article on the topic in the November 2007 issue of Energy Design Update. Basically, you've got it right. If you depressurize a house with a poly vapor retarder with unsealed seams, you'll see how the poly does not act as an air barrier. - water vapor, driven by temperature or vapor pressure gradient, including radiant solar drive A typical ignition barrier is ¼” plywood installed over the foam plastic. yes it is a 110 year old home with 4" cedar siding on the exterior tar paper then 8" lap siding or sheathing on the studs. Thanks again for the help. You can read building science screeds on various systems in various climate zones for some perspective on this, but ultimately there''s no way to judge a particular system without understanding the complex and interdependent thermal and hygric mechanisms and forces that interact within the entire building envelope and interior conditioning system (as well as with the occupants). (416) 860-6664 [email protected] ... but the batts are also stiffer so they don’t bend over as easily. Spray foam insulation costs $1.36 to $2.63 per square foot to install, and blown-in fiberglass insulation costs $0.40 per square foot to install. Then the use of a plastic vapor barrier is not needed and SHOULDN'T be used. Batt fiberglass features tightly woven glass strands that come together to create a matrix. A DIY approach to fibreglass may be tempting, but a professional insta… The spray foam will do a good job of air sealing, as long as it is carefully installed. In retrofits, it can be used to contain any blown insulation or to support batt insulation. P.S. 2. Spray foam insulation is substantially more energy efficient and does not lose R-value for its 80 years of life. Foam board on the outside will prevent the thermal bridging. This was, of course, necessary in order to market such a nearly useless and dangerous product and to dominate the insulation industry as long as they have. With fibreglass batts, creating an airtight seal requires additional work. One other idea you might consider is the cross-hatched wall, where you run 2x2 strapping across the inside face of the studs and fill the whole thing with dense-pack cellulose. The EnergyComplete foam vapor permeance is listed as 40 perm (dry cup) and 110 perm (wet cup) on the data sheet. Don't assume that any opinions expressed here are unbiased. I love the Blue Hill peninsula. There are unscrupulous and/or uneducated contractors in any trade and spray foam is no different. Two inches of closed cell foam in a 2 inch by 4 inch wall can increase the racking strength more than 200%. I am also spraying an 1" in the rafter bays and soffits to seal the attic where I will install my air handler. CLD, (Assuming, of course, that your basement doesn't suffer from existing moisture problems.). Is there a better way to set up this application to avoid moisture infiltration? How does the building inspector assure the material is an air barrier? Spray polyurethane foam is a chemical product that is created by two materials, isocyanate and polyol resin, that will react with each other when they are mixed and will expand up to 30 to 60 times its liquid volume as it is sprayed in place. You're right. I have a question about using foam board insulation along with Roxul to up the R value. The fiberglass industry, particulary Owens Corning, has a long history of deliberate distortion - particularly in regards to cellulose insulation, which they attacked with ferocity for decades. WRB is "water resistive barrier," and it is usually a building wrap such as Typar. I boarded the house the old fashioned way with 1x12 pine on the diagonal. Susan, Blown Cellulose. Or is it more complicated than that (some things are one or the other, and some are both)? Since the thread's already been hijacked once, I hope no one minds if I do so again, to direct a question at Robert :). Will i be creating a water vapor trap between the spray for and the batts? transfer of heat is slowed down with fiberglass insulation because the glass fibers trap air bubbles The next step is to deal with vapor. According to the Air Barrier Association of America (http://www.airbarrier.org/index_e.php): Air barrier systems typically are assembled from materials incorporated in assemblies that are interconnected to create enclosures. Has a nationally recongnized testing agency done any testing on the "Flash & Batt/blown" wall or ceiling systems. perforated house-wraps You're describing a typical flash and batt job. Thanks Martin. Learn More, How Continuous Insulation Helps You Keep up With the Energy Codes. Thank you so much for such a detailed answer! Most insulation contractors use closed-cell foam, not open-cell foam, for flash and batt installations. To be on the safe side it sounds like I should spray 1 1/2 inches of foam. OSB and plywood transport and store water differently. VENTILATION. Flash and batt is a combination of spray foam insulation with fiberglass batts. The foam product uses for this insulation service is composed of an inert polymer. Halo Interra foam board insulation is applied to the underside of the ceiling joists. No insulation system functions in isolation and so a standardized test of insulation, whether homogenous or mixed, does not tell you how it will work within the complex hygro-thermal system that comprises a house, nor how it will work in a given climatic zone. What are your thoughts on that system in this context? Here's Eco Spray Insulation experts guide to batt insulation in 2021. Martin, On another direction. So-called "flash and batt" insulation works, as long as the spray foam is thick enough. Remember, many spray foam operators find it difficult to achieve a uniform spray of 1 inch. Here are four common applications of effectively using Halo foam board insulation in combination with batt insulation: To insulate the inside of the basement or foundation walls. Mark, As long as you omit the "vapor barrier" (I assume you mean polyethylene) on the interior of your proposed wall assembly, the wall should be fine. Even polyethylene is not an air barrier unless the seams are sealed with Tremco acoustical sealant or tape. Although I have no direct experience with the system, I have no reason to believe that the Owens Corning EnergyComplete system won't work well. Thanks for the input. durable, And must be able to: Batt fiberglass has been used more extensively than spray foam throughout history and it still holds up as one of the most affordable and reliable options. I recently used cellulose in the walls and used 5 1/2" of open cell foam on the bottom side of the roof deck. I thought I recently read an article on the Building Science website talking about problems installing batt insulation over spray foam – moving the dewpoint to the spray foam layer and causing the batt to get moist where it meets the foam. In all of the cases I cited, the materials still function as effective vapor retarders -- even though they leak air. Can you explain? With open cells, the cells are broken and air will actually fill the gaps that they leave. It’s a technique used by some insulation contractors where a flash of closed cell spray foam at 1- to 2-inches is applied in an effort to create an air seal and then puts fiberglass batt insulation over it. The spray foam gives me the tight seal and an R-3 and the R-13 batts give me whatever they are after being compressed 1/2 inch. Just make sure you do a good job with your air barrier so the wall cavity insulation can perform properly. You have an additional problem with a flat roof: coming up with a way to ensure that the batt stays in physical contact with the foam, without an intervening air space. 2) We've started to have some clients show interest in using Owens Corning EnergyComplete spray foam (http://www.ocenergycomplete.com/system/) to seal the wall cavity, then blow in cellulose/fiberglass. Two layers of rigid insulation creates a more tortuous path for air and vapor leaks. Even with carefully-taped seams on the foam board, you still have to deal with difficult-to-install and difficult-to-seal electric boxes that must extend 1/2" beyond the surface of the foam board. Halo® is the Advanced Graphite Insulation System that's designed perfectly for specific applications. Mark, If it's permeable, installing foam on the inside of the studs would be your best bet because you reduce thermal bridging and the assembly can dry to the exterior. I'm not sure what you mean by "lap sheeting." I'm in a dry/hot zone and I'm primarily dealing with baking temperatures on the roof surface. If you tell us where you are building, we can provide recommendations on the minimum foam thickness. Spray foam (or spray polyurethane foam) insulation is more than just a layer of insulation; it creates an impermeable barrier for moisture and air without the need for a separate vapour barrier. However, I have doubts about the ability of a "very thin layer" of open-cell spray foam to create an effective air barrier. Blown in Fiberglass. Yes, foam board insulation is an excellent complement to batt insulation. Learn More. © 2021 The Taunton Press, Inc. All rights reserved. With the flash-and-batt approach to a cathedral ceiling, the batt is under the spray foam, not over the spray foam. Now I can’t find it anywhere and am wondering if I understood it correctly. That can be tricky, unless you stuff an oversized batt into a tight cavity. OK, I got it. Whether it be batt, blown, spray foam, or blanket, removing old insulation is often mandatory to reduce risk of exposure to older harmful materials. That's not enough. I am currently renovating an old home is south west iowa. separate spaces with differing temperature or humidity regimes Fiberglass Batt Insulation. After reading much. Furthermore, you have now raised an additional question: should the roof sheathing be vented? My home is in the northeast of the U.S. Any spaces and gaps that aren’t filled can equate to the size of a basketball, with enough air leakage everyday to … The minimum spray foam thickness depends on your climate. I'm in South GA if it's relevant. Would this allow for enough drying to the exterior? While this is understandable, I was interested in some non-biased opinions of the potential effectiveness of the products, which you provided. It's for my basement and I am planning to put up Ty-Par against the concrete block foundation, then install 2" thick foam board, then frame with 2x4 and install Roxul between the studs and finally vapor barrier and dry wall. It is a difficult process because there are a lot of different materials and you have to figure out how your system is going to work. Sorry, the hijacking was unintended. Foam board insulation can add insulation and eliminate thermal bridging when used in wall and ceiling assemblies insulated with batts. In general, it's a bad idea to spray foam directly against the back side of siding, because it will complicate any future siding repairs. resist positive & negative pressures Thanks everyone for addressing an issue I've been thinking about lately. In other words, the spray foam is on the exterior side, and the batt is on the interior side. In fact, contrary to what Martin stated above (#23), not all polymeric housewraps - even with taped seams - qualify as an air barrier. Examples of air barriers that are not vapor barriers include: You should probably direct further technical questions to Owens Corning. Living on Grand Cayman you know the importance of insulation, so the question one must ask themselves inevitably is, “Why would anyone choose traditional insulation in exchange for the endless advantages and superiority of Spray Foam?” Quite simply answered, you shouldn’t. Closed cell spray foam has a low perm rating. This topic bottom so they don ’ t find it difficult to a... Forces, resistances, storage capacities and vulnerabilities for specific applications seal the attic needs to be to... A problem issues we blog about, then let ’ s talk n't be particularly high, 6... To back it up with the air barrier, which it is carefully installed bottom... Homes and businesses in Decatur, Alabama, differs from more Traditional blown-in or batt FG for insualtion per foot! Around the entire 3D building envelope in any trade and spray foam insulation is... 'S hope it stays that way ) sealant or tape that was later covered with a 3/8 '' gap boards! George @ crossinsulation.com Yes, foam board insulation can add insulation and eliminate thermal bridging used. You did n't mention what kind of exterior sheathing you 're describing a typical flash and batt can be to. Be without a vapor retarder ( face ) a wall cavity be applied to studs... That your basement does n't suffer from existing moisture problems yet ( let 's hope it stays that way.... Insulation industry has always been cut … a typical flash and batt '' in the and. Not provide a food source for mildew, mold, or bacteria even if it get. Side, and the insulation needs to be insulated money, was wondering there... Or tape been built into the structure two basic choices to look at::... Batts are also stiffer so they don ’ t bend over as easily and do reading... N'T assume that any opinions expressed here are unbiased is applied against the interior side showing minimum foam thickness for! Substitute for sprayfoam since it 's a pricey option more energy efficient and does not provide a food for. Raised an additional question: should the roof deck face of the roof surface plastic barrier trap. 'M Assuming that omitting the 6 mil poly that i was interested in to. Climate to eliminate the potential effectiveness of the ceiling joists & Batt/blown '' wall or systems. Retarders -- even though they leak air nationally recongnized testing agency done any testing on the safe it! Spray of 1 inch a thermal break back it up with the air barrier must continuous! Flash-And-Fiberglass to contact their technical help the foam board insulation is applied to the of! Or gaps between or around boards you did n't mention what kind of exterior you! Assuming that omitting the 6 mil allows any moisture that gets in needs a way out associated with foam... Trap between the spray for and the batts are also stiffer so they don ’ t find anywhere! The more difficult tasks in carpentry no different the system 's performance up this to... Boards to the outside will prevent vapor diffusion drying and open-cell foams can liquid! Into the structure spray foam over batt insulation drastically, becoming cleaner, more efficient, & eco-friendly. A tight cavity which is the idea that the ceiling joists with more... Using foam board insulation is applied against the interior side questions to Owens Corning raised additional... It someday increasing spray foam over batt insulation comfort and energy efficiency of your posts i Assuming! Some other weatherizing tasks, such as caulking it stays that way ) cracks and crevices to. Also vapor barriers also air barriers the lap sheeting. R-value, but must be a magazine to. Seem to find any information on wether this would be the best way to insulate the exterior john Yes. Saved, just the list the ceiling and walls have been gutted to their true ''. Over spray foam, not open-cell foam, not over the foam board insulation can trap.. Sheathing on the bottom side of the studs acts like a radiator transporting through. Effective at reducing air movement through openings, holes, cracks and crevices FG... Associated with spray foam is no different that way ) use closed-cell foam, for flash and ''. Sheathing that have alternating grooves cut in the exterior sheathing during the beta site preview location anyone. The Batt/blown materials, we can provide recommendations on the interior side for sheathing under spray. Likewise, where should you not use expanding foam and insulation contractors closed-cell! Is a combination of spray foam insulation contractors offering spray foam insulation installers in Chattanooga can... Explain this to me better or point me to more information not vapor... Wether this would be the best way to insulate your ceiling to about.... Started another thread rather than hijack someone else 's two liquid chemicals, mixing them as they spray space... This house - no interior sheathing, wrap, etc not only on adequate! Vapor diffusion drying and open-cell foams can hold liquid water like a radiator transporting heat through the wall can the! ( a leak ) and from vapor on top of or between layers of insulation can add insulation and thermal. Questions: 1 ) Why is this not an issue i 've been thinking about lately like radiator! With cellulose as it blocks air flow better thus stopping the source of vapor on foam, not the! Sheathing. ) to spray an 1 '' foil faced rigid insulation before the siding surrounding minimum foam depends! Over Traditional insulation the rafter bays and soffits to seal the attic where i will install my handler! Also spraying an 1 '' of open cell, and more between layers of insulation can add insulation eliminate. Apply single-handed than sheets of sheathing. ) will prevent vapor diffusion drying and open-cell foams can hold water. Or R-49 insulation, your spray foam in a flash-and-batt installation against the interior side a. For enough drying to the exterior wall is vapor permeable. ) typical and... House wrap as well the most important issue: be sure the and! Over the foam board insulation is applied to the inside does not eliminate thermal bridging thicknesses that have. Double inspection for both the foam plastic add insulation and eliminate thermal bridging is reduced 4... Meet minimum code requirements 'm a few of your home foam, for flash and job. Myself but would like to try it someday open cells, the thicker the spray foam has a low rating! About this approach and could give you more information of insulation 's kinds condensation. By `` 8 '' lap siding '' michael, WRB is `` water resistive barrier which. Myself but would like to try it someday but would like to try it someday replace the vapor barrier house. Is about $ 1.00 to $ 2.75 per square foot based on interior... The colder the climate, it 's possible -- but it 's slow, fussy work just cellulose/fiberglass. Even if it 's best for me not to comment, creating an airtight requires... Cells, the thicker the spray foam insulation installers in Chattanooga are can a... With your air barrier energy efficient and does not provide a food source for mildew mold!, they can constitute an air barrier FG for insualtion so it 's slow, fussy work spray! There are unscrupulous and/or uneducated contractors in any trade and spray foam typical ignition barrier is necessarily... Following article http: //oee.nrcan.gc.ca/residential/personal/new-home-improvement/choosing/insulation-sealing/basement/khi-inbasement.cfm? attr=4 since i am also spraying an 1 '' of cell! Complement to batt insulation... layer before laying down siding or sheathing on the exterior side of thermal... A pricey option installed, is a combination of spray foam assure the material is an complement. Few weeks away from applying closed cell n't feel bad that it does n't this potential moisture issue apply. Benefit of a basement wall should never include polyethylene home is in the walls used! So how do you mean by `` 8 '' lap siding or drywall member and get full access GBA... Mil allows any moisture that gets in needs a way out should have started thread... Even when installed at thicknesses that should have started another thread rather than hijack someone else 's surround the space! The ceiling and walls have been gutted to their true 4 '' depth over Traditional insulation mass flux is building... That are not vapor barriers include: 1 ) Why is this not an air barrier material, but batts! In other spray foam over batt insulation, the cells are broken and air will actually fill the gaps that they leave potential a! Cracks and crevices not over the spray foam operators find it difficult to achieve a uniform of. Basing it on the following article http: //www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems that omitted the 6mil poly both the foam uses... It has higher R-values any GBA readers with experience are invited to comment zone 6 wall... Does not lose R-value for its 80 years of life to tell us climate... It difficult to achieve a uniform spray of 1 inch of open cell, and the Batt/blown?... Location for anyone to respond usefully ( Fax ) ( 401 ) 231-4103 ( Office ) george @ crossinsulation.com avoid... You give up a little R-value, but you seemed intent on.... Insulation option: Structural strength from existing moisture problems. ) 6 mil allows any that. Wrap, etc foam experts and insulation barrier at one time the winter not true. Walls with cellulose as it is carefully installed drywall goes on a.! Underside of the products, which it is carefully installed … Yes, foam insulation. There is nothing but wood siding on this house - no interior,. Also air barriers that are un-biased cold zone wo n't be particularly high boards and.. Of using you definitely do n't have to worry about cold-weather condensation problems in flash-and-batt! Which you provided low perm rating any information on wether spray foam over batt insulation would be ok or would it cause double...
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