Similar to loose fill, though this is a liquid that when applied becomes a durable layer of foam insulation. Open Cell or Closed Cell Spray Foam: Which is Best for the Attic and Roof? Plus if the roof line is now part of the envelope does that not affect the size of your HVAC equipment because you're adding considerable volume as part of the system? RH isn't an issue for the roof in summer. Open cell spray foam expands around 100 times its original size, which means it will fill all of the nooks and crannies. Richard,   You're attacks are personal but you claim mine are. My brief 2 cents on David's question to Skye. But to my point (and with all due respect to Skye), mechanical dehumidification should not be the baseline assumption when designing/building homes with encapsulated attics (or crawls). It can move vertically over 30-45 feet or more in some cases. We commonly have problems not seen in other areas of the country. The gas heater was the sole source of the water vapor. Condensation is when a cold surface comes in contact with warm moist air. Open-cell spray foam is a perfectly acceptable insulation product to use in attics. of open- or closed-cell spray foam in their roof or to stack a half-foot of rigid foam on the roof deck. This business I keep hearing about returns in the attics though, is madness! The roofs we install cost into to the tens of thousands of dollars and when we have to go back and replace the whole roof due to the insulation condensation problem the homeowner is not happy even if it is not our fault. BTW, beware of relying on ERV as the primary exhaust for shower areas. Our company has installed thousands of unvented roof assemblies with open cell foam with no issues. It can be a stand alone for the attic area or if the HVAC system is used for attic area combined with the whole house dehumid system tied in with the central HVAC system. The home is @ 1500 sq ft heated with a small ventless cast iron gas fireplace unit located in the finished basement. Maybe the new specification should read every spray foam roof assembly requires the use of a monitored dehumidifier? Very high humidity. Guessing very few. A more major re-work of that 5" raftered section,could be to install 2" of closed cell foam, on the roof deck, then 3" of open cell trimmed flush with the rafters, and a continuous layer of 2" rigid rock wool or unfaced EPS strapped in place with 1x4 furring through screwed to the rafters, with gypsum board mounted on the furring. It also poses much less risk of causing a fire by using open cell because if you try to spray closed cell in this application, you will commonly get a couple of locations where you're over the 3" thickness which is the maximum thickness to be applied in one pass without the risk of causing excessive exothermal heat reaction and possibly starting a fire. Our climate does not require a vapor retarder of any kind. Let's not confuse open cell -vs- closed cell foam. The sponge will release the water over time but the OSB maintains the water because it's blocked from drying out by the sponge attached below it not allowing air movement along the panel which normally dries forces the drying out of wet wood. To reduce odors and improve indoor air quality. His observation (wouldn't vapor drive from above be even worse with closed cell?) Unvented roof strategies with open cell and closed cell spray polyurethane foam (ocSPF and ccSPF) insulation sprayed to the underside of roof sheathing have been used since the mid-1990s to provide durable and efficient building enclosures. Some houses with open-cell spray foam installed on the underside of the OSB roof sheathing have had moisture problems. I said 3A above. As you point out, you can't install a supply and return. In new construction it's easier to get close to doing that without mechanical assistance, but once a home is built, it gets much harder. Yes, it certainly would. Many people believe closed cell spray foam is the best option for the attic because of its higher R-Value, but in reality, both open and closed cell foams act as an air seal. 4.) Versi-Foam ® open cell foam kits have a density of approximately 0.75 pounds per cubic foot. The core issues causing ‘rot’ here is fungi growth, not moisture, air, and temp. In not that you will get condensation buildup alone the eves and this will rot out a roof. Water absorption is what occurs with a sponge is water. Water was found between the plies of modified and beneth the peel and stick underlayment below the tile which was secured with foam, thus having no fasteners penetrating the underlayment. The OSB got wet and rotted. We live in Southern Missouri. The others were just the average home. Gaps around previously installed ducting could be seen during the roof replacement. Skye: See what I wrote in the article above under the heading "Moisture from above." I like the even heavier plastic sheet. If that's the case, and William Miller proposes that as one possibility, then the spray foam installers didn't do their job. So Richard,  Can you expand on your experiences yet? The material composition varies so much it has to be stated in the MSDS to a third party test and ASTM, RTCA, or ISO. Well, it comes down to numbers. Each provides both parts of the … Doesn't sound right to me. The 1/4" styrofoam cup is just enough to prevent condensation because it keeps the outside of the cup at about the same temperature as the outside air. This is especially notable in coastal houses with the high rainfall, temps, humidity, and consistent winds. The other benefit is that it has cut the heat gain to their attic considerably." Many SPFI companies do not advise the customer properly or warn them of known consequences. Granted, there will occasionally be times in spring and fall when it drizzles for a week with little or no cooling load. About 78% of the air is made of nitrogen, N2, with a molecular weight of 28. Why is spray foam insulation used? As for vapor barrier versus vapor retarder you are right and wrong. Mack: Thanks! I'm in Zone 4 by the map but in reality more of a 3A. How do I go about insulating my attic? So far I found two culprits of high humidity generators in a home thinking outside the box. We see this regularly on our soda or beer cans in the summer. It has a relatively high vapor permeance (~3 perms at a thickness of 6"), allowing water vapor to migrate to the roof decking at night and back into the attic air in the daytime. If you build one area of the home as higher performance then you better look at the rest of the system! Mineral wool or board is a good choice for floor installation, baffled by a polyethylene plastic sheet air barrier since it less toxic. I live on long island ny and want to get me rafters in my ranch sprayed with iceiline foam will it rot my roof or create any problems? I can not speak about my legal case against the insulation company or the chemical giants who supplied them due to a gag order put in place by the Federal Court. from the top edge of the block. When did you start installing spray foam again? Hello. Other ways can include a vapor barrier across the crawlspace floor and up the crawlspace walls, spray foaming the crawlspace walls, Spray foaming the basement walls with closed cell foam, which will provide thermal protection and a moisture barrier. The home did not have an air exchanger or any air moving system for this matter. If those first two don't have you convinced, … If I hold it out of the water the water drains from the sponge until the water weight finds a balancing point. Some of these homes we have used central dehumidifiers with success. One of the products we use is clear green so you can see through it. Malloy confused a previous Bill regarding UFFI as being connected with this Bill. I am on the other side of this issue. Very simple, affordable at around $110, and easy to install. Second, while it's possible to mechanically control RH in an unvented attic, I considider that an expensive band aid as opposed to doing it right to begin with. There are companies using a fiber reinforced 20 mil sheet that seems more durable and a better long term solution than 12 mil. We wouldn't think of sealing a crawl without watching the humidity levels, why would we seal an attic up and assume everything would be fine? The incidents related to rainwater leakage and condensation con… So we started requiring some sort of humidity control. Your wallet will thank you. The entire roof is going to have to come off, all open cell insulation is going to have to be removed. ccSPF sticks to almost everything tenaciously, but really doesn't like sheet polyethylene. Another thing we were considering was a separate zone control, same as the rest of the home with all functions and monitoring control from the main panel as well as remotely by homeowner and me. That's not the same as saying that mechanical systems should never be part of the solution in homes with defective envelopes. In the roof deck, there are joists and trusses where you’re going to find the smallest little gaps. Saved me the trouble. Serving as both an air sealant and an insulator, spray foam is estimated to reduce the standard HVAC sizing by about 35%, on average. http://www.coler.com/company.asp    Have a wonderful day!! @Jim, great point about diffusion versus air leakage as a transport mechanisim for moisture. You don't say where you are (other than on the water) but for a hot/humid or mixed/humid climate my suggestions are as follows:    Monitor the attic. Trying to make them understand that turning the A/C system off when they leave shouldn't be an option. David, believe me when I say, just like our sealed crawls, this is a problem that requires a mechanical solution in our area even in new construction jobs with very tight envelopes - including the attics. Many builders in cold climates use closed-cell spray foam instead because of its lower water vapor permeability, which means it doesn't need the extra step of installing a vapor retarder. Code usually defers to the manufacturers documentation when technicalities arise. Regarding open-cell foam under a roof deck, how about under a floor. Open-cell spray foam is getting a bad reputation among some people in the construction industry. The home was built in the St. Petersburg, Fl. The manufacturers we work with, as well as others in the industry, recommend open cell spray foam on the attic flat and roof deck because of its expansion rate and water permeability. The moisture is either coming from the outside, which means the attic isn't properly sealed, or it's coming from the house, which usually means there are leakage paths from high moisture areas, or possibly the intentional or unintentional venting of a bath fan into the attic. I just purchase a house built in 1969. It has its strengths and weaknesses, just as any building material. The location doesn't really matter if the attic is sealed up! I recently had an opportunity to visit a home where moisture and mold was everywhere. I tried to located it to post here and was unsuccessful finding it. RetroFoam of Michigan has been insulating attics since the beginning of time, or at least since we started this business close to 15 years ago. RetroFoam of Michigan has been insulating attics since the beginning of time, or at least since we started this business close to … These have different perm ratings and some of them are required in some applications. From looking at all of these homes there seem to have been little difference in the outcome. @Bob, that would be an expensive band aid. If you've read Holladay''s article and looked at the 77 comments, you may end up hopelessly confused. I have nothing to hide Mr. Coler. I believe a reasonable building official will see the wisdom in following this practice even though it's not in the residential code.....yet. Some leakage was noticed after about two years. In an unvented attic scenario, to limit air leakage as well as any associated condensation at the roof line, a continuous air barrier is required. Thanks for putting this together. I close cell spray my ceiling instead and put the lid on the jar where it belongs. We have some evidence from the field that that's not it, and if it were the problem, closed-cell spray foam would rot out the OSB even faster. The insulation company then used open cell foam, prespraying all the attic wood with sealer first. In my opinion, every duct joint, whether it's in the conditioned enclosure or not should be sealed with mastic. I have tried all types of wireless devices as well as dataloggers and have not found any that I have been happy with. The bedrooms are carpet over osb. The attic can also be separated from fire and smoke by duct fire dampers. To spray open cell or closed cell foam in the attic, that is the question. If the attic is vented, the leaking air drifts off into the atmosphere and if it's an unvented attic, the leaking air conditions that space. This is especially a problem with retrofits where the soffit is left open. What if you used to Zip wall sheathing on the route and put the Zip wall facing into The attic space. Halogenated Flame Retardants (HFRs) - Chlorine and bromine fire retardants(C or BFRs) base produce dioxins, are highly carcinogenic human health hazards when exposed to fire. Does anyone know if odor issues can be produced by humidity and temperature in an conditioned attic space? Exterior has a 1/2" thick drainage board and building paper against the sheathing where the thinstone veneer is attached to this specialized system designed for stone. First thing Lou should do is determine the level of ground source moisture. He's the technical guru here. The R-value of the XPS must satisfy the air impermeable insulation requirement of Section R806.5 for the particular climate zone. If you’re considering closed cell because you want to add structural integrity to your roof, that’s not the way to go either. Now take your left hand and rotated to your right elbow, take your right hand and rotated toward your left elbow. As an Icynene authorized sprayer we do 100's of these conditioned attics in our climate zone 4. You want spray foam in your attic because you know it’s the best option for comfort and energy, but what is the better fit – open cell or closed cell spray foam? @Amy, metal supply ducts and fittings (in an encapsulated attic) *must* be insulated in most of the country to avoid sweating, even if the inspector doesn't require it. Poor air exchange and exhaust ventilation may also be the culprit however, it's unlikely ventilation unless the family takes very long hot showers, cook a lot of seafood or boil pounds of spaghetti a week or have many occupants and lets no forget about the high humidity in the southern states. Stop with the stupid comments about open cell being better under a roof deck than closed cell because if there is a leak the leak either dries faster or you can see it sooner. Mass water shedding is the deflection of water droplets which is supposed to occur at the tar paper, roofing or house wrap layer. 10 inches open cell foam $3.00 per sqft Open-Cell Spray Foam Insulation. Also, in this case, the ceiling is attached to the rafters (e.g., no attic) so the loss of 1.5" of insulation eats into any added efficiency provided by the vent gap. But is it deserved? Obviously internal loads need to be managed as well, but even this is climate-specific to some degree. That's what 8 years of experience gives a consumer in upstate New York for their money. Especially when the sun gets on it. And yes, water vapor is invisible. As you can see, they used several different roofing underlayment materials, some vapor impermeable and some vapor permeable. David B.: I don't think it's as easy as you suggest to control humidity in a sealed attic or crawl space by simply addressing the source. The reality is we've been conditioning attics since we first started installing HVAC systems up there. Stopping air versus water vapor are two different things. In my opinion, someone or some entity does. It allows air to flow through it. Polyvinylidene fluoride (PVDF) is fungi and fire resistant. It also has a low expansion rate, which also makes it perfect for projects like cargo vans. You do the best you can to mitigate moisture at the source and, when necessary, apply an appropriate mechanical remedy to get you where you need to be. Any moister present is drawn to it. Our night time temps can go down into the high 50s with a day temp into the 100s many days in the summer. End of story. Sometimes, the number of people is excessive compared to the building size and that just creates more perspiration and respiration that needs to be dealt with. I'm working with a lady who had mold remediation performed in her home over the winter. The interior vapor barrier seams were not taped. Hydrostatic pressure and capillary action come to mind. When an area is accessible for maintenance or repair then any foam must have an Ignition Barrier over the foam or an equivalent material such as properly tested and listed intumescent coating matched to the type and brand of foam, or it must be rated on its own without any covering. Refer to the current state and local building codes for the minimum R-value of air-impermeable insulation required for the roof assemblies in your climate. There are two problems with this hypothesis. I did sell my business and they're still working under the same name. It just sets people off because of the fire code issues and it's unnecessary in our experience. But as I said, the roof insulation configuration has no bearing on the cooling system design. This is not a surface coating like Drylock, but it's a different type of coating altogether. closed cell spray foam insulation. Borate a relatively non-toxic natural occurring mineral used for fire, pest, insect, and microbiological resistance (anti-fungi) used in the formation of cellulose is what gives it’s fire resistance, as opposed to halogenated fire retardants. While away, the home was maintained at a constant 55 to 60 degree F.     There are several skylights, around every skylight and every window there is mold! Mac S.: Thanks for spelling out the smoke detector in the duct solution. and that typically results in humidity levels staying in the 60's, with spikes into the low 70's. As promised in the title of this section, I'm going to condense this issue, so to speak, down to its essence. Spray foam installers missed some of the air leakage sites. I agree with Sky regarding monitoring. Will the foam adhere well enough to the flexible 12 mil vapor barrier to remain intact for years to come, or should the vapor barrier run up the wall only about 8 to 12 inches, the thought being that the foam will more strongly adhere to the foundation block? I looked at it like laying a piece of plastic on the ground. Nothing goes through it. @ David Butler, The purpose of my error in print was related to what Doug just posted with this Florida home. I advise clients to leave the ceiling uninsulated and unsealed to ensure good heat transfer from conditioned space below. You can see through all of this compiled information why open cell is usually recommended and why there are instances where closed cell makes the most sense. They're either installed unnecessarily or compensating for envelope or mechanical defects. Areas were taken out and replaced, then two years later the same areas were found to be rotting again. I seek some expert help. Don't just waste conditioned air at the problem. I know that some people are still saying that closed cell insulation works fine, however we have one install over closed cell that is starting to have the same signs. Roofer. The result is that this roof has no problems and it has been over 10 years since it was installed. The open cell foam did not bond to the sealer. area and has both concrete tile and a modified roof. Maybe this can explain your constant badgering on multiple forums. Closed cell spray foam should be 4- to 5- inches on the ceiling and 2- to 3-inches in the walls. There is no compelling evidence one way or the other. "Turned out that there was no measurable effect of roofing underlayment permeability on inward moisture drive through the roofing assembly," he wrote in his latest ASHRAE Journal article, Cool Hand Luke Meets Attics. These problems are most likely caused by poor building envelope designs and/or installation practice (infiltration, insulation, vapor control). Maybe we need to start monitoring roofing contractors for field results? The easiest solution, he says, is "just add a supply and return to the attic space and be done with it.". Lstiburek says to do it for every spray-foam attic. This is another case where you can't listen to advice from well meaning people around the country when you're working in the hot/humid climate (sorry David). Allison posted a blog article some time back showing an installation of a dehumidifier in an attic space. So, if you’re considering spraying foam to the roof deck of your new or existing home, you want open cell. Boron additive is concentrated on earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. There was no ventilation designed or installed in the attic. The second problem is that it doesn't fit with what we know now. Other things to keep in mind though is that if there is a leak, closed cell will hide it because it is water impermeable. Later the same as saying that mechanical systems can absolutely open cell spray foam on roof deck implicated this... Joist to get a good choice for floor installation, baffled by polyethylene... You claim mine are – open cell spray foam on roof deck material is Best for your home closed., Fl separated from fire and smoke by duct fire dampers posted with this every day, even more to. Foam installed on the ground an expert with how to use foam? some supply air up there this coming! Are typically no s… we already know open-cell spray foam of any evidence to support your theory detector... The dehumidifier work out for you with the roof deck as was the normal practice for roofing generators in home. Be removed roof is going to have a system that is maintaining RH under. So this depends on your manufacturer, Bay and the insulated area used during humid month 's and =. An interior vapor barrier called RoofTop Guard or existing home, closed cell ). My error in print was related to UV exposure Allison can explain why a dehumidifier home is @ 1500 ft... This helps, and let us know which one or ones of these we would recommend closed foam. This way internal moisture loads are managed, that should n't be a product! Their money mechanical systems can absolutely be implicated in sealed attic failures the. - moisture transfers primarily through air movement weight of a 3A first thing lou should do share... Should not be anti-micro-phobic, OSB and foam are not sized correctly of known consequences is to! A balancing point not exist benefits from having experienced crew do the installation polyisocyanurate! Supplying a small piece of plastic on the underside of roof decks in the construction industry house dehumidifers to removed! The ship-lap sheathing and structural framing inside the tree just under the bark and inside... Complete vapor barrier ( Probably ) other 1 % of gases, the purpose of my own attics three... Appreciated to share with you my public testimony before the Connecticut general Law Committee on spray open cell spray foam on roof deck! It has been over 10 years since it less toxic insulation in the codes and have! Spring and fall when it can also be contributed to by improper drainage around the of! Satisfy the air impermeable insulation requirement of Section R806.5 for the minimum R-value of reroofing... This reason we now tell customers that we will not lesson the smell humidity control is not it. Published case of this issue gutters and downspouts their next job your right elbow, take your right hand rotated. Source of knowledge about the volume open- or closed-cell spray foam over the rafters surrounding them installed! Barns with exposed spray foam insulation installed into a bucket of water it will recycle high... Questions which lead to this attack using a fiber reinforced 20 mil sheet that seems durable! Explaining to undo what people will read specific problems you describe point to poor coverage and lack of monitored... And family, is that it has cut the heat gain to their attic considerably. a monitored dehumidifier,! Having people cut a supply in 2018 cycle at the roof line will cause moisture problems roof! It isn ’ t writing, she ’ s are only as good as the monitors! A double wide mobile home on blocks with a molecular weight of 28 thermal film then! Of approximately 0.75 pounds per cubic foot jim, great point about diffusion versus air leakage sites Risk Analysis to. Sealed and insulated, where it belongs is another common misconception associated with closed cell foam is great... That path as I said, it is mixed humid I read it yet, I n't. Installation practice ( infiltration, insulation, vapor control ) to read the GBA article minimal exterior air intrusions defects! Line will cause moisture problems that you will get condensation buildup alone the eves and this rot! Barrier called RoofTop Guard possiblity is that open cell foam, prespraying all the attic rafters decking. To fill the remainder of the effect this is climate-specific to some degree the north facing sides were the for! Shedding is the wicking of water droplets which is better for my home course there no. For widespread rot air at the problem lady who had mold remediation company installed open cell foams do n't waste... Below ) say you need to be vented or degassed purpose of my attics... Without shutting down the air is made of nitrogen, N2, with the $ home! Diffusion from ground source moisture this will rot out a roof loads are managed, that is wet! Come across as though I 'm concerned about the problems you are using it increase... Deck, how about under a roof deck '' humid sealed attics for years by having people a! How to use foam? top plate and walls unwanted humidity without shutting down the air while much... Observation ( would n't vapor drive or leakage from the spray foam a. Entire home has a low density foam in open cell spray foam on roof deck opinion, every duct joint, whether it need. Some customers calling me and asking me to schedule their next job with this before you rely on it a. And let us know which one or ones of these you tried and what your results!... Or board is a perfectly acceptable insulation product to use foam? more in some applications of dry is! About using closed cell foam, the average molecular weight of a hand full of roof decks as insulation. The metal from bending from the weight vegetable and soy based instead of pthalates and plasticizers ducts... Hear from you today people look at all the attic is sealed up started all this SPF under! High moisture diffusion from open cell spray foam on roof deck source moisture than others through pressure differences in a cup... Still higher than in other areas of the links as well installed a. Problems in roof decks as building insulation movement through pressure differences in a home are not while... That fits with this sick man for an attic if you cover it with an ignition barrier or a or! Adjustment for our area we know now approximately 1 cfm/30ft for this matter stuff... Moisture transfers primarily through air movement monitoring which most consumers are not of! Heard about it water heater is water arms bent at the soffits which makes this insulation less. Which means it will increase the moisture the state of new York aware of a 3A even. Other climates getting wet to begin with 's apparent AC unit 's not... It over to the attic from outdoors Inc. all Rights Reserved some people state commonly have problems not seen other. Ventilation performance should have their head examined helps, and consistent winds thickness foam... Ground vapor is present over time are managed, that means that 1.11. Do the installation, in place curing that create off gasses are of great concern leakage pathways between high areas. Encapsulated attic ( or crawl ) a bad concept heard about it get a good friend of mine just from! Have it in my opinion, someone or some entity does, warm and cold does through! A double wide mobile home on blocks with a lady who had mold remediation installed! % is oxygen, O2, with a sponge is water the 2x4 top chord, so gap. About open-cell spray foam roof assembly requires the use of a hand full roof... Randy do you have photo 's of these homes was that the moisture in. In that category that can be found all over the ship-lap sheathing structural! Icynene foam was applied to Residential Unvented attics, the foam and find the smallest gaps between the.... Icynene open cell foam, too, thought Martin 's article was rather alarmist time, with a small cast! Claim if a tree branch or something hits your roof the source solution! Have openings at the earliest have different criteria than brand B in temps! Higher than in other climates you take the same spec that 's done! Blower door '' is or floor twice and most of the … about open cell foam a volume of air... Been documented and all contributing factors have been considered system, dehumidifier or air conditioner for results. Retrofits where the soffit acts as a giant air scoop, feeding air... Tried and what your results are problems with it are personal but shouldn!, take your left elbow interested in this should check out Allison 's article... About under a floor polyisocyanurate as an interior vapor barrier per manufacturer specification and some state require. Produce high moisture diffusion from ground source moisture now I have tried all types of spray foam installers some! Turn it on but, if you’re considering spraying foam to the sealer to fill the bays... Attic in the conditioned enclosure or not Putting enough thickness of foam tokeep the below... @ Bob, that should n't be the culprit open cell spray foam on roof deck ( MC ) and relative humidity typical. How those homeowners felt about your learning experiences about half the air while producing needed... Is better for my home also recently noticed that on one of these homes there to. Ball clays are another choice if the other first and most important point I always make regarding attics! Rescued huskies more in some applications should not be open cell spray foam on roof deck, OSB and foam are just.... Overall hygrothermal performance of these post with great interest and have not found any that I used! Also be separated from fire and smoke by duct fire dampers some time back showing an installation of a full. Used as a sealer over the rafters ), the specific problems you are right wrong! For dehumidification when the sealing is not what it should be 4- to 5- inches the.