© 2021 The Taunton Press, Inc. All rights reserved. Acetone-based nail polish remover will also work to remove uncured foam. To calculate the whole-wall R-value of a wall, we…. I can't say I disagree with that. Spray foam insulation comes in different forms, like in spray guns which can fill in gaps and crevices, that can be applied inside your walls. Our process to retrofit existing walls is quick, simple, and typically takes just one day. How much rigid foam ends up in the dumpster? Cedar shingles We have a 1.5 story house with a 14:12 pitch vented roof structure and about R-19 roof insulation in 2x8 rafters. FAQ: Why Do Some Builders Avoid Foam Insulation. Spray Foam Insulation. “We use both open and closed cell foams, but we recommend open cell for homes because it creates an air seal,” said Skelton. I recommend running from any company that preaches only the virtues of closed cell foam. Its amazing to me how the residential building industry has never developed some mandatory education requirement minimums like many other professions, not that it would solve all issues, but at least elevate the base knowledge and performance. Foam insulation creates an air seal with a minimum of 3-inches of open cell or 2-inches of closed cell. While foam insulation won’t eliminate the outdoor noise completely, it will greatly reduce it. Stephen Bonfiglioli recommends the use of 1-inch thick strips of EPS between the stud and the drywall. Again, I very much enjoyed this article. People say closed cell adds structural support, but honestly, your drywall is just as strong or stronger as the foam. One minor critique In US zones 5 & lower it doesn't even need the low vapor retardency of the interior side wood sheathing to meet code, only for structure. Unfortunately, these products don't have any effect on cured foam. Each unfilled cavity is a pocket of air that drags down the energy efficiency of a home. After an hour, take off the glove and wash with warm water and soap, according to Air Seal Insulators Inc. Charlie Controlling the Dew Point With the Class-II vapor retardency of the OSB/plywood, the R-value of the fiberboard while a welcome thermal break on the framing, it doesn't need to be thick enough for dew point control. While it’s true that closed cell spray foam insulation is a durable material, it’s not that durable. But a WUFI simulation of that wall in a US zone 7 location would likely show that it still works. This establishes the base tax amount for the structure portion and then they add for fireplaces and other bits. The thermal bridging through your 2x6 wall studs tends to undermine any advantage from using spray foam between the studs -- as noted in the article above -- so I would recommend cellulose. “This leads to a sizeable amount of heat and central air loss.”. “It’s been scientifically proven that the temp of the shingles rises only a couple of degrees when there is an unvented attic compared to a vented attic,” said Garry Barlow, project manager at RetroFoam of Michigan. One thing to keep in mind is that the location of your ductwork, pipes, appliances, and the general construction of your home will also impact sound. RELATED: What is Closed Cell Spray Foam Insulation? With open-cell spray foam, the interior moisture can easily diffuse to the cold wall sheathing. Roofs are complicated. Response to Nicolaas Wilkens Can I Be Inside My Home During the Foam Insulation Installation? Your initial plan does. If the Zip R sheathing was properly fastened, according to the nailing schedule provided by Huber (the manufacturer of Zip), your wall doesn't need any more "stiffness." It has knee-walls, the floor joists are open at the rafter-joist-wall intersection and we have a mini-attic insulated to ~ R-30. When installed properly in adequate conditions, the foam insulation we use does not shrink. Others I've spoken to have said not to use spray foam with hundred year old rubble walls since they're leaky by design and blocking the passage of moisture into the basement could cause problems … traditionally here they have used the framing dimensions from the plans and ignored siding, trim etc. Foam insulation creates an air seal with a minimum of 3-inches of open cell or 2-inches of closed cell.“With traditional insulation like fiberglass or cellulose there will be a lot of airflow through these materials,” said Jacob Stacy, customer concierge and project manager at RetroFoam of Michigan. © 2021 RetroFoam of Michigan Inc. All Rights Reserved. RetroFoam of Michigan has more than 17 years of experience insulating thousands of homes and pole barns across the lower peninsula and the greater Toledo area. That said, the conclusions reached in my article are not seriously affected by these points. I understand that requirement may be under threat in the legislature, but for now, good things are happening. Learn to get foam insulation off your door and other surfaces. Even OPEN cell foam isn't the greenest or most sustainable solution. It would also exceed building code and have higher over all R-value. “If you are needing your insulation to add structural integrity to your home, you have bigger design problems than insulation,” said Mark Massey, owner of RetroFoam of Michigan. Installing closed cell foam with an exterior foam insulation in walls or installing closed cell foam with most roofing underlayments create a moisture sandwich that rots wood. Where possible it's nicer to the planet to use ultra-low impact cellulose rather than open cell foam, if not cellulose, rock wool, and use caulks & tapes for air sealing. Bottom line: If you're going to use closed cell foam, using only the minimum amount needed for dew point control and using lower impact fiber (or open cell foam) for the rest is going to be nicer to the planet and usually quite a bit less expensive too. In the past, open cell spray foam had a reputation of retaining water like a sponge, luckily that isn’t the case now. This insulation material is popular for its high R-value and good air-sealing and vapor-blocking properties, but cost, health, and environmental concerns cause some builders to have second thoughts. The thermal bridging performace hit isn't quite as large as with walls, but it's still real enough. Thank you Martin for the excellent article (and to Dana who I think has been hammering this point in for as long as I've been a member). Poorly applied or mixed foam insulation can have issues when installed, which has led to this misconception. For more information on this concept, see "Calculating the Minimum Thickness of Rigid Foam Sheathing." Christopher, - Michael Schrauben, Clearing Up Misconceptions about Spray Foam Insulation. Throughout her career as a journalist, she has won several awards from the The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. These foam insulations don’t promote the spreading of fire and will actually extinguish once the flame is removed. Icynene open cell foam installed in attic assemblies is not risky. spray foam insulation | Saw straight through the foam to remove the excess. If you install 1 inch of XPS (R-5) on the exterior of the sheathing on your 2x4 wall in Climate Zone 6, the rigid foam won't have a high enough R-value to prevent moisture accumulation in the sheathing during the winter. Misconception: Closed Cell Spray Foam Adds Structural Support to the Home, What is Closed Cell Spray Foam Insulation? Misconception: Electrical Work and New Wires Can’t Be Run with Foam Insulation in the Walls. You're right that spraying open-cell spray foam on the underside of roof sheathing can be risky. Keep slicing the foam off in small pieces until it’s completely flush with the rest of the wall. Nebraska, because of the low number of taxpayers hits the property tax very hard. RELATED: How to Insulate a House Without Taking Down Drywall. RELATED: How Thick Does Spray Foam Insulation Need to Be? I wonder how they measure square footages for houses with exterior insulation? In towns that use the area of the foundation as a guide, it may reduce your taxes to switch from double-stud walls to Larsen trusses (since Larsen trusses overhang the foundation). Open-cell spray foam isn’t as dense, so it’s easy to trim. The biggest doubts I have personally are related to cost and ability to find someone able and willing to do the work. Believe it's zone 5 so costly framing to increase R value may not pay off but taping the studs seems reasonable and relatively cheap. It definitely helps clarify the impact of the un-insulated portion of the studs. Misconception: Foam Insulation Shrinks Over Time, Misconception: Spray Foam Can’t be Installed in the Winter Months. The 3" of 2lb foam is 1lb of polymer per square foot of cavity area, whereas 3.5" of half-pound foam is only 0.146 lbs per square foot- call it 0.017lbs to account for any excess that's trimmed & discarded. RELATED: Does RetroFoam of Michigan Install Foam Insulation in All Weather Conditions? TJI/framing factor “I once had a homeowner tell me she was told by another foam insulation company that she couldn’t return home for 24 hours,” Barlow said. “Foam insulation doesn’t soundproof, but it can dampen sound up to 80 percent,” said Joe Skelton, project manager at RetroFoam of Michigan. RELATED: What is the R-Value of Spray Foam Insulation? Open cell foam insulation is a pliable material, which means it is easy to work with if you need to do any rewiring in the future. This approach has been successful in a number of temperate and cool climate European high-performance houses, including this UK Level 6 standard house in Norwich, Norfolk England: http://www.walesonline.co.uk/whats-on/whats-on-news/gallery/grand-designs-norfolk-eco-home-7903432. As a matter of fact, it can be done from the outside and the process only varies depending on the type of siding your home has. Misconception: Open Cell Spray Foam Absorbs Water Like a Sponge, There are some open cell foam products on the market that do, One of the benefits of open cell is that is doesn’t retain water and doesn’t promote, What is Open Cell Spray Foam Insulation? (Get the heavy duty blades for more dense material) These work great on spray foam, board type insulation, soft foam (for tool/pelican cases) etc. 11 7/8" TJI's with the specs you note in a 16" o.c. I'm not really advocating ANY closed cell foam (response to #8) This keeps it from deteriorating or falling. We are working on a project in Climate Zone 6 and have specified rigid exterior insulation (2" XPS) over 2x4 framing with fiberglass batts or cellulose wall insulation in stud cavities. The next step is to apply petroleum jelly to the area, cover it with a glove, and let the jelly soak in. Some of the insulation details can be observed in the Grand Designs television episode, which is available on Netflix, if you're interested: (I think it's the 2nd season, 6th episode in the Netflix listings- could be rong, offen am...). That's 700% (7x) as much polymer, for a paltry net performance gain on the order of 10%. :-) ) “It’s something we are trained to do all year long.”. Sometimes I have to remind myself of this. The R value of fiberglass batting is 2.8-3.9; spray foam’s R value is 5.5-7.12. Spray foam insulation dries into a hard foam with a solid, shiny coating that makes it nearly impossible for water to absorb into foam, mold to grow, and moist air to pass through it. I wasn't trying to debate that flash-and-batt is superior in general. This is part of why I personally like the idea of flash-and-batt more. (I can also tell you … construction details. They almost always go by appraised value, with the size of the dwelling being one factor. Closed cell is best against concrete block in encapsulated crawlspaces and metal buildings. Get building science and energy efficiency advice, plus special offers, in your inbox. I thought readers here might appreciate knowing I was just discussing this very concept last night with the Energy Auditing class I teach at the local community college. Walls: Nicolaas, The Most Frequently Asked Questions and Answers About Spray Foam Insulation for Pole Barns, Spray Foam Insulation for New Build Homes: Answers to Frequently Asked Questions, Answers to the Most Frequently Asked Questions About Foam Insulation for Existing Homes. Also, if there are obstructions or windows, we’d have to go below and inject into the cavity anyways.”, RELATED: RetroFoam Injection Foam Insulation for Existing Walls. “You can push a wire or fish a wire through open cell foam,” said Weaver. “Foam insulation will make it a little better, but not completely fix it,” Weaver said. With a professional, you can be assured of thorough, high-quality work and reduced risk of wall damage. It can be sprayed into an open cavity, like in new construction, crawl spaces, attics and rim … Closed cell in our area is normally installed at about 2" of depth in walls and 3" in attics. Not all open cell foams are created the same. Print; Wall cavities are more than space. “Fiberglass and cellulose end up costing you more just in the cost of reinsulating and wasted energy.”, RELATED: The Total Lifetime Cost of Foam Insulation: It’s Less Than You Think. There is so much thermal bridging in the walls and attics that it doesn't work very well. Clearing up these misconceptions about foam insulation probably has you curious about the benefits of foam for your project. Finally, to remove the last traces of spray foam insulation, apply lacquer thinner to the foam and wipe away with a rag once the foam has loosened … In a cool/cold climate a wood framed house with cellulose cavity fill, the structural sheathing can be OSB or plywood on the interior side of the framing, and 2" / 50mm fiberboard (~R5-R5.3) on the exterior under rainscreened siding. RELATED: Open Cell vs Closed Cell Foam Insulation: Which is Better for My Home? Most flashers in our area spray about 1/4" of an inch or less and then cram the batt in. But from a cost point of view it's sometimes cheaper/quicker (time=money) to use open cell foam than blown/sprayed fiber, and it's the least-terrible foam option out there (including rigid foam). Christopher, It’s important to know exactly what your contractor is spraying in your home and that they are an experienced foam insulation contractor. Response to Steve Kreisher You're also right that the shape and conductivity of a rafter affects the thermal bridging penalty. 2 Cut down and into the foam -- perpendicular to joists or studs -- with smooth, even strokes. Response to Charlie and Malcolm (Comments #9 and #10) What it’s Made of, How it Works, & More, Misconception: Closed Cell is Best for the Attic Roof Deck or Floor. High-R properly vented cathedralized ceilings are cheaper and more resilient, if it's new construction with reasonably simple roof lines. Flash and batt in my opinion is the choice of unprofessional installers. Climate Zone 6 Wall System My next-door neighbor had trouble finding anyone comfortable working with Roxul ComfortBoard when he built last year. One nit to pick is that the cellulose was blown in ~4" holes (on the interior OSB side) with a large hose, not with dense-packing hoses, and thus probably not at a density sufficient to eliminate settling over time. Minnesota is the same - based on exterior measurements. It is intended to provide general information to professional persons who may be involved in installing spray polyurethane foam. We'll see what I actually end up building with. Misconception (noun) – An erroneous conception; mistaken notion. “That’s why it’s crucial for you to know exactly what’s being used for your project,” said Eric Garcia, general manager at RetroFoam of Michigan. You must be a magazine subscriber to access this feature. I've heard of a few owners of energy-efficient homes who managed to convince the local assessor not to include the entire area of a thick wall. “We have no issues installing spray foam during the winter months,” said Ashley Bedtelyon, office manager at RetroFoam of Michigan. With open-cell spray foam, the sides of the studs (above) are not as exposed as they are in a wall insulated with closed-cell spray foam (below), and this fact reduces the thermal bridging penalty. We are affordable green builders and stopped using open cell foam as cavity insulation the day we finished our very first home with the product. In a new build home, an HVAC contractor will determine the size of the system your home needs, which in turn can keep your home from being too tight. Installers of open-cell spray foam will fill a 3.5-inch-deep cavity completely, allowing the foam to expand until it is proud of the studs. 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