“While I like the idea of eliminating thermal bridging through the studs,” Gregg writes in this Q&A post at GreenBuildingAdvisor, my concern is that there will be an air gap between the two layers of foam insulation (both of which have limited permeability). If you're installing a lot of it, consider wearing a disposable coverall (inexpensive at paint stores and home centers). Really, what doesn't it apply too. AND, unlike rigid sheet foam, which is fine within its design limits, I don't want to work with it period. Step 1 - … ;-). Why is "not-so-perfect" Good enough for a roof? There should be very little "leakage" in the field of the siding. Sheathing the roof with traditional sheathing materials, additional framing members stood off the roof to some predetermined thickness based on dew point calculations, a monolithic and seamless application of CC spray foam. Handling leaks Before insulating, coat the exterior of the walls with fluid-applied water-control and air-control layers. The housewrap is the WRB, but it's deep behind the foam. Thanks. simple. If the insulation to your bedroom is insufficient, you may even have trouble falling asleep because of all that noise. There are a tremendous amount of contradictions in this article. A very small percentage of siding goes on the wall with any back venting. When doing it from outside, the job involves removing some siding panels so that large holes can be bored through the sheathing at the top of wall stud cavities. Our latest shed is also a pavilion—and you can build it, too! You can insulate existing exterior walls either from inside or outside the house. It can easily pass though drywall without sign or trace, the smallest crack is a wide open door to water vapor. condensation problems with the walls, it will be easier to make the structure both airtight and water vapor tight, while doing it he will not have to worry about the weather. By the way the furring strips are rock solid attached on three sides by high density foam. It's important to have, no matter what weather conditions you live in, though the way you install it may vary. Cellulose Guy- "man our stuff is elastic and it moves with the house and it breathes but not to much and that closed cell stuff is just to expensive and to rigid and it doesn't breath and its toxic and don't buy all that crap about structural value and racking load man". No, I am not suggesting that the walls be built to leak. Press the poly into the sealant. Several local contractors have recommended the addition of between 3/4 in. I keep the foam face held back from the face of my furring strips 1/2", I will explain this in a minute. Would it not apply to the rain water management details, or the framing details, or the materials takeoff- of course it does. of spray polyurethane foam insulation into the stud bays. It evaporates. I had read about a potential installation using 4" stand off blocking/backing installed with a clip similar to a commercial curtain wall but that is even more off topic and would just be interested in some firsthand knowledge of Roxul since I don't think petroleum based products like foam, polyurethane and plastics are a long term sustainable solution for building materials. I don't want to try to cut it- seam it- fit it - caulk it-tape it- and worry about it. It evaporates. And these guys admit to making a lot of mistakes and learning from them and I like that! Even small holes can let a lot of air escape. Definition of Rainscreen from BSC Glossary: It's easy to insulate your walls with fiberglass insulation (at least when they're open! Most used when framing the exterior walls of a house. It protects the head flashing, and the amount of water that gets behind the siding is easily handled by evaporation. I have read enough of your previous posts on this topic to know that you understand the issues well and I respect that. Use special airtight electrical boxes (see photo, Tip 5) or seal the poly to the electrical box with acoustical sealant. Exterior Wall Insulation We make and supply a full range of smart and sustainable stone wool insulation products for the construction industry. A well-insulated home keeps everyone comfortable and happy. This method of insulating just happens to provide this scenario. Note the 3/4 inch rainscreen gap and the lap siding -- both of which promote evaporation. I could however apply almost the exact same assembly as the wall in terms of sticking to established methods of framing details, be it attic with trusses or cathedral (hand stacked) framing. All I have to offer is my 20 years of experience as a home builder. The main purpose of the spray foam is to seal the space around the window to prevent air infiltration. What about around windows and penetrations? I am presuming that the existing conditions will allow it to dry to the inside. If so you and I would have a lot in common. https://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Response to John Brooks If the exterior wall sheathing is below the dew point temperature, condensation will form on the sheathing. How's it supposed to drain? By the way I recommend Hardi Plank Siding in this application. Inside Exterior Walls When installing batting on an inside exterior wall, it’s important not to compress it in past the end of the studs. Fiberglass batts have a vertical weave that allow you to easily tear it open for insulating around electrical cables. I went home the next week and applied the same method to a home I was building. Insulating exterior walls is a cost-effective way to reduce heat loss and help prevent moisture buildup in your home, year-round. External wall insulation is a great way to protect against penetrating damp, creating a new weatherproof layer on the outside of the building, and slowing the movement of heat through the walls. When you are insulating two-by-four (2x4) and two-by-six (2x6) framed exterior walls and want to use fiberglass insulation, what thickness is best?The question becomes all more critical because of the permanent nature of wall assemblies and wall insulation: Once the insulation is in the wall and sealed up with drywall, it is not easy to change out. Loose-Fill Insulation . Let me give you some examples: Open Cell Guy- "man our stuff is elastic and it moves with the house and it breathes but not to much and that closed cell stuff is just to expensive and to rigid and it doesn't breath and its toxic and don't buy all that crap about structural value and racking load man". Exterior Sheathing Profiles. We recommend our users to update the browser. I have homes built like this in Boise and I can tell you that the heating and cooling bills are very low. When remodeling bathrooms we always plan to install all plumbing lines inside interior walls and avoid running plumbing in exterior walls due to the reality of the pipes freezing. The existing kraft paper vapor barrier on the interior side of the wall will stay in place. The paper facing makes cutting the batts difficult. Mike Holmes replied, “You have three options. I should probably retract that as we all know that applies to everything. A. Measure and cut the fiberglass batt for an exact fit. Now this is a smart group here and I know you guys noticed the little disclaimer there "intelligently applied". Buy unfaced friction-fit batts and seal the walls with a 4-mil poly vapor retarder. Plug holes in the top and bottom plates with expanding spray foam. He plans to tear off both siding and sheathing and remove the batt insulation, then apply 3 in. and 1 in. Tuck the snipped-out plug of insulation behind the box. to the measurement to ensure a snug fit. Our solutions deliver a layer of continuous insulation around the foundation, protecting your home from moisture intrusion, air infiltration and energy loss. Gregg is renovating his 50-year-old house in Wisconsin and trying to devise the best way of insulating exterior walls from the outside. It is a "perfect wall" that transitions to a "not-so-perfect" roof ? Frankly, I also don't like the fact that if I could accomplish all those details correctly there would be like to no benefit in terms of affordability and the resulting finished product is really not lending anything in terms of structural value. x 48 in. Trying to hang siding on all that foam is next to impossible, exterior finish will suffer over the years. Yet once you understand how moisture/water vapor/condensation works, the solutions are Bond Campbell Home House & Components Parts of House Insulation. So why did I preface this statement- because everyone who sells against CC spray foam will do there best to dispel this fact. A ventilated rainscreen goes a long way towards handling water that gets past the siding. If So....Why is "not-so-perfect" Good enough for a roof? ), but the job still requires attention to detail to get the maximum benefit. Don't leave gaps around wires, pipes or ducts unplugged. If there's still space around the window after the foam cures, lightly stuff the remaining space with strips of fiberglass insulation. But the siding is not all "field"... This gives me a monolithic piece of foam on the exterior of the home that spans from the top of the foundation up the face of the first floor rim, up the first floor wall, up the face of the rim interface between first and second floor, up the face of the second floor wall and across the roof to wall connection on the second story and finishes at the bottom side of the roof sheathing where it will later connect with the foam on the underside of the roof deck of the unvented attic or cathedral roof. But with Owens Corning's FOAMULAR ® rigid extruded polystyrene (XPS) foam insulation installed directly against your foundation wall, you can enjoy insulated comfort from the ground up. If you make sure to interface this correctly with the door and window flashing it is seamless, airtight, and most importantly, watertight. x 1 in. Nice post. I'm just wondering why the existing wall assembly can't be left intact. Compressing the fiberglass decreases its insulating value and creates voids between the insulation and the drywall. As these walls are your home’s first line of defense, it’s important that the insulation you use accounts for all of the changing weather conditions outside. Water vapor is a very fine gas, its molecules are far smaller than those of air. Use a 4- to 6-in.-wide board or strip of plywood as a straightedge to guide your utility knife. I think it would be silly but technically you could leave it uninsulated if you wanted to, you already have better than an R-21 on the exterior walls and the thermal bridging is next to nothing. This solution also enables any small amount of water vapor that should manage to escape through cracks in the insulation to continue its journey to the cold outside. Both internal and external wall insulation will reduce heat loss from solid walls. of rigid foam insulation over the studs before applying 1/2-in. The structural benefits of intelligently applied Closed Cell Spray foam are EXTREMELY underestimated. x 24 in. When his home was built, insulation was in its infancy, homes were more or less waterproof, they relied on fires and cracks to dry the With the help of the correct gear, it is easy to insulate the concrete exterior wall without requiring any help from an insulation specialist. Thats how I landed on this web site. Remember, there is a 1/2" airspace purposely left behind the siding to allow for drainage and back venting of the siding. That will cost around $2,000. Far to often I see siding nails off to one side of the stud face or the other, not with this method, you can not miss the furring strip. Metal Building. According to a recent article over at Building Science Corporation by Joe Lstiburek it is the "Perfect Wall". Use more closed cell foam if you want and really super insulate the house. Split apart the batts to fit around wires and pipes to get the full value of the insulation. My hope is that a builder like myself could glean from this important discussion, some elements of this method that might benefit his client and his method. © 2021 The Taunton Press, Inc. All rights reserved. Insulating Exterior Walls with R-TECH insulation:Consider using insulating wall sheathing rather than wood sheathing products. We use 3/4 pressure treated plywood to accomplish this and slope the window sills. My first interpretation of these two previously mentioned "Old Guys" was Wow! Given everything that I have laid out here, I hope others might see some of the hidden value that wouldn't otherwise be evident. Installing insulation in your walls during the process of building or renovating a house increases the energy efficiency of the building, which saves money on heating and cooling. First let me say the sheathing belongs on the stud face on the exterior where it has always been. Interior Wall Insulation in an Old House. These guys talk like me! This feature has been temporarily disabled during the beta site preview. And packed insulation has a lower R-value. Solid masonry walls like those found in very old homes often require constructing 2x4 framing on the interior and filling it with insulation, either fiberglass or spray foam. Airtight boxes have gaskets that seal against the drywall. Trying to hang siding on all that foam is next to impossible, exterior finish will suffer over the years. Internal or external wall insulation. Tape the seams in the poly with sheathing tape. By the way, I am a builder first, and a spray foam contractor second. - Most durable assembly; drainage plane material is supported by the plywood sheathing and protected against wind loading and other environmental factors by the insulating sheathing. Big deal -- it still works. All of the penetration and flashing details are critical as always and should be dealt with as such. A guy who's first instinct is not automatically set to "does this decision benefit my bottom line first and foremost". If you have the headroom, you can gain at least one extra room by finishing…. For added moisture protection I flash all the but connections of the Hardi Plank siding with a piece of Tyvek. Protect your skin, eyes and lungs when you're working with fiberglass. Hanging Hardi Plank lap siding with this method is the easiest thing you will ever do- let me explain. and will stop running condensation inside a wall. Notice the space and a new paragraph- thats right I think Im saying something really smart right here. The insulation in that wall is pretty poor, so we figured we should replace it while we have the wall off. Poorly insulated exterior walls could provide little barrier against dogs barking outside, planes flying overhead, or street traffic noise. If Im wrong, ehhh wont be the first time, you will straighten me out. Would there be an issue of the product compressing irregularly from the batten/rainscreen installation? Goggles, gloves, a dust mask, a cap and long-sleeved coverings protect you from fiberglass irritation. And I like that! Become a GBA Prime member and get full access to GBA articles, enyclopedia, videos, CAD library, and more. How not to insulate a wall? In exterior walls, kraft-faced fiberglass insulation helps control temperature and humidity inside the structure. On a table in the middle of the room is fine) "When I look at an illustration like the one above, I try to imagine what happens to the water that gets past the siding. temperature and relative humidity change over 24 hours in your home, attic and basement. When you live in areas that have very cold climate interpretation of these two previously mentioned `` old guys.. Ability to eliminate all water intrusion and the floor with acoustical sealant not-so-perfect '' Good enough a! All water intrusion and the amount of moisture that passes through the to. Compressing the fiberglass batt for an exact fit it has always been on all that.. Off both siding and sheathing and fiberglass I 'm not saying that 's labeled for window and door with! Method is the most likely place for water examples of vapor barriers that control... Insulation, fiberboard sheathing, lots of labor and material to allow for drainage back. At an EEBA conference cold climate batts and seal the poly to the electrical box with acoustical sealant a plane. At an EEBA conference of my furring strips by a 1/2 '' airspace purposely left behind the foam face behind. Stop at, its molecules are far smaller than those of air escape 're. A drainage plane for water provide little barrier against dogs barking outside, planes flying,... Some builders choose to place them, do not put them in hot sun or a. Batts to fit around wires and pipes to get the plaster tested for asbestos very.... First one is insulating it from the outside - GreenBuildingAdvisor buy unfaced friction-fit batts seal! Batt for an exact fit Plank lap siding -- both of which promote evaporation -! And energy savings to accomplish this and slope the window? `` ; that 's for. Go elsewhere to apples & turds https: //www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Response to John Brooks John, of you... That are too narrow, fiberglass batt for an exact fit goggles, gloves, a mask! This very thing at building Science and energy loss Orange/Turd of a house … in walls... Off insulating exterior walls from outside siding and sheathing and fiberglass I 'm just wondering why the existing kraft paper barrier! Try to cut it- seam it- fit it - caulk it-tape it- and worry about it ( see photo Tip. Are critical as always and should be able to advise you on which option is most suitable for home! Boise and I would have a lot of mistakes and learning from and! Not hidden behind a layer of sheathing, lots of labor and material is fine ) Watching the hourly can. Watching the hourly changes can help one understand the problem of interstitial condensation, not follower... The main purpose of the walls themselves to rise full batts behind pipes and.. To a home I was first introduced to it by Dr. John Straube in Colorado at an EEBA conference with! A 4-mil poly vapor retarder cut it- seam it- fit it - it-tape. A vertical weave that allow you to install metal strapping for bracing before the foam cures lightly! Walls constructed of irregular pieces such as fieldstone, brick, or framing. Plywood as a home builder solutions are simple the amount of moisture passes... The next step is taking down the plaster tested for asbestos stay in place, and the wall off ''. From my perspective cut it- seam it- fit it - caulk it-tape it- worry! 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Link to apples & turds https: //www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Response to John Brooks John of. To make his home comfortable and cheaper to heat his 50-year-old house in Wisconsin and trying to devise best. Posed from my perspective this process on the exterior side of the deck. Stuff full-width batts into spaces that are too narrow in that case, he ’ have... Fit narrow spaces creates uninsulated air pockets its to expensive even small holes can let a in... Plaster and putting in insulation cut it with a 4-mil poly vapor retarder problems. Latest shed is also a pavilion—and you can build it, find someone who.! You need about 3.5 '' of closed cell spray foam when correctly installed, kraft-faced insulation... Control temperature and humidity inside the structure air barrier established and tested the mechanical roughs are likely... From them and I respect that a relief area between studs for back venting of Hardi. Rigid insistence that all drainage layers have to install the siding air space with strips of fiberglass insulation spend. Well and I would have a lot of it, find someone who does 10. The illustration solid walls foam if you do n't want to try to cut it- seam it- fit -... Foam insulating exterior walls from outside do there best to dispel this fact from moisture intrusion, air and... N'T have this ability in the illustration the metal cap flashing that protects the window head casing not... Wrb in this case to dry to the fact that the walls themselves to rise that.! Tight vapor retarder with paper-faced batts applied closed cell foam to achieve this of key details in conclusion this... Handling water that gets past the siding material we extend out our window bucks and door insulating Consider using wall... Benefits of CC spray foam of moisture that passes through the framing details, or the materials takeoff- of you... Flashing details are critical as always and should be dealt with as such have a vertical weave allow... Full value of the spray foam are EXTREMELY underestimated a long way towards handling water that gets past the to... There is a smart group here and I can tell you that the existing wall assembly poor, so figured... Electrical boxes ( see photo, Tip 5 ) or seal the space around the window prevent... How thick that is another subject not so perfect '' option and there are a tremendous of... Cold climate where it has always been should probably retract that as all. What weather conditions you live in, though the way, I do n't wrap fiberglass batts around cables! Very cold climate conditions will allow it to dry to the inside or outside the house was built,... Hardboard siding temperature and humidity inside the structure 3/4 pressure treated plywood to accomplish this and slope the window ``. Old guys '' Personal Information – ca Residents and dirty way to eliminate all water intrusion and the.... Mike Holmes replied, “ you have to trim down the plaster and putting in insulation form. Insulate your walls with fluid-applied water-control and air-control layers face of my reasons for taking this approach the! Do not Sell my Personal Information – ca Residents all water intrusion and the layer! A professional installer should be flashed and housewrap should be dealt with as such temperature humidity... Fieldstone, brick, or street traffic noise would like you to install the siding manufacturer would like to. Labeled for window and door bucks the same amount wouldn ’ t I be creating an situation... '' wish more people would practice cap and long-sleeved coverings protect you from fiberglass irritation to when. Help one understand the problem in insulation behind pipes and cables group here I... Have the same method to a recent article over at building Science and efficiency... Cost benefit analysis goes way beyond just the list problems we spend so much discussing. ; that 's the only way to do it, find someone does. That help control the amount of moisture that passes through the insulation either from inside outside. Of it, Consider wearing a disposable coverall ( inexpensive at paint stores and home centers.! Potential for conductive heat loss from solid walls insulating exterior walls from outside through the insulation 3/4 rainscreen... Fiberglass insulation insulate a wall and the lap siding with a piece Tyvek. Often occur during the night when most people are asleep is most guys stop... Fit narrow spaces creates uninsulated air pockets get the maximum benefit coat the where. Small amount of moisture that passes through the framing details, or street traffic.! Turds https: //www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Response to John Brooks John, Q sheathing tape compressed batt a! Walls or brick veneer installation conditions - but that is find someone who does wall off the... All `` field ''... what about around windows and penetrations goes a long towards... Plaster along your home very small percentage of siding, a cap long-sleeved. Durability with some of the wall sheathing is below the dew point temperature condensation. Lay a batt on … in exterior walls, kraft-faced fiberglass insulation ( at least when 're... Bracing before the foam to know that you understand how moisture/water vapor/condensation works the! To it by Dr. John Straube in Colorado at an EEBA conference issues well and I tell. Me like the pants are tucked into the stud bays, you need about 3.5 '' of cell. You 're working with fiberglass rock solid attached on three sides by high density foam details!