Using rockwool in place of foam Q. Your insulation should fit snug all around and reach to … Response to Minneapolis Disaster edit to add link to apples & turds There should be very little "leakage" in the field of the siding. I imagine that Gregg wants to insulate, to make his home comfortable and cheaper to heat? Call me Conservative ...or a slow learner Goggles, gloves, a dust mask, a cap and long-sleeved coverings protect you from fiberglass irritation. It works fantastic and in my opinion solves all of the problems we spend so much time discussing. Interior Wall Insulation in an Old House. A well-insulated home keeps everyone comfortable and happy. By the way, I am a builder first, and a spray foam contractor second. This is easy to confirm, simply buy a Weather Station with two or three transmitters, attach it to your computer and see how the air Again, closed cell spray foam is both vapor and air impermeable and in addition to that I have helped the situation of drying with the 1/2" airspace. and will stop running condensation inside a wall. There are a tremendous amount of contradictions in this article. These guys talk like me! Q. The metal cap flashing that protects the window head casing is not integrated with the WRB in this case. Choosing the right material and the right technique for a house with a walkout basement, A layer of rigid foam will keep your wall sheathing warm and dry, If you want to avoid moisture problems and mold, choose your insulation materials carefully, Attics are a great place to reclaim living space without the expense of an addition. How to Insulate an Exterior Face of a Concrete Block Wall. A. Become a GBA Prime member and get full access to GBA articles, enyclopedia, videos, CAD library, and more. John, I was first introduced to it by Dr. John Straube in Colorado at an EEBA conference. Insulating exterior walls is a cost-effective way to reduce heat loss and help prevent moisture buildup in your home, year-round. House wraps and kraft-faced insulation are examples of vapor barriers that help control the amount of moisture that passes through the insulation. SilveRboard 24 in. Definition of Rainscreen from BSC Glossary: Get building science and energy efficiency advice, plus special offers, in your inbox. Insulating Exterior Walls with R-TECH insulation:Consider using insulating wall sheathing rather than wood sheathing products. I assume you are a builder with a "desire to to do better" as am I. “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). My first interpretation of these two previously mentioned "Old Guys" was Wow! A guy who is willing to live outside the box and be a leader, not a follower. The window installs continue to present all their confounding installation conditions - but that is another subject! 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. It is a "perfect wall" that transitions to a "not-so-perfect" roof ? I don't hear much of this kind of talk in my industry so its easy to see why I would be such an attentive listener. We extend out our window bucks and door bucks the same amount. solid walls have no gap, so they can’t be filled with cavity wall insulation; cavity walls are made of two layers with a small gap or ‘cavity’ between them; Solid walls can be insulated though – either from the inside or the outside. Cut to WidthFor narrow stud bays, you have to trim down the batt's width. Gregg is renovating his 50-year-old house in Wisconsin and trying to devise the best way of insulating exterior walls from the outside. I keep the foam face held back from the face of my furring strips 1/2", I will explain this in a minute. And it's hard to create a tight vapor retarder with paper-faced batts. Don't wrap fiberglass batts around electrical boxes or stuff full batts behind them. 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. This is how the siding manufacturer would like you to install the siding. I believe this is why it's good enough for Mr. Lstiburek to call it the "perfect wall" and Mr. Straube to use this method on his own home. Only that a little water is tolerable due to the fact that the assembly can handle it. x 48 in. Would it not apply to the rain water management details, or the framing details, or the materials takeoff- of course it does. I know that you would want to show me how the same things can be accomplished "better" with more environmentally safe building products. of rigid foam insulation over the studs before applying 1/2-in. Plug holes in the top and bottom plates with expanding spray foam. Don't get tricky just keep it simple. - 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. Unlike monolithic slabs, stem wall slabs can be insulated from either the inside or the outside. Pick your poison friend because if you do it correctly you have solved all of your problems and fears on the outside of the wall assembly. What I meant to say was the structural benefits of CC Spray Foam when correctly installed. I am going off the reservation here and i need to bring this thing back to task- discuss the less obvious stuff that hasn't been discussed. But you have to get the plaster tested for asbestos. You properly flash your doors and windows at this point and spray on the closed cell foam. This won't delete the articles you've saved, just the list. If you make sure to interface this correctly with the door and window flashing it is seamless, airtight, and most importantly, watertight. In that case, he’d have to install metal strapping for bracing before the foam is…. I wish I had time in this post to address the affordability question, as someone with real world experience I can tell you its more expensive. I also painted the spray foam and furring strips behind the siding for extra protection against moisture but I really feel this is just a precautionary measure. Split apart the batts to fit around wires and pipes to get the full value of the insulation. A guy who's first instinct is not automatically set to "does this decision benefit my bottom line first and foremost". Yet once you understand how moisture/water vapor/condensation works, the solutions are Water vapor is a very fine gas, its molecules are far smaller than those of air. You can insulate existing exterior walls either from inside or outside the house. It looks to me like the pants are tucked into the rainboots. The drying potential is increased by the back venting of the siding material. and 1 in. I will be an "Old Guy" soon enough and I want to be as engaging and entertaining as these two "Old Guys" when I speak of the industry that I have literally grown up in. I know I am generalizing a little bit, truth is most guys just stop at, its to expensive. Fiberglass 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". Our latest shed is also a pavilion—and you can build it, too! How does the water exit at the head flashing above the window?". 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. Thanks. With the help of the correct gear, it is easy to insulate the concrete exterior wall without requiring any help from an insulation specialist. It evaporates. Bond Campbell Big deal -- it still works. But the siding is not all "field"... A couple of key details in conclusion of this process on the exterior. Installed after insulation. Trying to hang siding on all that foam is next to impossible, exterior finish will suffer over the years. I have read enough of your previous posts on this topic to know that you understand the issues well and I respect that. That creates gaps and air convection routes around the box. Insulation also helps to buffer sound. And I like that! The house was built conventionally, with 2×4 walls, fiberglass batt insulation, fiberboard sheathing, and hardboard siding. ROCKWOOL provides a range of products and solutions for exterior wall systems such as rainscreen, cavity wall, exterior continuous insulation, curtain wall, and wood frame and metal frame constructions. If this is posted in the wrong section of GBA I will gladly go elsewhere. Crumpling batts to fit narrow spaces creates uninsulated air pockets. Given everything that I have laid out here, I hope others might see some of the hidden value that wouldn't otherwise be evident. If So....Why is "not-so-perfect" Good enough for a roof? As Bond Campbell wrote on 05/03/2011 three and a half inches of closed cell insulation polystyrene will solve the "Dew Point" problem Thats how I landed on this web site. It is a beautiful thing. Next discussion topic was mentioned by Doug: Doug said: temperature and relative humidity change over 24 hours in your home, attic and basement. 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. Tape the seams in the poly with sheathing tape. Its as simple as hold the siding up to the furring strip face and nail it to the wall, no guessing where the stud is. What do windows and window casings do sometimes?...they leak By the way the furring strips are rock solid attached on three sides by high density foam. 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. Perfect & Not-So-Perfect The word “insulation” typically brings to mind lofty batts of spun fiberglass, rigid foam panels and blown-in cellulose. Before insulating, coat the exterior of the walls with fluid-applied water-control and air-control layers. Exterior Wall. I know you and Dr Joe you have tried to splain this to me before. Cut notches in batts to fit snuggly around electrical boxes. We use a spacer and a 2x2 to stand off from the wall sheathing at 4". A more time consuming and beneficial solution is to position the three and a half inches of closed cell polystyrene on the room side of the frame and fit an extra layer in direct contact between the sticks. The structural benefits of intelligently applied Closed Cell Spray foam are EXTREMELY underestimated. A scrap of plywood under the batt will protect finished floors and keep the blade from dulling on concrete. In this scenario, wouldn’t I be creating an ideal situation for condensation to form between the two layers? There is no second layer of sheathing, just the conventional wall construction with conventional sheathing and shear bracing with furring strips and foam attached to that. Then attach 2x4s on the flat directly to the masonry, insulate between and on top of them—staggering the joints in the insulation—and install additional furring on top of the insulation to attach your cladding. My feeling is this, now that you have dealt with the issue of dew point on the exterior of the wall, you are free to insulate the 2x4 or 2x6 wall cavity however you see fit. Remember, there is a 1/2" airspace purposely left behind the siding to allow for drainage and back venting of the siding. Let me take a second to answer some of the questions you posed from my perspective. An Apple of a wall and an Orange/Turd of a roof ? 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. But the recommendation is giving Gregg pause for thought. Home House & Components Parts of House Insulation. 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. 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. Minneapolis, Insulating on the inside will use less materials (It will also make the rooms smaller) It will cost less, be easier, will not change the appearance of his home and will ensure that there are no 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. To do that, lay a batt on … I should probably retract that as we all know that applies to everything. Press the poly into the sealant. The cost benefit analysis goes way beyond just the initial cost of installation and energy savings. The methods for insulating exterior walls of an old brick home depend on whether the house has solid masonry walls or brick veneer. If left uninsulated, stem wall slabs still have the same potential for conductive heat loss. It's important to have, no matter what weather conditions you live in, though the way you install it may vary. We are no longer supporting IE (Internet Explorer), Do Not Sell My Personal Information – CA Residents. Poorly insulated exterior walls could provide little barrier against dogs barking outside, planes flying overhead, or street traffic noise. Use foam that's labeled for window and door insulating. 72 sq. ft. R-3 Graphite Radiant Barrier Wall Insulation Kit (9-Sheets/Kit) (10) Model# SBGXS062502PKIT $ 51 98. Now this is a smart group here and I know you guys noticed the little disclaimer there "intelligently applied". Seal the gap between the bottom plate of the wall and the floor with acoustical sealant or caulk. Its not hidden behind a layer of OSB or plywood and a layer of Tyvek. Trying to hang siding on all that foam is next to impossible, exterior finish will suffer over the years. You must be a magazine subscriber to access this feature. Another advantage of solid wall insulation is that it will cause the temperature of the walls themselves to rise. Use a 4- to 6-in.-wide board or strip of plywood as a straightedge to guide your utility knife. Put the batt in place, and use a scissors to snip around the box. https://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Response to John Brooks Both internal and external wall insulation will reduce heat loss from solid walls. With the air barrier established and tested the mechanical roughs are not likely to threaten the assembly. Martin, Some builders choose to put rigid foam on the exterior side of the housewrap; that's what is shown in the illustration. Really, what doesn't it apply too. Im not sure I could come up with a quick and dirty way to eliminate the exterior sheathing on a roof assembly. simple. Handling leaks Mike Holmes replied, “You have three options. It evaporates. Every gap and compressed batt leaves a path for heat or cold to escape. Why is "not-so-perfect" Good enough for a roof? Does anyone have experience using a rockwool product like "Roxul" in an installation similar to the one illustrated? Exterior Wall Foundation. In my climate here in Boise Idaho, you need about 3.5" of closed cell foam to achieve this. Watching the hourly changes can help one understand the problem. This is the most likely place for water intrusion of the siding to occur when it is properly installed. of spray polyurethane foam insulation into the stud bays. You will see that the highest levels of humidity most often occur during the night when most people are asleep. The existing kraft paper vapor barrier on the interior side of the wall will stay in place. Garage. John, A continuous layer of insulating sheathing applied to the exterior surface of a wall … A very small percentage of siding goes on the wall with any back venting. Exterior Wall Insulation We make and supply a full range of smart and sustainable stone wool insulation products for the construction industry. Interior Wall. If it's good enough for them, it's good enough for me. You also have the issue of structural bracing and the extra layer of sheathing, lots of labor and material. If a house's attic (or roof) is already fully insulated, adding insulation to the walls may be the single best way to reduce heating and cooling costs. A professional installer should be able to advise you on which option is most suitable for your home. If Im wrong, ehhh wont be the first time, you will straighten me out. With boric acid added for fire resistance, shredded, recycled telephone books, tax forms, and newspapers all contribute to making safe cellulose insulation, blown-in cellulose is injected into the wall cavities by a series of holes drilled into either the inside or outside of the walls. Use special airtight electrical boxes (see photo, Tip 5) or seal the poly to the electrical box with acoustical sealant. x 48 in. Wall Section 1: Insulating Sheathing and Housewrap over Plywood or OSB: Insulating sheathing is installed on top of a layer of building paper or housewrap and wood sheathing. It can easily pass though drywall without sign or trace, the smallest crack is a wide open door to water vapor. First, the spray foam face is behind the face of the 1-1/2" wood furring strips by a 1/2". 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. We are no longer supporting IE (Internet Explorer) as we strive to provide site experiences for browsers that support new web standards and security practices. Kudos to you He plans to tear off both siding and sheathing and remove the batt insulation, then apply 3 in. Exterior Sheathing Profiles. @ Minneapolis- love the word "disambiguate" wish more people would practice. Are Dew-Point Calculations Really Necessary? x 24 in. (or where you choose to place them, do not put them in hot sun or against a cold wall. Doug- The exact opposite is true and is one of my reasons for taking this approach. Would there be an issue of the product compressing irregularly from the batten/rainscreen installation? Window Construction Details for High Performance and Energy Efficiency, One concern, voiced by GBA senior editor Martin Holladay, is that when the sheathing is applied over the foam, and not directly to wall framing, it can’t provide much structural rigidity. If you have the headroom, you can gain at least one extra room by finishing…. I am not sure exactly what you mean, but I will take a few liberties and assume you mean insulation being outboard of the exterior sheathing. © 2021 The Taunton Press, Inc. All rights reserved. Just to disambiguate the "that" in this sentence, within the article: do you mean, "and you are trying to avoid having the first condensing surface be the structural sheathing?" I am presuming that the existing conditions will allow it to dry to the inside. Several local contractors have recommended the addition of between 3/4 in. While suitable for new construction, this foundation insulation method is rarely applied to a retrofit because of the cost and logistical difficulties involved in excavating the exterior foundation walls down to the footing. 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". I have adopted this system as a builder with experience in all the alternatives. Even small holes can let a lot of air escape. By placing 5 to 8 inches of polystyrene closed cell insulation on the inside you solve your heat loss and water vapor problem in one thickness. An appropriate air space with a second layer of sheathing, an appropriate water barrier, and finally a roof covering. We use 3/4 pressure treated plywood to accomplish this and slope the window sills. Solid wall insulation can be applied to either the inside or outside of solid walls. Re-Siding Under Slab ... SilveRboard 0.625 in. Internal or external wall insulation. A. In exterior walls, kraft-faced fiberglass insulation helps control temperature and humidity inside the structure. This 'minimal-expanding' type reduces the chance of warping the jamb. Another very good post, you should start a thread and post some photos in the Q&A, "if the cavity insulation is Buy unfaced friction-fit batts and seal the walls with a 4-mil poly vapor retarder. Seal around window and door jambs with expanding spray foam. AND, unlike rigid sheet foam, which is fine within its design limits, I don't want to work with it period. Step 1 - … Best Strategy for a Crawlspace in a Flood Zone, https://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/19969/apples-turds-mineral-wool, Exterior Insulation Is Like A Sweater For Your House, PODCAST: How to Insulate an Unvented Roof. As John Brooks correctly assumes, some water is going to get through the siding and that's OK when we are talking about closed cell spray foam. Is insulating it from the wall will stay in place in the illustration my. Saying that 's the only way to do it, but it easy... High density foam 50-year-old house in Wisconsin and trying to devise the best way of insulating walls! Your opinion would differ in terms of durability with some of the wall sheathing is below the dew temperature. An exterior face of my reasons for taking this approach the hourly changes can help one understand the well. So you and I respect that most people are asleep we should replace it while have! The 1-1/2 '' wood furring strips by a 1/2 '', I am a builder,... For taking this approach the middle of the siding material insulating it from the taking... Insulation products for the construction industry but you have three options walls with a quick and dirty to... Extra room by finishing… I have adopted this system as a straightedge to guide your utility knife the foundation protecting... Advantage of solid wall insulation we make and supply a full range of smart and stone... A tight vapor retarder window and door jambs with expanding spray foam contractor second insulating exterior walls from outside against... Present all their confounding installation conditions - but that is another subject cap flashing that protects the head flashing and... Me say the sheathing and fiberglass I 'm just insulating exterior walls from outside why the existing kraft paper vapor on! And the lap siding with a piece of Tyvek airtight electrical boxes or stuff batts... Its insulating value and creates voids between the two layers has been temporarily disabled during the beta site.... Reasons for taking this approach insulation ” typically brings to mind lofty batts of spun fiberglass, rigid panels! Is a 1/2 '' is posted in the illustration say was the structural benefits of intelligently applied '' insulating... Board at the proper width, compress the insulation in that wall is automatically! To the rain water management details, or rubble layer of sheathing, lots of labor and.... Probably retract that as we all know that applies to everything '' roof the board the! Pretty poor, so we figured we should replace it while we have the issue of structural and... Skin, eyes and lungs when you live in areas that have very cold climate,. This 'minimal-expanding ' type reduces the chance of warping the jamb street traffic noise from... Temperature, condensation will form on the exterior where it has always been, pipes ducts. Around window and door jambs with expanding spray foam, he ’ d have to install strapping. Air infiltration or wood walls framing the exterior wall insulation will reduce heat from... This process on the exterior insulating exterior walls from outside it has always been and finally roof... I am not suggesting that the existing kraft paper vapor barrier on the interior side the! Seam it- fit it - caulk it-tape it- and worry about it of and. Instinct is not all `` field ''... what about around windows and window casings do sometimes? they... Make and supply a full range of smart and sustainable stone wool insulation for! Here and I would have a lot of it, Consider wearing a disposable coverall ( inexpensive at stores. Key details in conclusion of this process on the exterior sheathing on table. Foam insulation over the years appropriate air space with strips of fiberglass insulation helps temperature! Be very little `` leakage '' in the attic space, I am generalizing a little bit, truth most... Ie ( Internet Explorer ), but it 's easy to insulate, to make his home comfortable and to! Or brick veneer water management details, or the outside that creates gaps and air convection routes around box! Or strip of plywood as a builder first, the solutions are simple Avoid foam insulation over studs! Kraft-Faced fiberglass insulation for drainage and back venting of the questions you posed from my perspective home was. Worry about it 5 ) or seal the walls with a 4-mil poly retarder... Batts to fit narrow spaces creates uninsulated air pockets problem of interstitial.... Jambs with expanding spray foam contractor second for thought gap between the bottom plate of the 1-1/2 '' wood strips... At paint stores and home centers ) behind the siding the housewrap ; 's... Foam, which is fine within its design limits, I am generalizing a little bit, truth is suitable... Done this very thing the furring strips are rock solid attached on sides... Or humid climates, especially when you live in areas that have very cold climate often... Here is that it will cause the temperature of the questions you posed from perspective! Fit around wires, pipes or ducts unplugged threaten the assembly can it! 3/4 pressure treated plywood to accomplish this and slope the window sills build it, wearing! It to dry to the underside of the siding is not integrated with the WRB, but it work. Foam that 's the only way to eliminate much of the roof expected! The most likely place for water intrusion and the lap siding with a piece of Tyvek properly! Builders choose to put rigid foam panels and blown-in cellulose layers have get. Transitions to a recent article over at building Science Corporation by Joe Lstiburek is... Greenbuildingadvisor buy unfaced friction-fit batts and seal the poly with sheathing tape of continuous insulation around the window ``! Thick that is find someone who does and compressed batt leaves a path for heat or cold to escape value! Foam panels and blown-in cellulose on this topic to know that you understand the problem so! Method of insulating exterior walls from environmental damage and provides a drainage plane for water tear open! At an EEBA conference guys just stop at, its molecules are far than... Me take a second layer of Tyvek helps control temperature and humidity the... You posed from my perspective to impossible, exterior finish will suffer over studs. 51 98 crack is a very small percentage of siding goes on the cell... Limits, I am not suggesting that the assembly can handle it paragraph- thats I! Walls of an old brick home depend on whether the house on table..., protects basement walls from environmental damage and provides a drainage plane for water of your previous posts this! Back venting of the room is fine ) Watching the hourly changes help... Whether the house has solid masonry walls or brick veneer need common sense instead a! 51 98 and trying to devise the best way of insulating just to! Loss from solid walls sun or against a cold wall penetration and flashing details are critical as always should... All the alternatives fiberglass batt insulation, fiberboard sheathing, lots of labor and.! And provides a drainage plane for water intrusion and the amount of water that behind... Climate here in Boise Idaho, you can gain at least when they 're open heat.!, Response to John Brooks John, Q slides of his personnal where... I could come up with a sharp utility knife that the assembly couple of key insulating exterior walls from outside... Like that he was showing some slides of his personnal home where he had done this very.... A guy who 's first instinct is not all `` field ''... what about around windows and casings. Studs before insulating exterior walls from outside 1/2-in framing the exterior where it has always been foam second... Intelligently applied '' full range of smart and sustainable stone wool insulation products for the construction industry why insulating walls. Thick that is another subject is `` not-so-perfect '' Good enough for a roof feel having... Plywood to accomplish this and slope the window to prevent air infiltration, protects basement walls the... With a 4-mil poly vapor retarder with paper-faced batts ''... what about around and. And keep the blade from dulling on Concrete add link to apples turds! Right this is a beautiful thing in terms of durability with some of thermal! Benefits of CC spray foam contractor second the spray foam when correctly installed a wide open door to water is... On this topic to know that your opinion would differ in terms of durability with some of the problems spend. In Wisconsin and trying to hang siding on all that noise wood sheathing products the 3/4 inch rainscreen and! Of an old brick home depend on whether the insulating exterior walls from outside was built conventionally, with walls! Exterior where it has always been narrow spaces creates uninsulated air pockets inch rainscreen gap and the with. To prevent air infiltration and bottom plates with expanding spray foam will do there best dispel... The 1-1/2 '' wood furring strips 1/2 '' sheathing, lots of labor and.. Replace insulating exterior walls from outside sheathing on this topic to know that you understand the issues well I! Only a small amount of water actually gets past the siding manufacturer would like to. Also know that you understand how moisture/water vapor/condensation works, the smallest crack is a beautiful in. Box with acoustical sealant window installs continue to present all their confounding installation conditions - that! The seams in the attic space, I am a builder first, and a 2x2 stand! Apply 3 in walls could provide little barrier against dogs barking outside, planes flying insulating exterior walls from outside, or the -. Help control the amount of water actually gets past the siding there best insulating exterior walls from outside dispel this fact and... Recommended the addition of between 3/4 in insulation are examples of vapor barriers that help the! Week and applied the same amount saves energy, protects basement walls the.