The owner of a house built with traditional sheathing wants to air-seal and insulate the exterior walls. They have tried various methods to do so, including spray foam and Owens Corning Energy. To replace a small piece from the inside, they suggest using a tow kick saw and cutting it and gluing and screwing a new one. The challenge lies in connecting the exterior sheathing air barrier on the walls to the interior drywall air barrier at the ceiling. A simple plywood cap plate (3/4 in.) can be used to connect the exterior sheathing air barrier on the walls to the interior drywall air barrier at the ceiling.
To avoid CCSF, the exterior walls will be covered with 30 felt, Henry Blueskin, or 1″-2″ EPS on the inside of the sheathing. Rock wool or other insulation materials will be used for the walls. A recent project used Zip System R-Sheathing for a combination of weather resistive barrier, air barrier, and exterior insulation.
If a section of sheathing has succumbed to rot, it is crucial to fix it immediately. For a one-story house, the sheathing should extend from the bottom of the lowest framing member to the top of the highest framing member. For multi-story buildings, the sheathing on the bottom should be covered.
To completely air seal, spray with foam insulation or latex foam sealant. Other methods include sprayable caulk, construction adhesive, sheet foam, spray foam, fluid-applied membranes, and tape. To achieve full perimeter nailing, block and nailed off the horizontal seam between the sheathing and foundation with 3M polyurethane concrete sealant.
📹 Air Sealing and Caulking Walls
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How do you seal exterior sheathing?
Construction adhesive is a traditional method used to prevent future floor squeaks by applying dabs of adhesive to the top flange of floor joists. It is also used during the framing stage to seal joints of the subfloor and wall sheathing. A continuous bead of adhesive is applied along all four edges of the subfloor and along the outer face of top and bottom plates and each stud where a sheathing joint will occur. Before standing up the wall, another bead or two beads can be placed under the bottom plate.
This system uses inexpensive materials and is accepted by framers without objection. Blower door tests conducted several years after construction support its durability and low cost. However, not everyone is a fan of construction adhesive due to its rigidity and potential deterioration over time. Other options are available to address these concerns.
What can I use to fill gaps in OSB board?
The text posits that the use of foam can prevent the passage of air, moisture, or insects through the board. Alternatively, the gap may be filled with Bondo prior to the installation of the board. Additionally, the text suggests laying down LVP (20 mil wear layer thickness) directly on top. However, the planks may not be significantly affected by a small piece missing if the rest of the floor is flat.
What is the best fastener for OSB sheathing?
Screws are the preferred choice for OSB and softwoods due to their ability to prevent splitting and easy removal, which can damage the subfloor or sheathing. Applying OSB subfloors with nails is more likely to cause creak. If you have any questions about OSB screws, our team is available to answer them and suggest the best option based on your specific needs. Contact us at 610-376-5751 for more information on fasteners, manufacturing practices, and additional services.
Do you nail or screw exterior sheathing?
Exterior Jobs Nails are a popular choice for roofing, siding, and sheathing projects due to their lower price point and the need for fasteners. However, there are better times to use nails vs. screws. Historically, nails were chosen over screws due to their quicker fastening in place. Advancements in tool technology, such as electric and pneumatic screwdrivers, led to an increase in the popularity of screws.
The cordless drill/driver, the most popular portable power tool ever invented, also played a significant role in the popularity of power-driving screws. Both nails and screws have their advantages and disadvantages in various applications and situations.
How do you seal OSB for exterior use?
To protect OSB from water, apply a high-quality sealer by soaking the paintbrush tip in the sealer and brushing it over the ends and surface of the board. Repeat this process on both sides, not just the areas where cuts were made. Allow the seal to dry for 12 to 14 hours before coating the remaining surfaces. If more layers are needed, allow each layer to dry for 12-14 hours before adding the next. Test the waterproofing by pouring water on the board and allowing it to sit on the surface for a few hours. If the board doesn’t soak, add more layers and let it dry before testing again.
What is the best thing to waterproof an OSB board?
Sealants are essential for DIY projects and treating OSB panels, as they provide a reliable moisture barrier and protect them from water damage. OSB, or Oriented Strand Board, is an engineered wood panel used in construction for sheathing walls, flooring, and roofing. However, it is vulnerable to moisture, leading to swelling, warping, and eventual deterioration. Waterproofing your OSB is crucial, especially in the UK’s damp climate and humid conditions. Properly applying waterproof techniques ensures the longevity of your construction project and protects your investment.
Should you tape OSB seams?
The use of sheathing tape is of paramount importance for the maintenance of the structural integrity and optimal functionality of the building envelope, particularly in instances where exterior OSB panels are present. The LP WeatherLogic® Air and Water Barrier System provides an effective sheathing tape, an AAMA 711-13 approved acrylic tape, with high-quality adhesives that can withstand temperature cycling and provide consistent long-term protection.
What is best for sealing exterior plywood?
Epoxy sealers are a prevalent technique for sealing and waterproofing plywood, imparting augmented strength and protection to the wood. In addition to their sealing properties, epoxy sealers can also function as an adhesive, thereby extending the lifespan of the wood to which they are applied. Furthermore, they can be used as a primer for painting after sealing.
How do you fasten exterior sheathing?
Secure the sheathing with 2 ½ inch 8p ring nails every 6 inches, starting at the top left corner and fastening it to the vertical side stud from top to bottom. Fasten the top part to the top horizontal stud until it reaches the vertical stud adjacent to the vertical side stud. Fasten the bottom part to the bottom horizontal stud until it reaches the vertical stud adjacent to the vertical side stud. Fasten the panel to the first vertical inner stud, moving from top to bottom. Repeat steps until the panel is secure along all studs of the frame.
Cut holes into the sheathing for windows and doors by drilling a 1/2-inch wide hole into each corner of the door and window frames. Wear goggles and cut the sheathing along the edge of the frame with a reciprocating saw. Saw through the sheathing until all four sides are cut. When cutting a door hole, instruct a fellow worker to hold the sheathing inside the door frame to prevent it from falling or tearing away from the wall frame.
Should OSB sheathing have gaps?
The American Society of Appraisers (APA) recommends a 1/8-inch space between panel edge and end joints for plywood and oriented strand board (OSB) to minimize expansion and buckling, which can lead to costly and time-consuming callbacks. To ensure best performance, follow these panel spacing and nailing recommendations for APA Rated Sheathing, APA Rated Sturd-I-Floor®, and APA Rated Siding. Spacer-type panel edge clips may be used for roof sheathing applications.
Panel spacing is not a requirement, and some manufacturers may require a space during installation. Panel buckling may be an aesthetic or serviceability issue, not a structural deficiency. Gaps initially present may have closed due to normal moisture-related expansion. If the flatness of sheathing or flooring panels is acceptable, APA generally recommends installing finish flooring, siding, or roofing as planned, regardless of gaps present.
How to fill OSB gaps?
In the event of a gap between OSB sheets, it is recommended that latex paint caulk be used for smaller gaps, while foam filler rope is more suitable for larger gaps. The surface should then be coated with painter’s caulk. In the words of Lt. Gen. Russel Honore, one should avoid becoming mired in trivial matters, for a hen is merely an egg’s means of producing another egg.
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I sprayed primer on the back of my bare 1870’s siding, used high density R-15 fiberglass batts and a plastic film vapor barrier. I was worried about our NC humidity, and thought about not caulking a siding overlap top and bottom, but didn’t. Took all the paint off the outside, sanded & scraped to fresh wood (not gray), brushed on 50/50 linseed oil/thinner, then primed and painted. Biggest problem in 18 years has been the window sills. And my back.
I’m a little late to the party, but wanted to send a huge thanks for posting this article. Currently dealing with a very similar situation in a 1942 East Texas home. Gutted the kitchen about two weeks ago and was literally walking out the door to go to the hardware store this AM to buy 6 mil plastic and kraft-papered fiberglass insulation. Second-guessed myself (and the guy from the local hardware store) and checked your website for related articles. Luckily found this one! Still went to the hardware store to check similar products/options, but didn’t find anything that resembled Delta Dry and wasn’t impressed with the alternatives to Delta Vent S. So, I am ordering the Delta products! Going to do this job right! Anyways… Keep up the great work and please keep those product recommendations coming. Sometimes knowing WHAT to buy is the hardest part. The rest is usually easy, thanks to proper/professional advice from people like you. Thanks for all you do, sir!
Matt, Thank you for posting about this old remodel, I’m currently renovating the bathroom and laundry room in my 1950’s slab ranch in Michigan because of mold and water damage and it’s super helpful. I watch every article and am trying to talk my wife into closed cell foam prices lol. Is there anywhere I could as a diy guy, get consultations for best practices?
Hey Matt, really like your takes on concepts that are new to me like vapors drive and air sealing. I’ve been in a dilemma weighing between allowing part of wall cavities to breathe, like how the scuba pipes were used in the top plate in this article, and reducing the effectiveness of fire stops. I am probably not understanding it fully and wanted to get your take on it. Thanks
Just found this. I’m planning to insulate a 40 year ould detached garage with 2×6 framing on a concrete slab. I’m planning to use Rockwool and then drywall the interior. After seeing this my biggest challenge is how to vent the wall cavity? I’m in Central Oregon with hot dry summers and with rainy and extremely cold (at times) winters Zone 5. I just plan to heat to 50F or so. Any suggestions would be great??!!
I have a similar (but different) situation with a historic coach house that I am turning into an insulated workshop and would love some advice. I want to keep the historic exterior board and baton siding but there is no weather barrier. The structure is not 2×4 framed though, it is a pole and beam structure. My plan is to make the structure stiffer by framing out in between the 20′ gaps between the poles. Can I use the simple mats and weather barriers against the exterior cladding before framing or do I need to frame it first as with this example? I am wondering if not having the framing in the way would give me an advantage.
Thank you!!!!!!!!!! This is 100% what I was looking for in order to retrofit a 1917 four square in Dallas. It was originally a covered porch that was enclosed and I had no idea what to do. The contractors I originally hired just put up rolled insulation and no moisture barrier and in a rain storm water got in and I had a mold problem. I have been searching all day for a solution. You are my new hero!!!! Now if I could only figure out how to make the sub floor run from wall to wall to fix the air gust problem….
Interesting. I have a 100+ year old house with no insulation and no vapor barrier in the mountains of North Carolina. So I was eager when you mentioned this article as upcoming in your last article. I love perusal your articles. I know your focus is Texas and the south. Some of your articles include asides about northern climates. I would really love to hear just a bit more in each article on this since you have such a widespread geographical audience. In this article, if this house were in the north, what would change for you, if anything.
My house is in the Austin, TX area and built exactly the same. Is there any issue with removing exterior trim and windows, wrapping over the old siding and installing new siding over that? Also, if the tar paper is in good shape, is there any need to do any of this, or can I just bat insulate and call it a day?
Matt Your articles are the best. Can I say that a little more introduction to the project would be really helpful. Like the diagnosis and then the cure. A brief overview would really make us understand the reasoning for all this. House style, owners interests, problems, codes, costs and cure. This looks like over kill but it could be in a swamp Thanks again for all your hard work on these articles. They are really informative and well done
the best way to cheat the cost of this scenario IS to spray a thin layer of closed cell foam insulation. you can achieve the goal of a moisture/vapor barrier in a 1/4 inch of foam. after go into the bay with encapsulated fiberglass insulation if you’re still concerned. Mike Cross Design and Construction
I don’t understand the piping that allows airflow from the crawlspace to the attic. If you use closed cell foam on the walls why would you need to vent? Also isn’t the attic going to be conditioned? Couldn’t you spray the crawlspace (if possible) – spray the walls and attic to air seal and call it a day?
Hey Matt, does this method vary for the cold Northeast? I have a cabin in the Catskills, we have mild summers with low humidity (due to elevation) and then very cold winters. Temps regularly dip into single digits. My thinking is that I’m less concerned about moisture from the outside than from inside. Do I still need an air gap on the outside? Seems a mositure/air barrier on the inside would serve me better.
Very confusing details, delta vent s is vapor permeable and then you mention with a stucco type cladding and mineral wool install you want to tape your delta vent to the studs to prevent vapor drive however this product is very vapor open at 50 perms. If there was a vapor drive scenario wouldn’t the water vapor push past the delta s and into the cavity to be absorbed by sheetroc/studs in a mineral wool installation ?
Hey Matt. I’m renovating my flat roof kitchen and I’m down to studs and rafters. I’m having to replace the OSB sheathing (nailed to the original T&G boards) and EPDM membrane. I’ve been in touch with Dorken (your articles introduced me to their products…thanks) and the Canadian rep I spoke with thought your wall application of Delta-Dry and Delta-Vent was sound. (I’m in Zone 6) but he wasn’t sure about me using the wall application for the attic. How would you insulate the 12″ deep attic when the original decking is currently visible from the kitchen?
What do you do when someone has drilled electric through the stud wall and plumbing lines over the past 50 years— I mean it’s pretty terrible. There was a water leak and the insulation they stuffed up there I just removed on the lower part of the wall, black mold and all. I used chromobium (sorry about the spelling) to kill it. The structure was an old holding area for horses on the Pony Express that was separated by shoddy 2×4 walls, creating two little apartments or bungalows, if you will, (or hot, horrible vapor ridden structures). I am in California and I will contact Dorkin. Thanks. Great advice on the article,
I’m about to tackle this problem in one bedroom in my home. I’ve cut 3/4″ x 3/4″ spacers to nail up tight against the siding in the corners of the stud bay to create the air gap. I’ll then place 1″ rigid foam boards the length and width of the bay over the spacers and foam them in place. The final step will be to compress fiberglass batts into the remaining stud depth.