How can I protect the OSB sheathing from rotting in the rain? Get a moisture meter and keep an eye on it. Would it make sense to paint the edges of those that I've cut? --Seth P., Titusville, Fla. DEAR SETH: Here's the good news. As far as your 3" hardwood goes, If the floors dry and the delam parts removed, I don't see any problems, but Flor might be a better person to answer that. The house I’m building in central Arizona has a subfloor of 23/32″ Norbord Truflor OSB on i-joists over a ventilated crawlspace. Under the best circumstances, the OSB sheathing is delivered to the site, installed and covered within a few days. To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion. You don't want to wrap the lumber like you would a sandwich with plastic. Even with standard 3/4 OSB T&G decking, if the frame goes up rapidly and it gets sheltered in a reasonable amount of time, there won't be problems. The wood rot you're familiar with happens in the presence of water and oxygen. Some types of OSB subflooring have drainage grooves that prevent rain from ponding on the surface, minimizing contact with moisture and therefore reducing the necessary drying time. How to Protect Plywood From Water Damage. Wood rot can and will start when the moisture content of the wood reaches 20 percent. How to protect a shallow monolithic footer during winter construction, zone 5, Residential PV Installations in Florida Remain Strong. Painting the subfloor won't cause any problems, but it's a waste of paint. You mix up the oxygen bleach and apply it with a garden hand-pump sprayer. It's great to know that the paint wouldn't cause any problems. Once the lumber is clean and dry, you can then decide if you want to prevent wood rot in case the wood somehow gets wet after you move in. This is one good reason why good construction includes good organization and scheduling. Protecting subfloor from water during construction We're building a tiny house on a trailer, in Florida, during the rainy season. It needs to breathe. On average OSB costs less than standard plywood by 10-15%. I’m building by myself and very slowly, so it might take me three months before I have walls and a roof. Acting quickly, therefore, means that your job of drying out the subfloor will be that much easier. My builder says this is normal and I still get my 10-year warranty. But wood rot is a slow process where the fungi start to grow and feed on the cellulose in the wood. Step 3 Apply water seal to the surface of the plywood. Step 2 - Plan and Cut Your Pieces Every time you make a cut, any sealer at the edges will disappear and open up a new place where moisture and water can be absorbed. The important factor is making sure the inside of your walls are dry before insulating and sheetrock (. OSB takes longer to get saturated with water than plywood, but it also takes longer to dry out once it gets saturated. You want all the lumber to dry out as fast as possible after each rain… All OSB is made water resistant to a point, but every little bit will help your overall result. and even below the underlayment, in some cases. Huber AdvanTech comes in subfloor and Sheathing panels. Your new layer of underlayment needs to be perpendicular to the joists just like the subfloor is. Plywood, or even OSB, has its strength running with its length. In fact, the coating on this tried and tested sub-floor helps reduce water absorption by up to 40%. I'll grant you it had a protective layer of bark that works very well to protect the wood in the center of the trunk. You can also watch hundreds of videos, download Quick Start Guides and more, all for free.) In fact, rain storms left standing puddles of water on my own home's plywood sub-floors for days. The usual fix is to attack your subfloor with a belt sander after the roof is on, and to replace the worst of … Using Ever Build - Black Jack All Weather Roof Coating - To seal OSB Board. Standing water on the OSB needs to be swept away. Available in: Enhanced, Tolko T-STRAND™ Pro OSB T&G subfloor; Standard, Tolko T-STRAND™ OSB T&G subfloor . On average, my location will get 6 days/1.2 inches of rain in March, 3 days/0.7 inches in April, and 2.1 days/0.3 inches in May. Someone just told me that if I paint the top of the OSB, moisture will get trapped inside it, because if the dry, top side facing the sun is sealed, and the side facing the moist air of the crawlspace is unsealed, moisture will try to migrate from the moister, crawlspace side to the drier, top side, but get trapped underneath the paint. The glues used to make OSB are water-resistant because the … Acting quickly, therefore, means that your job of drying out the subfloor will be that much easier. He consistently checked for water absorption and joint displacement since he previously used standard OSB and plywood. However, this option is only feasible if wall framing has not been erected. This debris can trap water and hold it against the OSB. All scraps of lumber, sawdust, etc., need to be off the OSB. All OSB is made water resistant to a point, but every little bit will help your overall result. You want the sides of the stacked lumber exposed to the air but protected so rainfall can't hit the lumber. Sealed OSB. Plywood is one of the most commonly used construction materials in the residential and commercial areas. I've never used Truflor, so I don't know how resistant to moisture the product is. FAQ: Why Do Some Builders Avoid Foam Insulation. Improper spacing. It might rain for the next few days. In fact, the coating on this tried and tested sub-floor helps reduce water absorption by up to 40%. You want the sides of the stacked lumber exposed to the air but protected so rainfall can't hit the lumber. Every wood subfloor over a crawl space should be tested for moisture. Newer building products are available for subfloors that contain resins that protect the wood fibers from absorbing any water. Become a GBA Prime member and get full access to GBA articles, enyclopedia, videos, CAD library, and more. CLICK HERE to get FREE & FAST BIDS from local rough framing carpenters. You can also use chlorine bleach, but many complain about its fumes and toxicity to nearby plants and vegetation. The plywood was not affected long term because I used the right grade. This type of board is an excellent material for use in waterproofing systems, be they roof, sub-floor or wall. Wear eye protection and a dust mask when sanding OSB to avoid injury from any splinters or sanding dust. This debris can trap water and hold it against the OSB. Re: Subfloor And Rain You need to allow it to dry well before you can tell any extent on damage, then chect the joints between the sheets, thats a likely place for the ply to push up. The subfloor continues to dry and the flooring starts to buckle because the fullness created by the subfloor shrinkage now has nowhere to go. The OSB floors should be swept clean each day after work concludes. Mock’s crew had to shovel snow off the deck then squeegee water off it over the course of the build. You can purchase some Listerine and mix it 50/50 with water and put it in a spray bottle. Some OSB panels are created that have drainage slot in the tongues to help get rid of water. Q. (c)2015 TIM CARTER DISTRIBUTED BY TRIBUNE CONTENT AGENCY, LLC. Houses under construction get rained on all the time. This is one good reason why good construction includes good organization and scheduling. Jeff, Fastener Holding Compared to PS-2 panels, AdvanTec… Thank you, Martin. OSB subfloor is mostly serving as a base under the finish floor (hardwood, engineered wood, vinyl tile, etc.) Does my dry climate compensate enough for my slowness in building that the OSB should endure the time it will take me to get it out of the weather? DryGuard® Enhanced OSB roof sheathing panel is a Structural I rated sheathing offering improved moisture resistance from the elements throughout the panel. Step 3 Apply an outdoor, latex-based paint to plywood in order to provide more protection that will have a more aesthetic appearance than traditional stains. The OSB floors should be swept clean each day after work concludes. You must be a magazine subscriber to access this feature. It's unlikely you will need to replace any of the OSB subfloor for structural reasons. The OSB floors should be swept clean each day after work concludes. To address these water issues, OSB and plywood manufacturers are refining their products. Rain rot cures: it is a fungal bacteria that thrives in the moist dark environment. However, this option is only feasible if wall framing has not been erected. Additionally, care must be taken to prevent water from collecting under the tarp. Timbered logs are routinely salvaged that never made it to sawmills over a hundred years and these logs are prized pieces of wood. DryPly® plywood Sturd-I-Floor® panels feature a water-repellent coating that provides excellent weather protection during construction. Preventing subfloor puddles in the first place: Plastic tarps spread on the floor deck prior to rainfall are the best prevention against the accumulation of standing water. It rained today and my house is very very wet including everything inside and the basement. Next time, invest in Advantech. This debris can trap water and hold it against the OSB. Don't interior finish until the moisture in the wood has stabilized! 2. Preventing subfloor puddles in the first place: Plastic tarps spread on the floor deck prior to rainfall are the best prevention against the accumulation of standing water. Sanding seams is necessary on most jobs due to the tendency of OSB to swell at the edges (coincidentally known as edge-swell) when exposed to rain, snow, or construction-related moisture introduced during the construction process (which also reiterates the need to check the moisture of the subfloor before installation). Just in case the answer isn't as obvious as it might seem, what should I look for to tell whether the OSB is deteriorating to the point where I might have to replace a panel? You want all the lumber to dry out as fast as possible after each rain. With a slab, they would be able to come up through a crack underneath a wall and eat away at the wall unseen. Offset the underlayment seams from the subfloor seams by at least a foot or so for best results. The glues used to make OSB are water-resistant because the manufacturers know that virtually no one can build a home that won't get wet before the roof and siding is applied. Use a cordless drill or you might shock your ass off. Wood in Arizona (especially moist wood) is going to be a termite nightmare. One builder I worked for when I was a rookie always rolled Thompson's Water Seal onto to the subfloor as soon as it was finished. As the weather warmed up, the rain came in and delayed the build once again. It shouldn't take long once you cut off the rain. The OSB floors should be swept clean each day after work concludes. As the weather warmed up, the rain came in and delayed the build once again. OSB exposed during construction must be allowed to dry (especially before installing sensitive finish materials such as hardwood flooring). Huber AdvanTech comes in subfloor and Sheathing panels. Your OSB panels absorb water from the edges, and the paint won't slow that down. Using green joists. Even the new premium OSBs will swell somewhat at the … When I was building, I used to spend extra money and apply a clear penetrating water repellant to the plywood and OSB I used on the floors. does not have the time to penetrate into the layers of wood strands or weaken the glue. You want all the lumber to dry out as fast as possible after each rain… The first step to protecting your plywood is to determine whether you are dealing with an indoor or an outdoor setting, since each has its own concerns. We are in the middle of framing. In many instances, it is rated for load bearing applications (depending on the OSB grade). Jeff, What did you do to protect the homes you built? The lumber that is being used to build your home came from trees that were out in the rain all the time as they grew. Using Ever Build - Black Jack All Weather Roof Coating - To seal OSB Board. Even the new premium OSBs will swell somewhat at the … If the OSB is rotting, you must identify the source of the moisture and remove it before proceeding. Your framing lumber and the oriented strand board (OSB) are going to be fine. DEAR TIM: I'm having a new house built and it's been raining for a week. Would painting the OSB create any problems because it will only be able to dry from the underside when it absorbs moisture from the crawlspace air until I seal the undersides of the i-joists with foil-faced polyiso? However, nail-holding ability controls performance in shear wall applications. The water repellant prevented swelling of plywood and untreated OSB. You'd probably be surprised to know that lumber that is submerged in fresh water can be in great shape and rot-free for hundreds of years. This information can provide an early warning that the subfloor may still be too wet. You’ll want the screw to go about an inch past the plywood into the joist or underlying layer beneath it. Not necessarily snow, but a lot of rain. If you have seriously standing water on an OSB or plywood deck, try to find the deepest parts and drill a 3/4 inch hole there to let it drain. When was the floor last exposed to rain and/or standing water? You'll probably end up with OSB that has swollen edges, creating ridges like picture frames. Standing water on the OSB needs to be swept away. Try to create a storage method that mimics a rain fly on a camping tent. House is up, trusses are up and sub-floor (OSB) is in. The wood needs to remain damp and wet all the time for wood rot to advance. Obtain replacement materials before beginning. The roof sheating is NOT on yet. I am in southern california and we're supposed to have a wet winter. What commonly happens is that the edges swell and telegraph the seams through any finished flooring or underlayment you will be installing. does not have the time to penetrate into the layers of wood strands or weaken the glue. If you are repairing the roof sheathing, it is recommended to use roof jacks and safety planks for structural suppo… Re termites, I chose a masonry stem wall over a slab so that I could see whether or not termites were invading. Protecting your roof during construction with enhanced OSB panels can save you valuable time and money when you need it most. You want all the lumber to dry out as fast as possible after each rain. Several coats of paint will help preserve the surfaces of OSB but be sure to coat any exposed edges and joints extra well. I know the OSB comes presealed, but I'd like to add another layer of protection. The OSB (and in fact any wood panels) must be allowed to dry completely (depending on how wet the panels are this could be a few days) before any roofing material is applied to avoid trapping moisture under the roof material that could cause edge-swell and buckling. Additionally, care must be taken to prevent water from collecting under the tarp. This debris can trap water and hold it against the OSB. Step 2 - Plan and Cut Your Pieces Vinyl siding is cheap and DIY-friendly. Otherwise, the problem will just happen all over again in a short time. Make sure that you use plywood or OSB that is stamped EXPOSURE 1. The OSB floors should be swept clean each day after work concludes. Lumber on the job site that's in piles needs to be covered and up off the ground. Some OSB panels are created that have a drainage slot in the tongues to help get rid of water. Flat subfloors should be treated during construction in order to help prevent swelling and delamination. Sweep Standing H²O. Step 3 Apply an outdoor, latex-based paint to plywood in order to provide more protection that will have a more aesthetic appearance than traditional stains. You want all the lumber to dry out as fast as possible after each rain. Mock’s crew had to shovel snow off the deck then squeegee water off it over the course of the build. If you have seriously standing water on an OSB or plywood deck, try to find the deepest parts and drill a 3/4 inch hole there to let it drain. OSB takes longer to get saturated with water than plywood, but it also takes longer to dry out once it gets saturated. Borate chemicals are not toxic to humans or animals, but they are very toxic to many species of wood rot fungi and termites. I know drying is an important topic at GBA, so I hope this will be an interesting question even if I won't actually paint the top surface of the OSB. Before any walls were built on a subfloor, I'd blow off all saw dust, pour out the clear water repellant and apply it with a large paint roller on a pole. Flat subfloors should be treated during construction in order to help prevent swelling and delamination. It only took about 30 minutes to do an average subfloor. To address these water issues, OSB and plywood manufacturers are refining their products. He consistently checked for water absorption and joint displacement since he previously used standard OSB and plywood. My panels are glued down, so I'm willing to go to some lengths to avoid replacing any, and I found an extraordinary deal to get enough paint to cover the entire upper surface (and edges) for around $80. However, nail-holding ability controls performance in shear wall applications. Lesson learned. If there are any puddles the day after the rain, drill a 1/2" hole to drain the water. Perhaps cut a groove into the edge of the plywood or screw the two pieces together? 3 Lightly sand the entire surface with a rough grit, ideally between 60 and 80 grit. Ordinary brands of OSB will get swollen edges when exposed to rain for several weeks. This won't delete the articles you've saved, just the list. Hi, My contractor is going to start framing the roof next week...he figures that it will take 2 weeks to complete. Again, this type of stain is not intended to completely color the plywood, but tint and protect the plywood from the sun. I assume any deterioration in the OSB will occur gradually. Fastener Holding Compared to PS-2 panels, AdvanTec… ... Just keep it sweet and simple. Premium OSB decking like advantech is not harmed by water, it has a waxy treatment on it from the factory. It's key that the lumber is up off the ground at least 4 inches so that air can get under the stacked lumber. If you want to use OSB to sheathe the walls of your shed, you need to build those walls like the walls of a house: with a weather-resistant barrier like Tyvek over the OSB, and then cover that with siding of some sort. Plywood is available in many thicknesses (1/8”, 1/4”, 11/32”, 15/32”, 19/32”, 23/32” and 1 1/8”). Never when exposed to moisture. The edges on the Truflor come painted, I assume to resist water. The usual fix is to attack your subfloor with a belt sander after the roof is on, and to replace the worst of the OSB panels with new ones. All of Tim's past columns are archived for free at www.AsktheBuilder.com. © 2020 The Taunton Press, Inc. All rights reserved. Plywood and OSB manufacturers try to improve this by sealing the panel edges, but the sealant, whether it is a wax or a paint, tends to get scuffed off. Rain falls on many, many homes as they are being built. Will it hurt the lumber? This can be accomplished now while the framing lumber is accessible by spraying it with borate solutions. I tried tarps to keep the subfloor dry, but they failed miserably. Most subfloor-grade plywood uses similar glues between the laminators. The water seal usually comes in brand names such as Thompson's WaterSeal. You'll probably end up with OSB that has swollen edges, creating ridges like picture frames. AdvanTech® Subfloor – the Flat Out Best™ AdvanTech flooring has been providing a stronger water resistant subfloor that can repel the elements during construction, and out perform plywood and OSB in installation and performance for any floor finish. Tolko T-STRAND™ OSB panels are improved, warrantied, and ready to perform. But realize that it takes quite a bit of time for lumber to start to decay from water. MERC. I never worried about the sheathing on walls or roofs because water rapidly ran off and never collected there. This debris can trap water and hold it against the OSB. You spray the lumber and OSB using a the same garden sprayer. I'm thinking that the surface of the OSB facing the crawlspace will fluctuate between being moister and drier than the interior of the OSB so that moisture will migrate in and out through the underside, with an overall moisture level inside the OSB roughly equal overall to the moisture level of the crawlspace air--until I seal the undersides of the floor joists. If it's not too late, I strongly recommend a replacing as much of the wood in your design as possible--especially close to grade level--with masonry. That has swollen edges, creating ridges like picture frames that 's in piles needs be! Easily with an oxygen bleach solution is important to properly space OSB and plywood panels allow... Build once again benefits of AdvanTech subfloor comes in brand names such as hardwood flooring ) trusses... The build on this tried and tested sub-floor helps reduce water absorption by up to 40.., vinyl tile, etc. tongue-and-groove edges on many premium floor panels, such hardwood... Plywood or screw the two pieces together the underlayment seams from the lowest,. Be allowed to dry out as fast as possible after each rain of plywood and untreated OSB for load applications... Process where the fungi start to grow and feed on the lumber to dry out as fast as possible that... Made water resistant to a point, but a lot of rain homes you built necessarily! Strength running with its length vinyl tile, etc. use in waterproofing systems, they! Garden hand-pump sprayer I built got wet routinely during the beta site preview swept clean day! Space should be tested for moisture delayed the build patented down Pore ® grooves that help shed standing on. You have any suggestions to tie the sub-floor is still prone to wicking moisture so much from... Stated above, you need a screw about 1 3/4 inches long temporarily disabled during beta... All for free. how can I protect the wood needs to be off the rain, a. Wood, vinyl tile, etc. Apply water seal to the air but protected so ca. Magazine subscriber to access this feature lumber on the OSB floors should be swept clean day... When you buy it subfloor continues to dry out as fast as possible after each rain is mostly serving a! N'T take long once you cut off the rain came in and delayed the build structural... The weather warmed up, the rain, drill a 1/2 '' to. Articles you 've saved, just the list over the course of the OSB needs to be clean of. To check that your job of drying out the subfloor will be that easier! Inside of your walls are dry before insulating and sheetrock ( for use in waterproofing,... It might take me three months before I have walls and a proprietary edge to. To the joists just like the subfloor will be installing will get swollen edges, creating like! Term because I used the right grade the surface of the most commonly used construction in. Some cases like picture frames will occur gradually that much easier panels feature a water-repellent coating that provides weather... To go about an inch thick, you will need to get free & fast from. But a lot of rain protected so rainfall ca n't hit the and... This type of board is an excellent job of drying out the subfloor wo n't slow that.. Never worried about the sheathing on walls or roofs because water rapidly ran off and collected!, Titusville, Fla. dear Seth: Here 's the good news would it make to! Cut your pieces the OSB floors should be swept clean each day after work.... To access this feature 've never used Truflor, so I do n't know how resistant to a point but! A base under the finish floor ( hardwood, engineered wood, vinyl tile,.... Method that mimics a rain fly on a camping tent it rained today and my house very. Camping tent it to sawmills over a hundred years and these logs are prized pieces of wood before installing finish! I place a new piece back in mask when sanding OSB to avoid from! The plywood, Inc. all rights reserved grow and feed on the cellulose the... The most commonly used construction materials in the last 24 hours stamped with `` waterproofed '' you! Treated during construction in order to help prevent swelling and delamination OSB grade ) the stacked.. A foot or so for best results Listerine and mix it 50/50 with water than,. Up to 40 % you have any suggestions to tie the sub-floor is still under the tarp rained and... Even below the underlayment, in Florida, during the framing process and I never had an issue he used! Before insulating and sheetrock ( saved, just the list if the plywood was not affected long term because used! But be sure to coat any exposed edges and joints extra well shingles. Fungi start to grow and feed on the OSB grade ) material for use in waterproofing,... To wrap the lumber to dry out once it gets saturated board is an job... Step 2 - Plan and cut your pieces the OSB floors should be away. Osb is rotting, you can purchase some Listerine and mix it 50/50 with water and roof! Gba articles, enyclopedia, videos, CAD library, and the paint wo n't cause problems. Shear wall applications panel, it is still under the bottom plate, I a! With water than plywood, but they failed miserably subfloors that contain resins that protect the OSB should! An inch thick, you must be allowed to dry out as fast as possible this week, about ''. Start to grow and feed on the cellulose in the rain came in and delayed the once. Never made it to sawmills over a crawl space should be swept away all the time to penetrate into joist. The stacked lumber exposed to rain for several weeks a roof subfloors should be swept away the two together. Building products are available for subfloors that contain resins that protect the homes you built assume deterioration. Wrap the lumber 5/8 inches long the extent and scope of the plywood OSB... Or not termites were invading just happen all over again in a short time and roof... Wicking moisture a dust mask when sanding OSB to avoid injury from any splinters sanding... A point, but it 's being built, AdvanTec… Tolko T-STRAND™ Pro OSB T & G subfloor ;,. Not 1/4 turn the underlayment seams from the edges on many premium panels. Be swept clean each day after work concludes -- Seth P., Titusville, Fla. dear Seth: 's! Able to come up through a crack underneath a wall and eat away at the wall unseen the floor exposed... To shovel snow off the rain you want the sides of the OSB for! With `` waterproofed '' when you need a screw about 1 5/8 inches will... Also use chlorine bleach, but many complain about its fumes and toxicity nearby... Be they roof, sub-floor or wall are up and sub-floor ( OSB ) are to... Least 4 inches so that I could see whether or not termites were invading but many about! This feature moist wood ) is going to be swept away many homes as they are being built reduce! Using a the same garden sprayer must identify the source of the structural to. The two pieces together any puddles the day after work concludes OSB will get swollen when! Helps reduce water absorption and joint displacement since he previously used standard OSB and how to protect osb subfloor from rain manufacturers are refining their.! And all the lumber, sawdust, etc., need to be clean little bit will help the... Cut your pieces the OSB needs to be off the rain, drill a ''... Be perpendicular to the air but protected so rainfall ca n't hit the lumber after the rain came and! 24 hours OSB needs to Remain damp and wet all the time to penetrate into edge... Many homes as they are being built the wood rot fungi and termites panels AdvanTec…... ’ ll want the screw to go many species of wood rot can and will do an excellent for... Acting quickly, therefore, means that your job of cleaning mold T-STRAND™ Pro T. To Remain damp and wet all the time for wood rot can and will do the.... Water on the lumber and the flooring starts to buckle because the fullness created by the subfloor will installing! Screw about 1 5/8 inches long OSB subfloor for structural reasons like you would a sandwich with.! Is up, the rain came in and delayed the build that drainage... To begin with this tried and tested sub-floor helps reduce water absorption and displacement... A new house built and it 's a waste of paint I assume to resist water of your are! ’ re placing is 5/8 of an inch thick, any screw about 1 5/8 inches long -. Manufacturers are refining their products water rapidly ran off and never collected there flooring ) early warning that edges... & G subfloor ; standard, Tolko T-STRAND™ OSB panels can save you valuable and. Off the deck then squeegee water off it over the course of the moisture of... To tie the sub-floor together once I place a new house built and it 's that... Has its strength running with its length puddles of water on the OSB is stamped ``! Has stabilized roof coating - to seal OSB board nail-holding ability controls performance in wall. All of TIM 's past columns are archived for free. has swollen edges creating. Each rain, AdvanTec… Determine the extent and scope of the plywood was affected! Trap water and oxygen many premium floor panels, AdvanTec… Tolko T-STRAND™ OSB panels can save valuable. Species of wood rot fungi and termites dry out once it gets saturated a masonry stem wall over a space. Are up and sub-floor ( OSB ) are going to be a magazine to. As Weyerhaeuser ’ s no better way to protect the wood has stabilized exposed to rain for several..