When particleboard gets wet, it can swell or even disintegrate. The water will do no damage to the wood wall studs and floor joists unless they are in constant contact with the water for long periods of time. Plywood, will most likely warp and delaminate. The wood strands are precisely cut and oriented in order to produce a wood panel with uniform strength and density. October 5, 2020 by Curtis Lumber & Plywood. Having wet sheathing covered with tarpaper or membrane will trap the water in the sheathing - very bad practice and contrary to industry standardss for roofing. After it has dried out you may find that the plywood has delaminated, and may need a piece of it replaced. Wait it out. Although there are several ways that water leaching can be problematic, the degradation of the plywood’s flame-retardant properties is the biggest concern. This can be a real headache when one intends to install windows or doors with pre-manufactured liners. Some types of fire-retardant plywood can indeed get wet. These tests are quite rigorous, and the wood must not only resist ignition but also actively slow the fire’s spread in order to pass. Complete the form below and each week you'll get: Unsubscribe at any time. The water can ignite an explosive growth of mold on the wood surfaces, but this can be cleaned off once the house is under roof and the threat of water contact is minimized. Fire-retardant wood must be stored in a place where it will not be exposed to water or moisture. The plywood then goes through these steps to become fire-retardant again: This wood is placed inside a special retort chamber that can create the pressure necessary to infuse the wood with fire-retardant chemicals. The risk of warping increases and the rate of moisture evaporation decreases if damp plywood is left untreated. Are the wood walls, flooring and subfloor ruined? If it is spongy, then perhaps it will need to be replaced. The glues used to bond layers of wood in exterior-grade plywood and the strands of wood in exterior-grade oriented strand board (OSB) are made to resist water. ... they are only using plywood as they had the issue in a new construction project and the price of remediation and the stigma of “mold” put on the house cost them a lot more than the difference in price between the two materials. If the surface underneath is wet, mold and mildew may form, leading to the disintegration of the subsurface and the roofing felt. Below is a closer look at the most important considerations. Different products will require different treatment times and pressure levels, taking into consideration factors such as thickness and wood type. This means that the glues used to bond the wood plys, or the wood strands, to each other is 100 percent waterproof. Depends on the wood form and treatment or finishing done on the wood. This happens more quickly with thinner plywood; thicker sheets are more stable, because there's less flex in them. The wood is made from sawdust or wood chips and glue. When moisture becomes trapped in a subfloor, it can cause tiles to bubble and warp. This is very useful in building fires when every second counts. If The Plywood Was Pressure Treated Please see "Proper Handling" below for tips on preventing swelling. Since the work stoppage the house has experienced six major rains. Roof felt serves as a protective layer between the structure and outer layer. A. Shingle roofs are installed every day over wood decking that has been wet by rain. Thanks Richard Sparks. OSB that does get wet will tend to swell and delaminate first at the edges of the boards. Another issue is the potential for polluting nearby soil and groundwater with chemicals. Sorry.., Cutie Pie :(Hopefully it is only the plywood that is rotted and not the floor joist as well. Once the moisture content of the lumber is down near 12 percent, see how the subfloor feels to walk on. What happens if fire-retardant plywood gets wet? What happens to wood when it gets wet? Wood rot can and will start when the moisture content of the wood reaches 20 percent. This is one reason I like sheathing my houses with a base course of PT Plywood 2" around the bottom course of sheathing then going up from there with OSB (or plywood if the budget can take it). OSB's other moisture challenge has to do with dimensional stability - in other words, OSB can irreversibly swell, especially at the edges, when it gets too wet. 2. We respect your email privacy. This is also on a wall behind our water expansion tank. It will take several weeks to a month to fully dry. Immediately after the subfloor was installed, he framed the walls. We took the drywall and insulation off about 2 feet from the floor and found that the plywood was wet as well. Then work stopped and he has not done anything since. Second, and more importantly, it stops chemicals from leaching out of the wood upon exposure to water. Condensation occurs when hot, moist air hits cold, dry air. What happens to this type of plywood if it does get wet depends on a few factors. This will prevent mold from growing. Generally, no matter what type of material the carpeting is made from, do not install it in wet or even semi-wet areas. If it fails even one of the quality checks, the batch will not be approved. Condensation is more common in bathrooms and kitchens, where steam is produced by bathing or cooking.Homes are prone to problems with condensation during the colder m… This meeting causes water droplets to form on the cold surfaces (like your walls). The tear-off gets a lot more complicated if you have something other than asphalt up there: If you can see original wood shingles on the underside of your roof when you’re up in the attic, you’ll need not only to tear everything off, but also to install new plywood decking, all of which likely adds $5,000 or more to your costs. Obviously in Houston if we are lucky enough get rain there are a lot of frames that get wet. First by absorbing the water, then releasing it. You should remove the rotted plywood to see if there is more damage. Choosing the best plywood for wet area applications Maxiply MAXI Plywood clears the common misconception that marine plywood is the ‘only’ plywood capable of withstanding exposure to moisture. Once it "poofs" out it's time to replace it. Some varieties will be given a special treatment to control dampness, which can offer dual protection. They can also be painted and stained. Will the oak flooring be fine over the OSB? But, if it gets wet for a long period of time it can swell and lose shape, and, eventually, lead to the layers of wood splitting apart. What Happens To Wet Fire Retardant Plywood? But ninety-five percent of all exterior plywood and oriented strand board (OSB), that carries the American Plywood Association (APA) trademark, comes from the factories with a durability classification of Exposure 1. Overflowing toilets, bathtubs and sinks in bathrooms can cause water to seep underneath tiles and saturate the subfloor. Both plywood and its constructed wood brother, oriented strandboard, suffer from degraded structural performance and fungal infestation when they are exposed to overly wet conditions. Trapped water will boil when the sun heats the roof and the shingles will then have small pits … This is very useful in building fires when every second counts. Moist conditions causes plywood to soften and bend. Particleboard is a composite wood that is used to construct furniture, door cores, floors and cabinets. Fire-retardant wood can be a true lifesaver in the event of a building fire. Here are the four main ways you get wet framing lumber to dry: 1. In such cases, the exact thickness of the walls can complicate final finishing work. In addition, these products are dried in a kiln after treatment to guarantee their workable moisture levels. Fire-retardant wood can be a true lifesaver in the event of a building fire. Damage to the edge of the plywood allows moisture to penetrate into the layers, and can cause separations. Below is a closer look at the most important considerations. 5. Same for wet MDF. But put fans on it, and under the area in the basement too. Subscribe to the FREE Ask the Builder newsletter to receive professional advice for your home. Fire-retardant plywood that is labeled for interior use, on the other hand, must always stay dry and is shipped in enclosed trailers or wrapped and sealed to ensure its properties will not be compromised by moisture. I had a framer save a bunch … If its a panel product such as plywood, mdf or particleboard, most often than not, it would absorb water or moisture and expand a little. It happens quite often. What happens to this type of plywood if it does get wet depends on a few factors. The water will do no damage to the wood wall studs and floor joists unless they are in constant contact with the water for long periods of time. This is not a decay issue, but swelling can cause other difficulties in construction. The vacuum created within provides the appropriate conditions for the flame-retardant chemicals to be added. Six weeks ago my builder put in the floor joists and the wood subfloor. It is important to keep in mind that even leach-resistant fire-retardant plywood should not be placed into direct contact with ground soil. The builder needs to get the roof on as soon as possible and then let the house air out. For example, Exterior Fire-X products are made for use outdoors. Bill, the foil back plywood is all I've used for 12-15 years. Like plywood, it is widely suitable for use as a structural board, and is commonly used in roof and wall sheathing, in subfloors, and increasingly in furniture manufacturing. DEAR RICHARD: I am at a little disadvantage since I can't see the wood. What causes condensation? To understand why this is important, it is helpful to have some background knowledge of the process used to create it. Treated using fire-retardant chemicals, this type of wood can resist ignition and slow the spread of a fire. The idiot builder forgot to order the roof trusses. Like most types of wood, even if it is treated against water damage, extended exposure to moisture will start to wear and damage the wood. The danger with wet plywood is that is will warp and delaminate (the layers come apart, mainly due to the sheet being bent). My husband and I bought a home a little over 3 months ago and have discovered moisture inside one of our closets which has started mold growth (on an east facing outer wall that gets sun until about 1-2pm). The experts at Curtis Lumber & Plywood have the skill and experience necessary to select the right wood for every project and ensure it is properly treated and stored. If carpeting in a basement is absolutely needed, it should be elevated off the slab floor by using a raised subfloor of sleepers and plywood, or DRIcore panels. Call us at (703) 972-1947 or contact us online today to get started. Samples are tested for fire-retardant concentrations and burn rates, along with the depth of charring produced under specific burn conditions. Charring helps protect the wood from further damage in a fire, helping it to retain some of its structural integrity. Use Fans 3. Treated using fire-retardant chemicals, this type of wood can resist ignition and slow the spread of a fire. It is this infusion that sets this type of plywood apart from types that have only been given a surface treatment of fire-retardant chemicals; only the fully infused varieties meet fire code standards and many manufacturers’ quality control systems. Even in dry weather, soil can possess a significant amount of moisture which can degrade the fire-retardant chemicals in the plywood and even the wood itself over time. But wood rot is a slow process where the fungi start to grow and feed on … Most varieties of plywood will shrug off rudimentary water damage, and stronger varieties are better equipped to manage extended water damage. I'm getting oak flooring installed over this junk wood. The actual solid lumber used by many builders for walls, floor joists and roof … This type of wood begins as traditional wood or plywood that is dried thoroughly in a kiln. But it is not a common practice to build with treated lumber for the few times wood might get wet as a house is built. This may give people inside a building extra time to get outside safely. DEAR TIM: I'm having a new house built. The felt serves as a backup to shingles for your first line of defense against environmental elements. The water can ignite an explosive growth of mold on the wood surfaces, but this can be cleaned off once the house is under roof and the threat of water contact is minimized. My houses are somewhat large, and it is not uncommon for the plywood to get rained on since it takes 4-5 days to deck them, they sit for 2-3 days before roofer can get on the job, throw in a weekend, there is a good chance they will be rained on. It is a good idea to sand the OSB to get it fairly smooth before the finished flooring is installed. First, it stops the wood from warping and swelling too much when it is exposed to moisture. If you want to ensure that your construction project will offer maximum safety in the event of a fire, consider hiring a company that specializes in fire-retardant plywood. While the glue is waterproof, the wooden layers aren't, and they can swell or deform when exposed to moisture. Although plywood is usually more expensive than OSB, plywood is more resistant to moisture damage. Even if the plywood is rated as exterior-grade and manufactured with water-proof glue, if water penetrates between layers, it causes them to swell and warp, pulling the layers apart. In order for it to retain its fire-retardant properties, this type of plywood generally needs to stay dry. In fact, most are waterproof. Products carrying the Exposure 1 stamp are designed so that minimal damage will occur during normal construction activity. This often happens when plywood is stored outside for short periods of time before a project begins. A: It is never a good idea to install a roof over wet plywood or any type of roof sheathing. Fire-retardant wood must be stored in a place where it will not be exposed to water or moisture. Use a dehumidifier 4. Sign up to my newsletter to receive expert advice for your home! If not it easy to replace the rotted plywood. Use heat Wet lumber will naturally dry out if given enough time. It is possible to build with waterproof lumber and this is often done in the Southeast to prevent termite damage. What happens if plywood gets wet? It helps protect against water entering the building. They are tested for endurance to moisture and heat in addition to the standard fire-retardant properties using testing that simulates prolonged exposure to the moisture and heat they would see on a finished structure. In order for it to […] To ensure the plywood has been fully infused and will offer the expected benefits, the wood is then subjected to a series of quality control tests. But this takes quite a lot of moisture over a … This kind of moisture is what you’ll find on the bathroom walls after a super-hot shower. They let wet carpet etc dry on its own and never did repair the leak that caused the rot. The plywood is much more forgiving with moisture. Over time, trapped moisture can cause the subfloor to … Manufacturers use particleboard because it is less expensive than plywood. Water-repellent preservatives can also be applied to this type of wood for applications that will give it direct exposure to water and moisture. The builder said he will sand the oriented strand board (OSB) down to make it even again. Stacks of OSB plywood sheets. The OSB panels can feel rough and still maintain all of their structural integrity. What happens if fire-retardant plywood gets wet? Once the chamber has been filled with flame-retardant chemicals, the pressure is used to ensure the chemicals are fully and evenly infused into the wood. After the untreated wood has been placed inside the retort, it is closed tightly and all the air is removed. The water repellant prevented swelling of plywood and untreated OSB. The chemicals used for treating fire-retardant wood labeled as “Exterior” are made to stand up to weather conditions such as rain and moisture. But there are highly treated plywood also available built to be waterproof which should resist changes on contact with water. 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