Thank You. It is also a good idea to use a moisture meter after the three weeks just to make sure. Do these levels seen appropriate considering the recent rainfall. ie SW=Starting weight, TW=Target weight, using T%=Target percentage My calculation ( T% X SW = TW). I found your website at just the right time. Wood in buildings usually has a wood moisture content of 5% to 15%. Over a year ago, I re-shim all the piers with metal shims. Different wood? (He didnt cite a figure.) Substructures with WMC in this range may show decay or rot in floor joist, sills, and subflooring. Will the reading be accurate? A floor joist is a horizontal beam, usually made of wood, that is used to support and enclose the flooring above a foundation. Actually floors account for 15% of building heat loss depending on construction. 18 years ago the moist content (MC) of the beams and joist was 24% in an area of the crawl space that floods in spring. Example: 1.2mm Hickory wear layer 9mm thick plywood compose of 7 layers, 2 layers acacia, 4 layers of Eucalyptus\2 layers Acacia and one layer Poplar. This means your crawl space humidity goes up by about 22 degrees. I have some black walnut and cherry that Ive milled and want to make some charcuterie, cheese, bread boardsetc with, would the 6 8% dryness apply to this or what would you recommend? Im down to ~13-19% MC near floor level, based on a cheapo moisture meters readings. We also ship to other European countries, for dryer country like Spain the EMC could be between 12 and 14. Percent moisture content in wood is the ratio of the weight of water compared to the overall weight of a piece of wood. A good moisture content is between 6 9% for Colorado. Wood Moisture Content (WMC) is often used as an indicator of decay problems in houses. Hello and thanks for writing in. My meter tells me anything above 12% is wet but I cannot find any source of leaking or signs of water. You can determine the correct percent moisture content by using our free app called WoodH2O. could you please guide or on how much should be the Expected Humidity % in high Humid areas like UAE considering these are mostly for Indoor purpose where ACs are on 247 at say 24 Degrees. The thickness of flooring joists themselves will be determined by what's going on top of them. I am building a farm style dining table with pecan 2 thick X 8-0 long boards. Typical moisture content for furniture in a home is 6-9%. Yes, our moisture meters read MDF. Water Level Survey: Are You Smarter Than an Egyptian? Generally the entire floor is dry. board, and a 12-in. This building was constructed around 1966 and this little space appears very dry, in spite of a recent leak from an nearby hot water tank. Thank you for your very informative knowledge about all of the items on this page. The boards have dried nicely so far with minimal warpage or checking. Phil, what are you making with the cedar, and in what type of environment will it be? The acceptable moisture levels of wood and lumber are in the range of 6% to 8% for interior and 9% to 14% for exterior wood or for building envelope components within constructed assemblies. Like all wood materials, I-joists are susceptible to moisture. As the humidity increases, the MC increases, causing the wood to expand. After all, the wall is in contact with damp soil. ft., and averaging the results. Copyright - RLC Engineering, LLC. If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity. Hi Moisture Experts, My house is 25 years old located in Oregon City OR (near Portland). Furniture grade wood is typically dried to a target of 6%-9%. Hello Enjoyed the article. I installed a sump pump and 6 mil vapor barrier, but the barrier is not sealed around piers and the ground is moist under the barrier all year. Were looking to replace the floor in an old (unheated) hay barn with treated tongue & Groove 26 flooring and need to know if the advertised 19% MC will be ok and not shrink too much. That is still quite a wide range. Both slab-on-ground and suspended concrete floors for wet areas: are deemed impervious when steel trowel finished or polished. This pinless meter is accurate, Ive got 2 other pin moisture meters and all 3 of them read within only 1-3% difference as checked on wood structures. Chris. As it dries, you should expect slight changes in width and length. We found the problem and the leak was resolve quickly! What wood do you recommend that does not have a high oil/water content? They many times cite the need for further evaluations by what they call other so called experts. Why and how can I say this? One note is that we did have some fungus growth in our crawlspace during the construction phase prior to the crawlspace being sealed and had the contractor come and spray and clean the floor joists and subflooring where applicable. If a board reads 100% (Difficult to measure accurately) then the weight of the water equals the weight of that wood. The wood and varnish appear otherwise pristine, uncracked and not bubbled or clouded in any way. Mold and fungus in the crawl space can definitely become a problem, but dont be fooled into thinking that a Borate spray HAS to be applied in EVERY situation. The cedar I have is now at 12-16%. I had it milled into 2.25 slabs and I stacked it on a deck area. You can now understand the meaning of moisture content 5.5%, 15 g/m2/24 hours, and relative humidity 75% with these facts. The acceptable moisture content in wood depends on two factors: These two factors make it difficult to say anything specific about acceptable wood moisture content. Good moisture content for softwoods is 10% to 14% moisture. Screwed 2x4s parallel into the joists as added support. The fir windows and exterior doors will be affected by the the exterior and interior RH. I found your moisture levels column through a search for good wood for low humidity. Was told thats not done. This method uses the oven-dry method and then compares the results to those obtained using a moisture meter. Should I wait for the slabs to be within that 6-9% to cut and glue? However, many building materials may have been dried down to about 15% moisture content. The house was not in the flood area however they did receive 20 inches of rain. However, this range will vary slightly according to the geographic region because of varying RH levels. The floor (under carpet) had long-term water exposure supposedly from a shower in the adjacent bathroom (according to the plumber). Cracks in Concrete Slabs: Should I Be Concerned? Utilize the chart on following page to record the environmental readings at the time of installation. . The optimal humidity in a home is generally 35%-55% and anything under 20% is actually considered unhealthy, as it dries out the skin. This weight difference is then used to calculate the woods original moisture content. Writing all the way from Australia, Steven. at one spot, its 40%. 20% 28% Readings in this range indicate that conditions are border-line for decay. Please dont pay for a Borate spray unless the buyer wants to pay for it. In their warehouse, and perhaps partly also in the container. 24 and 26 framing studs should measure 19% moisture content or less. Wide-spread and often extensive moisture damage occurs in residences across the state of South Carolina and elsewhere in the Southeast due to the regions warm, humid climate. Or perhaps I should advise them to buy Wagner meters, for better accuracy ;-). i cored out a small section of the bottom beam (3 inches wide) all the way down to the foundation. Would you be able to say anything about the optimal MC range for this specific situation? It seems to me the supplier is drying the Teak to 14% because that is what is needed in Indonesia. Wood Handbook: Wood as an Engineering Material, https://research.cnr.ncsu.edu/blogs/wpe/files/2016/08/Equilibrium-Moisture-Content-of-Exterior-Wood-in-the-US.pdf, https://www.wagnermeters.com/shop/orion-950-smart/, http://www.csgnetwork.com/emctablecalc.html, https://www.spikevm.com/calculators/logging/equilibrium.php, https://www.wagnermeters.com/shop/orion-910-deep/, https://www.google.com/search?source=hp&ei=j6WRW76_NdmT0PEPkN29kAc&q=wood+moisture+content+and+mold&oq=moisture+content+and+mold&gs_l=psy-ab.1.0.0i22i30l3.8963.15970, Restoration Expert Says Moisture Management Critical to Health of Any House or Building, Correct Moisture Content: Critical to Your Woodworking Projects, Mckinleyville Middle Schoolers Learning about Wood Moisture Content, Ambient Data Loggers: Peace of Mind in a Box for Wood Flooring Installers, 5 Things Not to Do When Measuring Moisture in Wood Flooring, Alabama Wood Crafters Share Wood Woes When Overlooking a Moisture Meter. What are Acceptable Moisture Levels in Wood? This is expensive and its ridiculous. Since water conducts electricity and wood doesnt, the dryness of the wood can be determined by the amount of resistance to an electrical current. There are areas where organic growth was very active to cause deep, black discolorization. (864) 506-4701, South Carolina Residential Construction Standards, http://www.rlcengineering.com/wp-content/uploads/2019/04/RLC-Engineering-1.png. It is not fair to ask the seller of this home to pay some pest control firm to spray Borate on the floor system. Its mc is 11- 12% . within two percentage points of the EMC where the wood is going to be used. I have 1 1/2 thick cherry boards that I had milled from a tree in my yard last fall. 1. Under the floor. Back to top. Retain this information with your records. i also drilled into the wood every few inches, several inches deep with a typical drill bit. First time this has happened (splitting that is). However, a general rule of thumb is that the basement's humidity level is not over 30 - 50 percent. This is more likely to occur to occur in lower-grade boards, where knots and uneven grains are already present. Do you think that heated floor actually help to dry or do they make things worse and more humid! Be sure to acclimate the wood to desired EMC of the interior environment before you use it. 25-30 - Actual, and often extensive, damage is evident when readings reach this level. In fact, according to M. Steven Doggett, Ph.D. LEED AP, the founder of Built Environments, Inc., wood moisture content as high as 15% can cause corrosion of metal fasteners and at 16% may lead to fungal growth. But when you touch the pins to the embedded screws, you get between 14 and 24 % in various areas of the board. Please give us a call at (800) 634-9961 or email info@wagnermeters.com, if youd prefer. 78 0 obj <>stream Although, in this example, the moisture content of the timber rarely goes above 17%, it is not uncommon for winter moisture contents, in pitched roofs, to peak above 25%. I am based in The Netherlands. These are typical readings for exterior wood. Free Webinar The What, Why, and How of Wood Moisture Testing. This will drastically speed up the drying process. If the MC of plywood is above 20%, can it be redried in a kiln or would that harm the glue? Cheers, Howard Pruden in Edmonton, Alberta where its cold and dry. Softwoods typically have higher moisture content than hardwoods. Keep monitoring it. Currently the RH is 76%, the residence RH will be set at around 35%. Moisture was around 25% when milled, and the ends were sealed. Ideally, you want to check the EMC in the area you will be working on your slab, along with the area it will live in. 800-634-9961, or email sales@wagnermeters.com. Am i looking at mold if i dont rip the floor out? Production, storage, delivery and construction and in-use conditions that will prevent exposure to external or internal moisture or conditions that would allow the moisture content to exceed 18% at any time: Untreated Douglas fir: Framing in a low-risk building and meeting the requirements of B2/AS1 paragraph 3.2.2.2: Where there is a risk of . Leicester, NC 28748 I hope this helps. 28% and above Readings in this range are often accompanied by decay damage. %PDF-1.5 % Im trying to find specs on treated lumber for NC. I live in coastal South Carolina .we are definitely afraid of mold formation. board will move 3 times the amount as a 4-in. If any of these conditions occur, tell your installer right away. Do you have a suggestion? Good luck. The other thing to consider is examining how water is entering your crawl space. I have seen that 13.5% is high for furniture and you should aim below 12%. Lacquer will not make a reading difference as long as there are no metallic components in the lacquer itself. This is based on a chart in Wood Handbook: Wood as an Engineering Material. Building Performance Series No. The National Wood Flooring Association (NWFA) has a chart that indicates the moisture content of wood at any given combination of temperature and humidity. Check joints and bottom plates as moisture can get trapped here. The plumber said that the floor has an elevated moisture reading and took a photo showing the 99.9% (maximum reading) on the meter while the meter was on the floor. Two questions I need a reliable, easy to use meter that can cover all species as I now have a portable mill and that can be used for treated. We have had on/off rain and humidity 80-90% range. i used my dremel with a shaping bit about 1/8 in to cut vertical slits or vents about an inch deep and a couple of inches tall into the bottom 24 and have kept a commercial floor blower on the wood several hours a day for more than a week yet, the number is not going down. Thank you, In wood products manufacturing, 6-8% is pretty much the norm, at least in North America. This chart highlights the ideal levels of moisture in wood at various temperatures and relative humidity (RH) levels: In this chart, you can see a small highlighted section. I have been testing the bottom stud/sill board of an exterior wall on a slab of an old house that exposed in order to put a floor in. I built the tables in west Texas, but their final home is in Colorado. If humidity levels in the crawlspace with all these measures taken place is above 60% the joist and the subfloor will have a high MC reading. What is the acceptable moisture level for plywood? Because wood shrinks and warps as it dries, woodworkers want it to be pre-shrunk before they use it. Sagging or Uneven Floors Solutions. in other hardwood areas that wasnt close to the water, was measuring about 16-19%. Any suggestions to this being possible to correct? Longer pins with insulated shafts are designed for the purpose. If decay or WMC readings over 28% are present, find and fix the sources of liquid water quickly. Standard moisture contents for hardwoods are 6% 9% MC. Wood exposed to air with a RH of about 90% will reach a Wood Moisture Content of about 20%. Because of the different materials involved, they will react differently to high heat, thus giving you an un-even plywood surface. What should be the approximate Highest MC to prevent wood problems to include finishes? Condensation on the inside of a windowpane. Water was coming out of this outlet and onto the floor? To achieve this, Acceptable Solution E2/AS1 says that, on near-level sites, the floor level must be no less than 150 mm above the crown of the road or the lowest point of the boundary. The photo shows a floor that is out of level over four or so boards adjacent to the external wall. Accuaracy is of course more important.. Everyone who works with wood needs to understand how wood interacts with moisture in the environment. Alternatively, you could set up a crawl space dehumidifier and draw the . Be on the lookout for flooring failures such as swelling, buckling, cupping, etc. Notice that the EMC of the in-use location is the same as the MC: So, using this chart, we know that in an area of the country where the RH inside a home or office is anywhere from 26-32%, both the EMC of the in-use location and the wood moisture content kept in that location will be 6%. We dont know if we still should be having a commercial drying process? Its never constant. 2013-10-14 03:14:29. Thank you. provide a good substrate for a wide range of wet area finishes. Last reviewed: 12 Sep 2021 Last published: 12 Sep 2021. Learn how your comment data is processed. Divide that difference by the sum of the on-center spacing of the floor joists: 118.5" / 16" = 7.40625. Doesnt sound like this has been a problem in the past. this is an interesting read I landed upon as I was searching for MC in wood items. Floor joists come in dimensional lumber lengths from 8 to 16 feet or more. The cause that may produce this will be discussed in the section "Biodeteration of flood". So what do you think is the ideal moisture% I should dry them to before rotary polishing them? Your table may have been a little too high in moisture, hence the crack as it dried slightly in the drier environment. Thank you. Which do you recommend? Box 1437 The interior home conditions are, AC running at 68-70*F. Exterior wall condition 104*F as checked with an IR thermometer of East wall not in the sun. When I purchase it its soaking wet and Ive always given it a few weeks, stickered and covered for at least 2 weeks, sometimes up to a month, to get it down to around 17-19%. Moisture contents in wood floor joists in houses with moisture problems are exceeding the 20% maximum level for air dried lumber. Including some high-end species like Rosewood, ebony, Mahogany, White Cedar, Bija Sal, Walnut, Gmelina, etc. The acceptable moisture levels in basement walls and floors will depend on many factors. My builder and flooring contractor asked for me to give the hardwoods a season to acclimate and they would surely move back together in june/july time frame. i want to make a headboard from it. The same study showed a 40% loss in joint strength and concluded that a 20% MC may significantly compromise shear resistance of exterior walls. The purpose of acclimating is to allow the flooring to equalize to the surrounding conditions, no matter how large the room is. According to Dr. Eugene Wengert, professor and specialist in wood processing at the University of Wisconsin-Madisons Department of Forestry, wood should be dried to a water MC thats within two percentage points of the EMC where the wood is going to be used. We have had very bad cracking in sheetrock and floors. Yes, it is possible to have a moisture content reading of 99.9%. It was such a good read. The engineered wood floor appears ok. Would it still be 9% for pressure treated wood? Also, there is a risk of mold. Also, the glue manufacturer should ideally give you some specifications for max and min moisture content. I live in michigan (humid summer, long cold winter). Very educational! I have come across this and havent made the purchase from my friend because I am not sure about the warp or breaking it will come. Whats the Difference Between a Home Inspection and an Engineering Inspection? My question: what is the complete saturation reading of wood? I will get further testing from those not involved. I am shipping teakwood furniture from Indonesia to California. Stopping the moisture is much cheaper and easier than repairing the structure. With a degree in Computer Systems, Larry is involved in both hardware and software development of wood moisture measurement solutions. Therefore, just because the wood is kiln-dried doesnt mean it has lost the ability to absorb moisture. He added that plastic sheet ground covering that his company laid over my crawl space had been moved in spots and that I no longer had full coverage. hellow! Freshly cut wood has a lot of moisture in it. I buy many Artificial Trees for our Stores, which has Wood Stems/Barks, mainly produced in China & Shipped to UAE. I would not recommend re-drying finished plywood. During the summer months, when outdoor humidity is high, the hot/humid air enters the crawl space through the foundation vents and condenses on cool objects. The floor immediately felt stronger. Therefore, in order to avoid post-construction problems, a woodworker building a cabinet for this particular interior environment would need to dry his wood to a moisture content of 8- 9% beforehand and then keep it that dry during the construction process. Because ventilated crawl spaces throughout the Southeast United States allow high humidity and fungus spores to enter the enclosed space beneath the home. The more specific way to know would be to measure the relative humidity and temperature in your homes air and then plug the numbers into a calculator like this https://www.spikevm.com/calculators/logging/equilibrium.php This will tell you what the MC% should be based on your specific environment. we are getting hardwoods from our Uk Suppliers and accoya coming in at 2% and once we use the timber we are reading 0% we have tested the reader and its accurate even joinery grade sapele wood and Tulip wood coming in at 0% we cover these in 3 coats of sikkens paint and sometimes we get jobs where we are having to go back as our joinery is moving and we are guessing its because of these moisture levels and had never checked previously. The angle iron will prevent much warping, and I do plan on finishing all sides (and ends). Jerry, From a moisture standpoint, water in the basement can over time absorb into your subfloor. The SG setting is on the card that comes with the meter. Perhaps there is something different about the East and West walls. All houses now use perimeter foundation so outside contact temperature stays at about 55 F all year. Your subfloor moisture level should be no greater than seven to nine percent when you are installing flooring. You are correct, furniture grade hardwood is typically dried between 6 to 9%. The installer should then check the moisture content of multiple boards and average the results. The excess moisture source should be corrected if found. Any moisture content measured higher than that might result in movement, such as warping and twisting, once it dries. Next, check the moisture of new floorboards. Indoor humidity is around 50%, indoor temps around 70 degrees. To make sure the wood is properly dried, he always uses a moisture meter before working with it. Sorry, that time of year. My last Wagner was appropriated by the individual who appropriated other tools out of my old sho. Hi, in MN where extreme temperatures are very hard on homes. I get some water seepage through an exterior wall at basement floor level as a result of heavy rain. Yes, the wood can still be read for MC with a stain on it. Hope this helps. -25% moisture content in a VENTED crawl space. Your email address will not be published. I may have missed this already but I have a few quick questions. We will be having a deck built off my woodshop. My question for you is: after a smallish unheated underground space (similar to a basement, i.e. Because the moisture content of wood is equal to the weight of the water in the wood divided by the weight of the wood without the water, its possible for the moisture content to exceed 100%. A wood moisture content of 47% is too high. There is only so much moisture a piece of wood can give up, over time, before a failure occurs. At that point in time, we did not have a conditioned house. The acceptable wood moisture content normally ranges from 6% to 8% for woodworkers who build cabinets, fine furniture, musical instruments, dishes, toys, decorative art, boat restoration, or various other wood products. thanks so much in advance. These WMC readings are usually provided by pest control operators, and are included in the termite letter (form CL-100 Official South Carolina Wood Infestation Report). Meanwhile, the reference scale can be used to provide qualitative moisture assessments in other building materials. Your reading of 12.5% tells me it is workable. And would it be normal for the MC to vary from board-to-board and one end of a board to the other? Oiling the surface does not control the moisture in the wood. These are the "safest" conditions for most types of woodbetween 60 and 80 degrees Fahrenheit and 30% to 50% RH. Bird, who runs the School of Fine Woodworking outside Knoxville, Tennessee, says he knows wood shrinks seasonally but wants to minimize the shrinkage and expansion by drying the wood to a moisture content of about 8%. I removed an of the foam insulation. Soil is almost always damp. Should you check moisture levels on a trailor floor on a massive rainy day? Im still not sure that whatever they do will produce a good, long-term result, but I need to know what they should be doing to the wood. We have a free App called WoodH2O that will tell you the moisture content given certain temperature and humidity conditions. Poor Drainage: A Foundation Problem Waiting to Happen, A Trade Secret: Bucks Vinyl Siding Test, Foundation Repair Salesman: Licensed to Kill, Dear God, Martha, Our House is Breaking in Two!. Timber logs & Lumber into India company remained actively involved in harvesting and sale of Hardwood logs of Indian origin. . Avoid unnecessary moisture exposure of all wood components by enclosing the frame against adverse weather as soon as feasible. Is it possible to get a 99.9% moisture reading (using a Cassain GM-200 hydrometer) on a particle board floor which looks and feels completely dry? Good luck. Request Answer. 15% is too high, at least for hardwoods. if not, can you tell me why? Because ventilated crawl spaces throughout the Southeast United States allow high humidity and fungus spores to enter the enclosed space beneath the home. First, test the moisture level of the subfloor. Prior to the re-shim, the pier in the area that floods in the spring could be felt pushing up the floor, meaning the beam is warping and been monitoring it. A termite repair company (also licensed contractors) told me that I needed to replace the planks on my second story deck. As a result, the normal moisture meter reading for these materials in between 0.5% and 1%. Instead of addressing the plumbing and damaged wood, they installed a dehumidifier in 2015. My question is microwaving twice turned bowls what would be the general rule of thumb for a target by weight. I dialed the 800 number for Wagner meters and all I got was two sales pitches for a Life alert type device. They are now saying that they will replace whatever boards are bad and resand and finish the floors, however Im concerned that there is an underlying issue that will resurface here? It constantly absorbs and releases vapour into the . From a strictly static MC%, 16-20% MC for long duration is going to promote mold growth. The excess moisture source must be immediately corrected, and the situation carefully monitored until the WMC returns to the 12-16 range. The EMC of wood or lumber exposed to an outdoor atmosphere varies across the U.S. For instance, in the coastal city of Seattle, the EMC of wood or lumber is higher than the EMC of cities inland or in the Southwest. Though on occasion, they are made of 2x10s and tripled for additional . Here current humidity is 76%. You mentioned the humidity outside is 55%. Its hard to gauge anything off of a cheapo meter, but if and I mean if, we were to assume it was reading effectively, the numbers are too high. Moisture levels in your crawl space that go beyond 70% lead to mold growth and health concerns. We also have an Orion 950 moisture meter that will automatically give you EMC (Equilibrium Moisture Content) and other useful statistics. The normal moisture content of wood (or EMC) varies from 7%-19% depending on the RH in the air. Great info! For example, if the moisture content of the delivered wood is 12% and the optimal MC is 6%, then physical problems will occur during the acclimation process. The interior wood moisture level should be 12% or lower before painting. If the water leak was bad enough, dry rot can occur causing possible structural integrity issues. For wide-width solid flooring (3 or wider), there should be no more than a 2% difference in moisture content between properly acclimated wood flooring and subflooring materials. 1 4 I do not have a hygrometer or a moisture meter as I am a hobbyist. If you need further clarification http://www.nwfa.org is an excellent source. . If the wood is covered by a material like MDF or other, do we take 2x the measurements? Thanks Phil. Before installing plywood underlayment, ensure that the existing flooring is thoroughly vacuumed, free from debris, and stripped of wax. It gains or loses water moisture as the relative humidity (RH) of the surrounding air changes. 10 14% moisture content is too high. After reading your article and following comments, my question is : How much does the finish of a wood project for indoor use affect the moisture content? During my visit, I crawled to the four main corners of the crawl space and probed the floor system with an electronic moisture meter during this traverse. I recommend one of our Orion models: https://www.wagnermeters.com/moisture-meters/. The thinner veneers wont have much bearing on the reading. Replaced the subfloor, which is . Brilliant article. While oven-dry testing, if followed correctly, offers accurate results, there are a few drawbacks: These three drawbacks mean that oven-dry testing usually isnt the option of choice for hobbyists who work with wood.

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