The challenge of utilizing wood starts with choosing the right wood. The best machining and excellence in workmanship cannot guarantee a high quality product if wood species, grade and moisture content are not suitable for the job. Everybody working with wood has his own unique way of creating masterpieces. Part of his skill is to understand wood. However, the right moisture content is a basic requirement.
Don’t waste time and money on wet wood.
Buying Wood: When ordering lumber specify expected moisture range. Different moisture levels are expected in furniture grade lumber, moldings or lumber lumber. Upon delivery, check the moisture content. Notify the supplier promptly, when the moisture content is not right. If you wait too long, the supplier may not accept any claims and put the blame on improper storage, while the wood was in your care.
Selecting a Wood Species: Not all wood species shrink the same. Check the Internet for the shrinkage factors of the woods you are working with. When mixing different wood species in the same project, select wood with the same shrinkage factors. Unfortunately, more shrinking is always accompanied by more warping. In entranceways, kitchens or bathrooms, it may be advisable to choose more stable floor planks of higher grade to avoid problems. One rule applies to all wood: The more parallel the grain runs to the edges of the board, the less cupping, crowning or warping can be expected.
See Shrinking, Warping…
Engineered Floors and Laminated Panels: Engineered wood products can be very stable and not sensitive to moisture changes. The performance of an engineered product depends on the shrinking tendencies of the top layer, while the multi-layered backing is dimensionally stable. Whenever the top layer shrinks too much and the backing does not follow, problems can occur. Depending on the structure, the engineered panel of floor planks may either cup or the top layer delaminates. The wider the floor planks, the more problematic the engineered planks could be.
See Testing of engineered products…
Proper Storage: The battle with moisture has not been won when the lumber is dry. Dry lumber should be stored in a closed-in area with a controlled climate, otherwise the dry wood will pick up moisture from the air, if stored in a damp place. Check relative humidity and temperature of the warehouse or other storage areas and compare to the moisture content of the wood. This will show if lumber will change its moisture content while in storage. If the EMC for relative humidity and temperature is the same as the moisture content of the wood, no changes will occur.
See EMC Table.
Proper Acclimation: Manufacturers of wood floors and the NWFA organization suggest allowing time for acclimation before installing a wood floor. Trim, ceiling panels, cabinets and other woodwork should also be allowed to acclimate before being installed. Proper acclimation only takes place when the room conditions are the same as afterwards, when the room is in use. A floor will not acclimate properly when the heat is off, the temperature drops and the humidity is higher than usual. > check out Lignomat’s new EMC data-logger BL2, which records RH,T,GPP,DP,EMC
Restoration: When restoring antiques or repairing furniture, new wood is added to existing woodwork. Make sure to match the moisture contents. Otherwise, shrinking, warping or delamination may occur as the wood equalizes.
Shipping and Moving Furniture: When furniture is moved from a damp shop to an air-conditioned office or from a dry climate zone within the US to a moist climate zone, surface checks may appear within days. Cabinet doors may suddenly not close due to uneven drying. Severe moisture defects can ruin furniture when moving to a new home. To minimize defects make sure that temperature and humidity are slowly adjusted.
Woodwork manufactured overseas will only arrive in good condition here, when the lumber was dried to US standards and packed properly.
Moisture Infiltration from Outside: Excess moisture from outside can come inside through open doors and windows, not properly sealed walls or leaks in the roof. A moisture problem may be noticed when the floor cups, but it could be hard to find out where the problem originated. It is not only bad when the floor cups, it is even worth when mold grows underneath the floor or behind the sheet rock. Moisture trapped anywhere inside a building will migrate into any water absorbing (hygroscopic) materials. If moisture problems appear “out of the blue”, do not start repairing the damage before the source of the problem has been found and eliminated and until all parts of the building have been dried out. Drying out should start immediately to avoid mold built-up. The source of the excess moisture has to be found.
Repair of Moisture Defects: For short moisture intrusion, the damage can be superficial and may disappear after the wood has dried out to its original moisture content. The cause could be seasonal changes. If a floor was not dry at the time of installation or absorbed moisture after installation, cupping or crowning will occur. In some cases the floor can be re-sanded and refinished, but only after is has been confirmed that the source of the problem is eliminated and the floor planks are dry now. If defects are so severe that permanent damage to the structure of the wood has occurred, there is no cure. Therefore, moisture problems have to be avoided before they occur.
See The challenge of Hardwood Floors.
Moisture Measuring and Record Keeping are worthwhile:
Determine the moisture content before you start a job, do not waste time and money on wet wood. Keeping records of your measurements will help when problems occur. Then, you can go back and check the moisture history of the lumber involved. And if nothing else try avoiding making the same mistake again.
For moisture related claims after floor or cabinet installations: In case of complaints the question always comes up, who is to blame. The problem may be very obvious, but the cause for the problem is often hard to find: The home owner turning the air-conditioning off, the cabinet maker or floor supplier delivering products with too much moisture, the installer making mistakes, the contractor not checking the concrete slab, drywall or wood moisture, etc. Taking moisture measurements and keeping records is important until the job is completed.
See Flooring Moisture Report.
For water damage restoration: To get paid for your work, you need records to show the extend of the damage and you need records to show that the problem is no longer there.
Every recorded moisture reading has to indicate the measured value, wood species setting, the moisture meter model, date and location, where the readings were taken.