Common Causes for Failure of Interior Wood Wall Paneling
Reclaimed Lumber Products pioneered the accent feature wall paneling with their authentic thin cladding boards or reclaimed barn planks. Building on this many years of experience here are some tips to get the best application and installation for your wood walls and ceilings.
The leading cause of failure is due to a change in moisture content at some point after the installation. All of our material is kiln dried and heat sterilized to a targeted moisture content of at or below 8%. (There is a very strong chance that our material is dryer than your moisture content in your location).
With an average change in moisture content between different seasons or climates a moisture content change of about 4% could change the width of one of our paneling planks by up to 1/16". There are factors that can change this such as width of the board, grain patterns in the wood, temperature and relative humidity. The point is, though, that without any major problems such as direct moisture one can still get enough wood movement to cause a problem just with normal differences in ambient moisture.
Even wood that has been acclimated and installed for multiple years can change in moisture content between different seasons. Indoor installations for wood tend to shrink in the winter because of the heating and expand in the summer.
Reclaimed Lumber Products uses actual reclaimed wood to make their wall paneling. We control the manufacturing process from start to finish. As a sign of quality we kiln dry our materials down to 6-8% moisture content during the millwork process. Our paneling may sit around for a while before being shipped to you, though, and might gradually raise to about 10%. Climate here in Idaho is dryer than average with an average equilibrium moisture content 3% lower than a number of climates on the east coast and in the south. For example this article has very useful information on how to calculate moisture content and has a table of different locations around the US: Forest Service Research Paper on Equilibrium Moisture Content (EMC) http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf .
How can you tell if your wood changed in moisture content after you installed it? If the wood starts to buckle like in the attached pictures it is likely gaining moisture. The boards are growing wider. There is no place for the wood to go and it pulls itself off the wall, bends, bows, and buckles because there is no room for it to stay flat in that row. If the boards develop cracks or gaps between the rows than the material is likely shrinking and drying out. This is not as much of a problem as the bowing and popping off the wall. If the boards were glued and fastened well to the wall it will probably be fine. Especially important is that you follow our recommend installation instructions which include some of the best practices below to anticipate these issues.
We cannot warranty natural wood movement. This is a solid wood product. If it changes in size it is because site conditions are different moisture content than the wood was shipped. A major feature of our product is that it is real wood and not a faux creation. Our process in making the paneling is coming up with a dimensionally accurate and defected former barn board that you can add texture and color to you wall. It is not meant for structural, flooring or exterior applications. Since we are not finishing, gluing or engineering it any fashion it will maintain characteristics of natural solid wood, so it can move with changes in the surround environment.
Here are our recommended best practices to prevent problems with installing solid wood paneling.
-Acclimate materials prior to installing; this means that you need to let the new wood reach the equilibrium moisture content of the surrounding environment. Bring the product into the environment that will be its permanent home. Do not bring it into the building until the building is conditioned and done with all sheetrock and painting work. You do not want to introduce extra moisture into the wood. Do not set the boxes onto concrete. The boards will not acclimate if you leave them tight stacked inside the boxes. They need to be taken out with airflow around them. More time is better for acclimation such as a minimum of a month. This is not a guarantee that the wood will not continue to change in moisture content but it will at least get the wood closer to the current moisture in your building. If you would like to have a more informed decision you should check the moisture content with a electronic moisture meter (we prefer the pinless Wagner moisture meter); then compare it to some other seasoned wood that is dry and been in the building for a long time.
-Ideally your wall color is natural wood color like plywood is or if it is white then you should paint it black. This will make cracks and holes less obvious.
-The paneling is random length meant to be installed over a sound and solid substrate preferably OSB or plywood. We regularly get asked if it is acceptable to install over sheetrock. Yes a number of people do it, but it is not ideal or recommended. We have noticed almost all failures or problems with installations have been over sheetrock. It does not hold nails or glue as well. It is much harder to fix a problem or mend an area if the installation was over sheetrock.
-Glue up the individual pieces with PL brand polyurethane construction adhesive. This glue works much better than caulking and the lower cost options in tube glues. Brad nails are helpful but not essential for every board in the installation. They are mostly used as a convenience for starter rows. You will find the that polyurethane glue has so much tack that you don't even need to use nails. Once the adhesive cures it is stronger than the nails or wood itself. This glue joint will not fail or separate on itself. We have seen glue joints fail when the customer just used caulking. Also glue over sheetrock fails and the paper pulls off. The glue sticks and holds better to the plywood. When one has a problem or needs to use the nails the plywood holds nails a lot better than the sheetrock. Treat the pieces like color and texture added to the wall. The substrate will give them strength. The planks themselves do not necessarily need to be perfectly structurally sound. For example if there is a crack in the board that weakens the piece, then just glue the whole piece to the wall. Once it is glued in place the crack will not matter.
-Putting a sealer or finish on the raw wood will minimize chances for it to absorb moisture or change quickly due to seasonal changes. We always recommend a finish for this reason and to make the material easier to clean. Most of our customers, though, prefer the raw natural look of the material like we make it. It is up to you if you want to finish it because ultimately you will determine how you want it to look and must live with the results. The sealer will change the look of the wood. Once one decides to put a finish on the material there are millions of options and combinations of stains that change the color and clear coats which might enhance the color or adjust the sheen. If one wants the least change use a low sheen like matte and water based finish such as a polyacrylic. Oil based finish will tend to darken along with enhancing and more amber effects on the coloring.
-Do not install in locations that will have unusual swings in moisture content. For example we have seen extreme drying beyond normal when there were dehumidifiers in the building. A more common problem is trouble spots like bathrooms with steam. There have even been problems in commercial locations like behind a coffee bar. Never install where direct moisture or water will hit the wood. Preventive measures for problem locations would be to preseal all edges and both faces before installing and to adequately ventilate the rooms.
-Do not install the thin wood paneling outdoors. The environment is too hard to control in that application, and the thin material responds quickly to changes in temperature and relative humidity swings. We can provide the same look and type of material in a thicker product that will be more structurally sound and stable for an exterior application. The thinner product is better for interior application because it is lightweight, easy to go around trim and electrical, more suited to be glued up, has a better yield and tight fit from the square edges, and installed over a substrate quickly. Thicker boards for exterior projects will be nailed, not fitted as tight, supplied with a lap joint, and most likely will be expected to move more.
Don't be afraid to install a new feature wall. The installation process is actually very easy and rewarding. The results will amaze you, but just use this extra care to make sure that your results will stay beautiful for a long time. We take pride in the quality of our materials with the extra care that we put into the millwork process, so we want you to be informed and take steps on your end to insure the best outcome.