Warping
Wood Warping and Shrinkage
Anything made from wood has a degree of flexibility to it that is often brought out or enhanced by the presence of moisture. Humid weather, flooding, or being placed beneath a leak can cause wood to warp. Warping means the wood dries unevenly, curves at an angle, and no longer lays flat.
There are several different types of wood warping, depending on the area where it is most warped. Wood shrinks in three directions - along the length, across the face (the flat surface of either side), and on the edges. Knowing this, you must realize that anything wooden left outside in the rain, or during a flood, or even a particularly humid day, is at risk of permanent damage.
The Effects of Moisture on Wood Products
Let's say, for the sake of argument, that you've recently purchased a house number sign made of plain timber. It's a beautiful house number sign, and you hang it up on a tree outside and feel proud of yourself for your purchase. During the night, a storm soaks your new house number sign, and when you wake up you realize it's still wet.
Over the next several days, as it dries, you'll notice the house number sign will begin to change shape. This is due to water slowly evaporating out of the house number sign and its unfinished timber material. It may crack or split, or bend into an unuseable shape.
A house number plaque in a metal frame is not protected from warping. In fact, it could break the frame or warp right out of it if there is sufficient moisture. A metal frame may provide an aesthetically pleasing appearance, but it will not do anything to stop warping in an unfinished timber house number sign.
Now, let's say you return to the store and purchase a finished timber house number sign. You hang this house number sign in front of your home, and again, a terrible storm occurs that very night. When you wake up, your house number sign will have weathered the storm just fine, because it's protected from the elements by a thick layer of varnish.
Protected From Moisture
Marine varnish, used on yachts and pleasure boats, is typically used in house sign finishing because it preserves and enhances the beauty of the sign itself while simultaneously protecting it from excess moisture. Most finished timber products are sealed in some manner, depending on the conditions they're expected to encounter. Construction grade timber is sealed using chemicals to repel insects and moisture; timber furniture and home goods are finished to give their surfaces an attractive shine and guard them against scratches and dings.
When you purchase a home sign, be sure to ask if the product is sealed against moisture. If not, you might be able to save money by applying the varnish yourself.