Designed to Decay
How to Keep Wood Homes Solid
There are many reasons why wood is such a great building material (see this blog for the list<https://home-partners.com/articles/wood-remains-popular-building-material>). Just about the only disadvantage to wood is the fact that it’s designed to decay. It’s a natural material, subject to the appetites of many tiny things that naturally chow down on cellulose.
Wood also breathes – it has pores, channels, occasional cracks and knots that let in moisture. With the moisture come various molds, fungi, and bacteria that break down the wood fibers, making it weak and providing even larger pathways for insects.
Sunlight plays a part in breaking down wood, too – or perhaps we should say two parts. The ultraviolet rays in direct sunlight weaken the surface of the wood, while the heating and cooling of the daily cycle causes expansion and contraction that leads to cracking and can also loosen fasteners. Yes, it ain’t easy being wood!
Careful Construction and a Proper Finish
Careful construction techniques and a proper finish are the best ways to keep any building looking young and pretty. They keep out moisture and block the sun’s rays. With a good start and regular maintenance, wood buildings can last hundreds of years. Let’s talk about that good start first.
- Keep the wood off the ground: There should be at least a six-inch gap between the bottom of the siding and the surface of the ground.
- Start at the bottom: Make sure the foundation is well sealed from footing to sill, including a sturdy vapor barrier beneath the floor. Good drainage around the footing is critical.
- Roof it right: There are specific recommendations about how to apply each type of roofing. Follow them to the letter. And make sure the drip edge and eave overhang are wide enough to keep falling water away from the siding.
- Ventilate the attic: If you have an unheated attic, it needs a properly sized vent in the gable or perhaps the roof. Soffit vents can increase the ventilation, but all vents need to be installed in a way that prevents the wind from blowing in moisture.
- Ventilate the roof: If your living space goes right up to the roof, there should be a vent area above the roof insulation, with soffit vents and a ridge vent to let the air flow through and carry away any moisture.
- Put up a barrier, inside and out: Moisture can seep into the wall from either direction, so a strong, solid vapor barrier should be installed between the exterior siding and the sheathing and between the inside of the studs and the back of the inner wall material. All seams in the barrier should be sealed with tape or caulk.
- Make the siding tight: clapboards, shingles, shiplap, paneling – there are many ways to finish the outside of a building. In every case, the overlap should be wide enough and tight enough to keep water out of the wall.
- Caulk like crazy: Whether it’s pelting rain or wafting vapors, moisture can seep through the narrowest cracks. Caulk everywhere the siding meets a piece of trim. With some siding types, you may need to caulk behind each joint as well.
- Seal the hatches, too: Windows, doors, vents, chimneys, electrical entrances, and every other hole in the wall and roof needs to be thoroughly caulked, inside and out. The outside trim around windows and doors will need flashing, too, particularly at the top, but sometimes the sides as well.
- Let in fresh air: With the house well sealed, you may need an air exchanger to bring in fresh air and remove excess moisture. This protects both the house and your health!
Sealing the Pores and Blocking the Sun
Finally, think about surface finish:
- Choose a paint or stain that will both seal the wood’s pores and block the sun’s ultraviolet rays. Even if you want a natural wood look outside, you should seal the surface with a clear finish that has UV blockers in its formula.
- Don’t expect the paint or stain to seal up anything more than pores. Caulk carefully! Use a clear caulk on natural finishes.
- Back stain your siding. This means putting at least one coat on all sides of the siding before it is installed. You can also touch paint onto the freshly cut ends of siding boards before they’re nailed up.
This extra care at the time of construction will increase the value, beauty, comfort, and lifetime of your house, business, or any other structure you need to build.