You will doubtlessly come across a wide range of literature online regarding the prevention of exterior wood rot. Certainly, rotting timber is a fact of life if you live in an old house or a wet climate. However, the best cure is always prevention and I will provide you with some tips to help prevent your exterior timber from rotting. Please note that you don't need to purchase expensive fibre cement, PVC or other products marketed as rot proof if you follow the advice below.
1 - Choose Rot Resistant Wood
This is an obvious tip, but one often neglected by homeowners. Tropical hardwoods such as Teak and Cumaru are excellent decking choices because of their extreme hardness and the fact they are exceedingly resistant to insect and rot damage. The problem is, they are expensive. More affordable options include Cypress and Western Red Cedar.
2 - Make Sure Surfaces are Sloped
No matter what you build, it must have the ability to shed water or rot is inevitable. This means building handrails and window sills at a slight slope. If it rains, the water must have somewhere to go rather than staying on your wood. For handrails, you can also design them with rounded tops so the water falls off.
3 - Prime Every Side
You must prime all six sides of the exterior timber once it has been installed or be punished by rot. This means using an oil-based primer on the back, front, both ends and both sides of the wood. An oil-based primer is the right choice because it penetrates the timber better than its water-based or latex counterparts. The result is increased resistance to water. Use two coats of the primer for extra protection.
4 - Let the Wood Dry Out
This means providing good airflow. This can be achieved by ensuring the timber isn't in direct contact with the ground, masonry or cement. If you can, design the project so that there are gaps between vertical and horizontal surfaces. Exterior wood will get wet, but good airflow significantly prolongs its lifespan.
5 - Plug the Fasteners
When you nail or fasten the timber, plugging the fasteners prevents the formation of divots in the wood which catch water and speed up the rotting process. Begin by pre-drilling a hole that's the size and width of the fastener plug and put the fastener in this hole. Add some wood glue in the hole and put the wooden plug into it. Use a mallet to pound the plug in place and sand the surface. Use window glazing putty to fill any gaps.
If you follow these tips for your next project, your exterior wood will last much longer. If you ignore this advice, the long-term cost could be severe.
