The Best Wood Siding Preservative

Basic Choices

• Preservative compounds for siding fall into three general categories: creosote, pentachlorophenol in oil, and water-borne salt treatments. Chromated copper arsenate, a water-borne salt treatment, is the most common wood treatment product used today. Only applied wood preservatives with salt are recommended for use around the home where people will come in contact with them -- such as walking barefoot on a deck. Ask if the product is eco-friendly, meaning it does not have a strong smell and it won’t hurt the environment.

Selective Additives

• Anything that coats wood to protect it from the elements is considered a preservative. Some preservatives have fungicides to protect the wood from mold and mildew. If you house is located near a lot of trees, you will want to consider a product with this benefit. Some wood preservatives contain compounds that are toxic to termites or other eating insects.

Oil Base Versus Water Base

• A wood preservative can be oil based or water based. Oil-based stains contain petroleum-based solvents that soak into the wood. A log home or house made of rough-hewn siding resists water and rot a lot longer with an oil-based stain. You may not have to reapply an oil-based stain for 10 years or longer, while water-based products may last only five or six years. If you use water-based stain, it will definitely repel water away from the wood. Working with a water-based product is easier because cleanup requires only soap and water.

Environmental Variables

• Take a look at your environmental issues in making a choice. Ultraviolet protection is more important if you live in a hot, dry climate. Sun damage is a greater threat than mold and mildew in this environment. Some woods, such as teak or redwood, are waterproof. Softer woods such as cedar or pine need waterproofing -- even in dry climates.