Can I use redwood instead of pressure treated lumber for my fenders?
I get asked this question a lot, short answer…Yes. But there’s a reason very few contractors use pressure-treated redwood (or pt) for mudguards and baseboards.
Let me first say that I have remodeled homes in the San Francisco and Marin areas that were over 100 years old – built entirely of redwood – and are still in great structural shape. That’s because redwood is naturally high in acids, which prevents rotting and keeps bugs from eating it, since those are the two worst enemies of the home, redwood makes sense. Until you look at the price tag. The fact is that many redwood areas have been logged, and those that haven’t are now protected. As a result, the cost of redwood is very high compared to other framing products, and they now use trees with younger growth, which equates to more knots, twists, and bleaching.
So to keep costs down Pressure treated wood was introduced as a wood that could mimic the attributes of redwood but at half the cost. The pressure treated lumber is usually Douglas fir or sometimes hem fir and injected with very toxic chemicals (copper or zinc napatan being the most powerful). These chemicals prevent rot and pest infestations, but are also known to cause cancer by contaminating groundwater when dumped in landfills. In California, pt residues must be disposed of in biohazardous waste landfills. Recently, the toxin levels have been lowered by approx. 50%
It is also worth noting that it is never acceptable to fasten untreated Douglas fir lumber in direct contact with concrete. There are several ways to treat your Douglas fir yourself and make it resistant to rot and pests. The #1 way to do this is to apply copper napatan either in a spray or a regular brush-on liquid. You can find this at almost any neighborhood hardware store, but be careful! It will smell bad for a day or two, so don’t apply directly to living areas. Be sure to read all factory directions regarding the application of any sealant or rot prevention product.
So to answer the question, yes…absolutely, redwood is a great product for mud skirting. But if you’re going to use redwood, save yourself some money and get “rough cut” lumber, it will be a little bigger so you’ll have to cut it to width, but the price difference is worth the extra work.
#redwood #pressure #treated #lumber #fenders