Treating, preventing mold requires effort

By Tim Perryman

Recently the question of mold on the back side of exterior siding was raised. A home owner found a rusty brown substance dripping from between the planks of siding on the shady side of his home. Upon removal of the siding he found black and white mold on the siding, Which was unprimed --- bare wood. Only a one inch overlap on the top and bottom had been covered with primer. The homeowner was concerned: he wanted to know if the mold was dangerous, and if there was a way to inhibit the growth of mold in the future.

Black mold is becoming a serious problem in the Sacramento area, and all of northern California. Even the infamous Erin Brockovich supposedly had it inflict her home.

Chances are what the homeowner found isn't black mold, but its always better safe than sorry. He was advised to have it checked. There are companies that come out and take samples. The cost of approximately $700 seems steep, but it is a good investment in the piece of mind the homeowner gets when the test comes back negative.

The brown substance was probably tannins bleeding out of the wood, common in cedars and redwoods. It can usually be cleaned off with a mixture of water, bleach, and TSP.

Unfortunately, it is very common for exterior siding and trim to not be primed an all sides before it is installed. Priming adds to the cost of building a home, and since it's not something that can be seen, it is usually overlooked.

This can cause homeowners many problems. Even though the wood is not directly exposed, Moisture will still get in through the back and edges. Moisture will even try to escape from the interior of the home through the exterior siding. Homes are so well insulated these days, it's the only way moisture can escape.

The Sacramento area also has extreme weather conditions that go from cold and wet to hot and dry every season. This wreaks havoc on wood. When it gets wet, wood expands; then it shrinks when it dries, causing it to twist and warp, leaving the homeowner no alternative but replacement.

If the area gets constant moisture over a long time frame, the wood will most likely moldy and rotten. All it takes is for one mold spore to land on the surface, which is a perfect breeding ground.

Moisture and mold are two paint film destroyers, so even the best paint job will deteriorate over time under these conditions.

Prevention is the key. Professional recommendation is to look at the throughout the year to detect high moisture areas and alleviate those areas. Homeowners should keep an eye out for sprinklers that hit the house, especially.

If the siding on the home is not rotten or warped, and the mold has been tested and found not dangerous, the wood should not have to be replaced.

Mold should be cleaned with a bleach-water-TSP mixture and a scrub brush before painting. The area may need to be cleaned more than once. The mold will be killed , but will return if the source of the moister is not eliminated.

High grades of paint have mildew additives in them, or the additives can be purchased separately. This will battle the mold, but not under conditions of constant moisture.

This brings up the question of if and when to use caulking. When an area such as a window with wood trim around it, is completely caulked, there is little room for moisture to escape. This could cause wood to rot of all sides are not painted, especially in a high moisture area.

Caulking is the way to go if the wood is primed on the backside, including trim and siding. Caulking shouldn't be solely relied on to stop windows or other areas from leaking. Caulking will only act as a temporary patch.

Tim Perryman is the president of Perryman Painting, Inc., and the president of the Sacramento chapter of the Painting and Decorating Contractor's Association. He is a member of the Better Business Bureau and the NFIB. For more information, call (916) 344-6077 or go to www.perrymanpainting.com.