Q&A / 

Wood Rot Repair Tips and Tricks

DEAR TIM: It seems like we’re constantly repairing things here at my home. The latest project involves numerous places on the inside and outside of our home where wood is rotting. My carpentry skills are better than my husband’s but that’s not saying much. Is there a way to repair wood rot without having to be a master carpenter? What are my options? What can I do to prevent wood rot in the first place? Amy S., Buffalo, NY

DEAR AMY: Wood rot seems to be a growing epidemic in homes. The complaints I’m receiving are growing by the month. Some of the rot can be traced to poor maintenance habits by homeowners, some to poor building practices by the trades, and believe it or not some traced to the lumber companies.

If you want to prevent wood rot, you need to keep it dry. Wood rot is simply different fungi that are consuming the wood. The fungi need water to live. You keep wood dry by keeping it painted and sealed. It's also a great idea to keep it above horizontal masonry or concrete surfaces by at least 2 inches. I prefer to keep wood up off of soil at least one foot and to keep air moving if possible to dry the wood.

Here’s some serious wood rot. It can be repaired without removing the wood in some cases. Photo Credit: Tim Carter

A year ago, I had to rebuild my front porch. I didn't build the house I currently live in. The builder installed a composite decking material without the proper spacing between the pieces of wood. The underside of the decking material was covered with fungi that was eating the wood particles in the composite lumber. Even composite lumber can succumb to wood rot!

Before you attempt to repair wood rot you need to stop the water problem. It's imperative that you hunt down and eliminate the water source that's causing the rot. If the wood has been placed too close to the soil, a sidewalk, a patio, a roof, etc., you may have to re-engineer the situation so the wood doesn't get wet, or if it gets wet it dries rapidly.

Once you have the water situation solved, then the wood needs to dry completely. This can take days, weeks or months depending on the season. Blowing air across the wood will accelerate the drying time. Be very careful about using a heat gun or other artificial heat source to dry the wood. Wood that's rotted and dry ignites very readily and can burn fiercely.

I've had great luck revitalizing rotted wood with chemical products that soak into the dry wood fibers. These liquids appear to be heavy bodied resins that adhere readily to the rotted wood. Drilling hole into the rotted wood can enhance deep penetration of the liquids.

These liquids, once dry, add considerable strength to the rotted wood fibers. Any gaps, holes, or voids can be filled with paste epoxies that adhere very well to the wood. The dry epoxy can be sanded and painted. You don't have to be a master carpenter to work with these DIY friendly epoxy products.

As with any repair products, you have to read all the instructions on the product labels. What you'll discover with most, or all, of the chemical and epoxy repair products is the wood needs to be dry. You want this anyway so the good wood doesn't rot further!

Preventing wood rot is not as hard as one might think, but it requires a mixture of common sense and best practices. Purchase lumber that has built-in rot resistance if possible. Redwood and cedar are exterior wood species that have natural chemicals that stave off wood rot except in the worst conditions.

Beware of hybridized lumber that's now grown by lumber companies if possible. This lumber has vast quantities of spring wood in it. Spring wood is the lighter-colored band of wood when you look at the end of a piece of lumber. It's softer and readily absorbs water.

Keeping wood painted and sealed is the most basic form of maintenance you can do. It's not the silver bullet, but it can help. Caulk cracks that allow water to penetrate into wood crevices.

If you want to give untreated lumber a chance to fight fungi, you can also treat it with borate chemicals. These borate powders readily dissolve in water. If you then soak the dry lumber with the borate solution so it soaks into the wood fibers, the borate chemicals stay behind after the water evaporates.

Fungi dislikes the borate chemicals and will not eat the wood. The only problem is the borates are water soluble. This means you can't leave the wood unprotected from repeated wet / dry episodes. If that happens, eventually the borate chemicals are leached from the wood and the fungi move in and begin to feast!

You can paint, stain or seal borate-treated lumber successfully once the wood dries thoroughly after it's treated.

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