You live in an old house? Good! Then you have rotted wood and know the frustration and worries it can cause. When a tree is still alive, water is its best friend, but after we turn that tree into lumber, water is the last thing it needs.
There are lots of products on the market today to patch wood. I listed some of my absolute favorites in this post here:
But if you are in need of a serious rotted wood repair, then you need a serious product and a structural epoxy is the just what the old house doctor ordered.
Unlike wood filler, structural epoxies don’t just cover up cosmetic issues in wood. They can replace whole sections structural wood elements. So, rather than having to remove some damaged piece of the house, you can simply fill in the damaged portion and move on.
My favorite structural epoxy is Abatron LiquidWood & WoodEpox. This system uses a combination of wood consolidant (LiquidWood) used to strengthen and rejuvenate weak, rotted wood and a filler (WoodEpox) used to fill in missing sections of wood.
Here’s how to work with it:
Step #1 Remove the Damaged Wood
The first thing you need to do is assess the extent of the damage. You’ll need to dig out the severely damaged wood. I prefer to remove any wood that is mushy or weak enough to dig out with a screwdriver. LiquidWood can be used on extremely weak wood to strengthen it and bring it back to life so not all of the rotted wood needs to come out, but anything that is falling out on its own should be removed. Vacuum out the remaining debris and dust so you have a clean area to work with.
If the wood is still wet, it will need to dry out before you begin your repair. Cover it in plastic if you anticipate rain and make sure the sprinklers aren’t the cause of the rot while you’re at it.
Step #2 Prep & Protect
These are some serious compounds you are about to use and once they are in place it is very difficult to remove them (that’s the whole point isn’t it!) Anyway, you’ll want to mask off the work area with plastic and painter’s tape to prevent spills and drips.
Be sure to wear eye protection and nitrile or plastic gloves while handling any of these products. This stuff isn’t like shea butter for your hands. If it gets on your hands, think Chevy Chase in Christmas Vacation with the tree sap episode. Don’t touch without protection.
Have a container of acetone on hand which is the recommended cleaner and solvent for these products.
Step #3 Apply LiquidWood
Once everything is dry, it’s time to mix up your epoxy consolidant. LiquidWood is a two part mixture. Part A (resin) and Part B (hardener). These two should be mixed together in a disposable container like a dixie cup or similar in equal parts. (<—Very important!) Mix them thoroughly, or you will have lackluster results.
Let them sit aside for a few minutes to setup. After about 5 minutes, apply the mixture liberally with a disposable chip brush. Once mixed, LiquidWood and WoodEpox both have a working life of about 20-40 minutes depending on weather conditions (shorter working life on hot days, longer on cold days). Don’t get too busy and forget about your mixture!
Depending on the condition of the wood it may need more or less of the consolidant. Apply until the surface is soaked and let it soak in for about 10 minutes before moving to the next step.
Step #4 Apply WoodEpox
WoodEpox comes in two parts (a hardener and a filler) just like the LiquidWood. You’ll need equal parts of both and then blend them together until you have a uniform color. One is white and the other a tan color. If you see any streaks of color in your mixture, you need to keep mixing.
Once everything is well blended, it’s time to start pressing it into place. Press the mixture firmly into place to fill the missing areas. Press it deeply into the gap to make sure you fill any air holes and have a solid repair. The other important thing to remember is to leave enough epoxy proud of the surface so that when it is ready to sand, you have a smooth, well-blended repair. If you use too little, you won’t have a level surface to sand down to.
Step #5 Sand, Prime & Paint
The epoxy will begin hardening immediately and depending on the size of your repair, it will be ready to sand in anywhere from a few hours to a day. Warmer temperatures and bigger repairs cure faster, whereas small repairs in cool weather may take a full day. Below 50°F it may not harden at all so save it for a warmer day.
When it has hardened, sand the surface smooth and apply a coat of primer, then paint your preferred color. That’s it!
Abatron makes a really fantastic product and we keep gallons of the stuff in our shop to repair rotted windows and doors, siding, porch columns, really anything you can imagine. And the great thing about it is that the repairs are permanent. Abatron won’t fall out or fail like Bondo or even water putty. It creates a permanent bond with the wood. When your old house finally gives up the ghost the last piece standing will likely be your Abatron repair.
Here’s an idea of how serious a repair you can complete with LiquidWood & WoodEpox
Abatron is expensive, but in this case you truly do get what you pay for. If you’re not sure it’s right for you but still want to try some, I’d recommend getting the Abatron 24 oz. Wood Restoration Kit. It has small quantities of all four components and won’t break the bank.
As always, if you buy through any of my Amazon affiliate links, you’ll get a great price and give The Craftsman Blog a small commission at no extra cost to you.
Happy patching and don’t be afraid of making that rotted wood repair. Let me know how it goes!
Founder & Senior Editor
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.