Restoring Structural Integrity to Rotted Logs

No one wants it to happen but dealing with rotted logs doesn’t have to mean the end of the world or a huge expense.

If you have rotted logs to repair fear not. The first thing to do is to figure out why the rot is present and fix that problem.

Here are some common conditions that promote rot:

  • Leaky gutter or down spout that allows water to run down the logs
  • Large check or crack on the up-facing part of the log that collects and holds rainwater
  • Garden sprinkler system that sprays the walls of the house
  • Horizontal beam/log surface that allows water to sit on the surface and be wicked back into the house
  • Log ends or ridge beam that extend past the protection of the roof
  • Vegetation or flower boxes holding moisture next to the walls
  • Earth in contact with log
  • Porch attached to the bottom log instead of spaced properly to allow for water drainage
  • Interior leaking plumbing
  • Exterior faucets that are drilled through logs
  • Paint used on the logs instead of a quality log home finish/stain

Some of these fixes are easy and some may require a professional but it’s very important to make sure the conditions that promoted the rot in the first place are corrected before you try to restore your logs.

If the wood is all or mostly there and your home is not experiencing structural failure (i.e. the log is not crushed) then you can often restore the wood with a 2-part epoxy product called Liquid Wood. Even wood that would crumble under finger pressure can be restored.

Before you use the Liquid Wood we suggest you consider applying borates to the area first. Borates can stay in your wood for about 40 years and are a good preventative measure against decay and insects. Borates need to be applied to bare wood in order to penetrate properly. Often this is not an issue in severely rotted areas — just saturate the wood by brushing or spraying. You can also inject the solution into the spongy wood. We carry 1-1/2 pound borate packs for small projects. Borates will not change the color of the wood and may take several weeks to fully migrate into the log. Sometimes crystals will form on the log’s surface which can be brushed off before you proceed.

Allow the wood to dry before you use Liquid Wood. Liquid Wood can be injected or poured into the log where it will surround the existing wood cells and basically petrify them. You drill small holes and then use a large (60 cc) syringe with or without a large gauge needle to inject the Liquid Wood into the log. These syringes can be purchased at farm stores or veterinary supply stores. You won’t need to drill if the wood is really spongy. An excellent application for Liquid Wood is a hollow log. I’ve tested logs before they were treated with Liquid Wood and then a day afterwards and the difference is amazing. You’ll go from hollow to rock solid. Just be sure that the log’s entire outer shell is still intact before you blithely pump several gallons of the material into the cavity. One of our customers hadn’t realized that his hollow log had a gaping hole on the interior face and he ended up with quite a bit of Liquid Wood in the crawl space before he realized what was happening.

There has been a lot of talk on the internet lately about penetrating liquid wood epoxies. While Liquid Wood does penetrate wood very well, these “penetrating” products use additional solvents and are able to penetrate more deeply into the wood with a resulting loss of structural capabilities due to being. Liquid Wood does not contain solvents but you can thin it with acetone if you’d like to make your own (more) penetrating liquid epoxy. The manufacturers of Liquid Wood suggest that you mix in no more than 15%. Keep in mind though that you will reduce the structural strength by diluting it with acetone.

Occasionally,  restoration specialists will use a slightly diluted liquid epoxy first to penetrate as deeply as possible then use regular strength Liquid Wood for the balance.

If the rotted area of your log has wood missing and a large hole is staring at you you need a different approach. Liquid Wood can be used as a primer but you’ll need Wood Epox a 2-part putty type system to fill the void. This product can be shaped while still soft and can be nailed sawn drilled painted etc. when cured. Because it dries white you can use dry tints to mix in to match the color of your logs or you can paint it a light tan color and then apply your log home stain/finish over the top. You don’t have to use 100% Wood Epox to fill the void you can use other pieces of wood to take up some of the space. As with our discussion of Liquid Wood earlier consider an application of borates to the cavity wall before you proceed. Once you complete the patch you can’t apply borates; they won’t be able to penetrate the epoxy to get to the wood beneath.

Either you or the professional you hire will need to be the judge of the condition of your logs and what can be repaired and what should be replaced. If you have an extremely ugly and rotted log right by your front door you may want to consider replacing the log or the log face. Even a careful restoration may not look original especially since you won’t be putting paint over the log to hide it. For reasons against using paint on log homes please see the Restoration #1 article at the web site newsletter library. For information on replacing logs read our Restoration Part 3 article. While log replacement has its rightful place in the restoration industry often you can save substantial time effort and money by using the epoxies mentioned here.