We can’t believe how many times we’re been called in to look at failing wood retaining walls that had gone south well before their time. If only they had been built right in the first place, the owners could of saved hundreds if not thousands of dollars in time and expense repairing or replacing them.
When you or your general contractor buy the wood that has been treated (waterproofed) it’s all good. This is specially prepared wood made to come in contact with the ground and water, so it has a waterproof layer that will protect it for a long, long time. The classic wood used in retaining walls is railroad ties that have been treated and are ready to go.
Where the trouble starts is when you cut the length of these treated timbers to the size you need. Time and time again we see this mistake, where the water proof wood is cut, and the now vulnerable wood where the cut was made, is left exposed. You see the wood was waterproofed, that is true, but only on the outside. If you cut the wood you now have a place that is not waterproofed, and if not re-sealed will eventually become a problem.
Exposed wood that is not resealed and directly exposed to the ground or water will soon start to rot, and this rot will eventually destroy the whole timber. Here’s the rub, it will look okay on the outside for years to come, and you think it’s all okay and the job was well done…until one day it just crumbles. What this means is that it’s rotted all the way through, from the inside out. Yep, when you cut that timber and and didn’t re-seal the wood, you leave the door open to wood rot.
I don’t know if it’s ignorance, thinking that waterproof wood means it’s waterproofed inside and out, or some people are just lazy and don’t want to do any extra work. But if you’re building a retaining wall, make sure when cuts are made to treated timber, like your water proof railroad ties, that you get those exposed cuts sealed. This will take a few minutes to apply the water proofing sealant and let it dry, but this will be the difference between your retaining wall lasting 5-10 years or 10-20 years.
The Crew at Aim Higher Construction…Los Angeles General Contractors