Q: We have just sandblasted the underside of our redwood deck to remove all of the paint the previous owner used. We now want to seal and preserve it so it won’t have to be done again for 10 years.
The deck is on the east side of Lake Tahoe with full sun on the top. It is about 30 feet off the ground and the underside gets no direct sun. Moisture is a problem due to snowmelt.
We don’t want to stain or paint because of the time and expense. The cost for labor alone is more than $700 for one coat only. We want a "once and done" solution. What would you recommend?
A: Job one is to protect the wood. If you think regular maintenance is expensive, imagine the price of replacing a redwood or cedar deck that’s 30 feet off the ground. It’s true that you won’t have to seal the underside as often as the top, but 10 years is pushing the envelope.
There isn’t a product out there that will hold up for a decade of Sierra weather. Best case, you can expect to reseal the underside of your deck every three to five years.
With that in mind, we think you should consider making this ongoing chore easier on yourself or on the people you hire. Consider building a scaffolding frame 8 feet below the bottom of the deck boards. Because the snows have come early to Tahoe this year, you’ve got plenty of time to plan the project for the next spring. We envision stout boards attached to the posts supporting the deck to provide a place to support scaffolding planks when doing regular maintenance.
Horizontal 2-by-8s or 2-by-10s can be affixed to the posts with carriage bolts and braced with diagonal boards to provide stability. Presuming the deck is a rectangle you may need one or several intermediary "joists" for the frame. The extra lumber does double duty. It’ll be scaffolding for deck maintenance, and it will provide extra bracing for the deck.
If you decide to do this, there a couple of musts:
1. Get a permit from the local building authority. They will assist you in sizing the boards. They also may require that you install handrails.
2. Make sure whoever is doing the maintenance uses enough planking for safety.
3. Even if the building authority does not require it, have temporary handrails around the perimeter while work is being done.
4. To treat the bottom of the deck, use the same material as you do on the top. From the new platform, spraying or rolling won’t be any bigger chore than it would be if the deck were affixed to the second floor of a building on flat ground.