Q: I recently read your column about the redwood cabins. Can you tell me if the interior of my redwood gutters should be sealed with some kind of preservative?
The house is in the Inner Mission neighborhood in San Francisco and was built in 1904. The gutters are an integral part of the Edwardian decoration on the front of the house and so I want to do the right thing. Or, is the ideal solution (expensive) metal liners?
I’m having trouble getting through to gutter professionals and there is scaffolding up now, so I would like to know if the painter should seal the interiors, and if so, what with. Thanks so much.
A: You definitely should take steps to maintain this wonderful architectural feature of your vintage house. From your letter it’s clear you have a great deal of pride of ownership and that you want to do the right thing.
With the scaffold up and the painters on the job now is the perfect time to do a bang-up job on a maintenance project that may well have been neglected over the years.
Believe it or not, redwood gutters are still available at premium lumberyards. They are milled from kiln-dried, vertical-grained heart redwood. They are expensive, both to purchase and install. They don’t call this wood “red gold” for nothing.
Even if you wanted to replace the gutters, the chances that the new ones would match the millwork on your home are slim to none – and slim just left town. So, you are wise to maintain and restore what you have.
All painted exterior redwood – siding and millwork – should be thoroughly primed on all surfaces, front and back, and edges.
When your house was built, the painters most likely put a coat or two of primer on the inside of the gutters to inhibit moisture penetration. Likely as not, the process has not been repeated. After what could be 100 years, it’s time again.
Have your painter clean the dirt and debris from the inside of the gutters. He or she can either wash them out with a garden hose, or sweep the dirt out with an old paintbrush. After the gutters are clean and dry, apply a heavy coat or two of oil-based primer to the inside of the gutters.
You might also ask your painter to add extra linseed oil to the primer to enhance penetration and provide extra moisture to what is likely to be some dried-out wood. If there are any cracks, have them caulked.
We don’t recommend metal liners – and not just because they are expensive. But, if you do opt for them they must be installed in a manner to prevent water from entering a seam between the gutter and liner. This would require an excellent flashing job, with the flashing being installed under the roofing and over the seam of the gutter and the liner in such a manner as to ensure that water did not penetrate between the two.
We’d avoid this option because by not allowing the wood to be exposed to the open air you run the risk of creating a condition that could trap moisture between the liner and the gutter. That environment is an ideal habitat for mold, mildew and dry rot.
Occasional re-treatment of the inside of the gutter – every five years to 10 years with another coat of primer – will maintain the moisture balance in the wood and preserve your gutters.
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