How to protect a wood-shingle roof

To the real estate editor:

Enclosed you will find the process for applying raw linseed oil and graphite to a wood-shingle roof. This appeared many years ago in your column, and I am still getting letters from your readers asking questions.

None of us can afford expensive repairs, especially if there is a sure-fire way to avoid them. I have had tremendous success with this process.

* First, the roof to be oiled must be put in A-1 shape. There should be no loose shingles, or missing shingles, or badly split shingles. All loose shingles should be secured, and repairs made to provide a good water shed.

* Second, the surface should be swept clean of all leaves and debris, as well as from vines, moss, or any other extraneous material, including dust. Clean the gutters thoroughly.

* Third, the surface should be thoroughly dry.

* Fourth, the graphite and raw linseed oil should be thoroughly mixed and allowed to stand at least 24 hours before applying. After it is mixed, the most convenient-size container it can be stored in are 5-gallon buckets. The mixture is composed of 1 pound finely divided graphite to each gallon of raw linseed oil. There are different graphites so be very careful to get the proper fineness.

* Fifth, the shingles should be thoroughly drenched with the mixture -- literally soaked. The best way to apply the mixture is with a spray wand about 6 feet long. A pressure pot of at least 5 gallons' capacity should be used, and an air compressor that will provide 60-pounds-per-square-inch pressure at about 2 cubic feet per minute.

At least 100 feet of hose should be available, depending on the height of the roof above ground. A roof of any size will need at least 55 gallons of oil, so the oil should be bought in a 55-gallon drum. There is a large price break available this way.

If you have any problems, please feel free to contact me.

Arden D. Zimmerman 1650 The Alameda San Jose, Calif. 95126