If you have a cedar shake or shingle roof and want to double or triple its life, read on.

Anyone who's had a cedar roof knows that that rich buckskin color of the shingles quickly disappears as the elements paint the roof a sullen gray. It is the intense ultra-violet rays of the sun and not rain that do most of the damage to wood shake and shingle roofs. Wood roofs can lose virtually all their natural resins and preservatives in as little as five years, resulting in cupping, curling, splitting and decay. But with proper care and maintenance the life of a wood roof can be extended.

Under no circumstances is roof care an option for a roof that is badly in need of replacement. If a shingle roof is over twenty years old (twenty-five for shake roofs) chances are that it is need of replacement and any effort to restore it will be futile. In some geographic areas, the life span is reduced to about fifteen years due to conditions that cause more rapid deterioration.

Roof care and preservation can be accomplished by any homeowner unafraid of heights. Never work on the roof when it is wet and always wear shoes or boots that offer the greatest amount of traction.

The roof-care process is broken down into three steps: cleaning, repair and protection. Keeping the roof clean is one of the most effective ways to prevent damage. A roof covered with pine needles, leaves, moss and other debris will not drain properly and hence will retain water causing the shingles to rot prematurely. Frequent sweepings with a stiff bristle broom will enhance drainage and cut down on fungal infestation.

One of the best ways to clean the roof in preparation for application of a preservative is with a power washer. This device, which can be rented for about $50 to $75 per day from a tool rental or paint store, delivers between 1500 and 2500 psi using four to six gallons per minute. A simple power-washing takes only a couple of hours for the average house and will restore a roof to very close to its original rich buckskin color. When using the power-washer hold the spray tip approximately 8 to 12 inches from the roof's surface while working from the lowest part of the roof up to the highest part.

Step two is the repair or replacement of damaged shingles. Wait until the roof has dried before replacing any damaged shingles with new ones. With the blade of a hack saw, cut the nails anchoring a damaged shingle and carefully remove it. Use the removed shingle as a pattern to custom cut a replacement shingle. Slip the shingle up and under the building paper until the butt end is within one inch of the adjacent ends. Next, toenail two hot-dipped galvanized shingle nails as high up as possible without damaging the butt end of the overlapping shingle. Use a nail set to finish driving the nails. Finish the repair by placing a wood block against the butt end of the new shingle and strike the block firmly with a hammer. Drive the shingle until it is in alignment with surrounding ones.

The final step is the application of a preservative to restore the natural oils in the wood fibers, safeguard the roof from fungus and rot and protect the roof from the harmful ultra-violet rays of the sun. There are both oil-based and water-based preservatives. The oil-based preservatives are best for arid climates where the wood's natural oils are most likely to evaporate causing the wood fibers to deteriorate and separate. When considering an oil-based preservative, be wary of linseed oil formulations. They have consistently been poor performers. Linseed oil is a natural food source for mold, mildew, and fungi. The greatest disadvantage of oil-based products is that they are not as environmentally sound as water-based products.

Water-based preservatives are generally less expensive than oil-based products and have less potential for environmental troubles. On the other hand, an oil-based preservative does a great deal to replenish the wood and protect it from sun and heat. Studies indicate that oil-based preservatives penetrate deeper and help combat weather stress better.

Non-pigmented preservatives can have pigments added to provide further ultra-violet protection.

Because many of the suppliers and manufacturers of preservative treatments cannot, by law, or will not sell to the homeowner in small quantities, consider using the following ready-to-use treatments:

1. TWP Roof and Deck Sealant, AMTECO, Inc., (314) 436-4811 2. Natural Seal Clear X-100, American Building Restoration Chemicals, Inc., (800) 346-7532 3. Cunapsol 1 (pigmented water-base), Blairtown Distributors, (800) 524-1093

Although most homeowner preservatives are applied with a garden-type pump sprayer, an airless paint sprayer, which can be rented, works better. The preservative should be applied in the same fashion in which the roof was washed working backwards from the low end to the high side. Be careful not to walk on a slippery treated area.

Regardless of the method of application, be sure to wear protective gloves, clothing, a face mask and safety goggles to avoid illness or injury. Apply the preservative when there is no breeze and the air is still. This will ensure that the majority of the product ends up on the roof and not on your neighbors' car.

Most preservatives will last three to five years, depending upon the climate. Keeping the roof clean and debris-free will help extend the lasting quality of the preservative and therefore the life of the roof.