Redwood Exterior Finishing tips

California redwood is one of nature’s most maintenance-free building materials. It has a natural resistance to decay and insects. Redwood’s natural stability means it shrinks, warps, and splits less than most other woods. In addition, no other wood takes and holds finishes better than redwood. 

Best Redwood offers 4 types of Redwood Finishes.

Here are images showing the different types of redwood sealant options applied. From left to right: 1912 -Mission Brown, 1905 -Super Deck, 1910 - Super Deck and Clear No Stain finish.

General Finishing Tips

• Apply finishes on windless days. Temperature should be between 50 and 70 degrees Fahrenheit.
• Surfaces should be clean and dry.
• New structures built with unseasoned wood should air-dry one month before finishing.
• Back-priming is recommended for all exterior finishes, particularly paints.
• Don’t use wire brushes or steel wool as metal particles may become embedded in the wood and can cause stains. Use stiff bristle brushes.
• Use finishes recommended for wood exteriors.
• Follow manufacturer’s directions and read warnings on toxicity.
• Don’t mix incompatible materials. Finish failures may result from mixing incompatible products or applying them over one another.
• Moisture is the most common cause of finish failures, so use proper vapor barriers, air vents and flashing in new construction.
• Saw-textured redwood holds stains, water repellents and bleaches up to twice as long as smooth-surfaced wood.
• Redwood grade marked Certified Kiln Dried will provide the best finish retention available.
• To avoid nail stains, use stainless steel, aluminum or top quality hot-dipped galvanized nails.
• Periodic rinsing with a garden hose will remove dirt and grime from siding. Stubborn build-up can be removed by scrubbing with a bristle brush with a solution of warm water and a mild detergent. Rinse afterward.
• Splash lines can be minimized by an occasional hosing of the unaffected area, which will even the appearance of the wood.

Exterior Finishes Not Recommended

• Varnishes and polyurethanes crack and pool when used for exteriors. They are difficult and expensive to apply and deteriorate quickly Removal is expensive and difficult.
• Pure oil-treatments such as boiled linseed oil, are not recommended on exterior redwood as they tend to promote mildew growth. Quality oil-based finishes, including those based upon linseed oil, contain mildewcides, and are appropriate for use on exterior redwood.
• “Shake and shingle” type paints do not last well on redwood lumber siding.

Finish Restoration

Dirt and Dust may build up to the point that a mere rinsing with water from a hose will not remove them. A mild detergent and warm water will generally remove stubborn dirt and grime.
Mildew appears as dark spots or gray, fan shaped spots on the wood surface.
Severely infested areas may appear uniformly gray or black. To remove a mild case of mildew, scrub with a mild cleanser or detergent. Next rinse with a household bleach to kill surviving spores.
Lastly rinse with water. When applying a new finish, be sure it contains a mildewcide. For more information see our: Maintanance and care link.

Note: Household bleach should never be mixed with detergent containing
ammonia. Fumes can be fatal.
For severe mildew infestations, scrub with a stiff bristle brush using a solution of one cup of trisodium phosphate, one cup of liquid household bleach and one gallon of warm water. Rinse thoroughly. If necessary, follow with an application of 4 ounces of oxalic acid crystals dissolved
in one gallon of warm water in a non-metallic container. Apply evenly with
a soft brush.When wood dries, rinse with water. Caution: Oxalic acid is poisonous, but not dangerous if precautions are taken.Wear rubber gloves. Avoid contact with skin or eye.