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What is the difference between Redwood Sapwood and Heartwood?
Learn more about Sapwood vs. Heartwood here.
What type of Redwood Sealer should I use?
Learn more about Sealers here.
What Are The Black Marks In Redwood Lumber and How Do I Remove Them?
The black marks in redwood lumber are the result of an interaction of the natural tannins found in redwood, combined with moisture and contact with metal. As you can imagine, the three come into contact frequently–from the machinery used to take down the logs, to the saws used to mill the lumber into usable sizes– especially during the wet winter months.As the three combine, often times a black mark appears. Although much of the time, the black marks are hardly noticeable, there are ways to further eliminate their presence.
There is an inexpensive product available called oxalic acid. Mixed in very hot water, the product eats away at the black marks, much like a bleach eliminates color. Apply the product to the redwood lumber, and scrub with a natural bristle brush. After your desired result has been achieved (should take no longer then 5-15 minutes) rinse the product off with cold water. This product can also be used to bring to life and older looking deck.
How Much Does Green Redwood Shrink?
As a rule of thumb, figure .7% for every 4% change in moisture content. Thus, a green 2×6 going from 24% to 12% moisture will shrink 1/8 in. Longitudinal shrinkage is about .01%. Thus, a ten foot 2×6 with the same moisture will shrink about 1/4in.
How Do I Make New Redwood Match Existing Weathered Stock?
Apply 4 oz. Baking Soda to a gallon of warm water. Brush on, wait until desired weathered appearance is obtained, and rinse off.
When Do I Apply Redwood Sealers?
Wait two to four weeks in good weather before applying a penetrating oil sealer to unseasoned redwood. If oil sealers are applied to very wet redwood, the oil will not penetrate, and may puddle. If allowed to congeal, puddled oil sealers become tacky and very difficult to remove. Kiln Dried redwood can be sealed right away.
How Much Does Redwood Weigh?
Rough unseasoned (aka green or wet) Redwood can have as much as 24% moisture, and weighs approximately 3 lbs per board foot. Surfaced green Redwood weighs about 2.5 lbs/bd ft. Kiln dry rough Redwood weighs in at about 1.9 lbs./bd ft, while surfaced KD weighs about 1.4 lbs/bd ft.
How Do I Remove Pitch Bleeding?
Remove pitch with turpentine and a shop rag. Pitch bleeding, a response to heat, will gradually stop as the wood becomes fully seasoned.
Bark Up or Down?
Redwood 2×4 or 2×6 has very little tendency to cup. Therefore, when laying Redwood for a deck, a board should be oriented with the bark side of the tree up to minimize grain lifting. With wider face-widths, such as 2×10 and 2×12, the bark should be oriented down to prevent cupping.
Redwood Maintenance
Always keep your exterior redwood structures as clean, dry, and clutter free as possible. Remove debris between redwood deck boards and underneath the deck periodically. Make provisions to collect run-off from planters or pots on a deck. A large plastic saucer can be easily fitted with a flexible 1/2″ drain to direct excess water below the deck.
We do not recommend power-washing redwood decking, fencing, or posts. Even carefully controlled pressure washing tends to removes softer redwood tissue, and can quickly result in a sandblasted look. The process essentially combines the weathering forces of thirty years into one afternoon. Elbow grease is always preferable.
Color Restoration
If color restoration is desired, prepare an oxalic acid solution by dissolving 4 oz. of oxalic acid crystals in one gallon of warm water. Wearing waterproof gloves, apply the solution using a bristle brush, let stand until desired color is achieved, then rinse with clean water. Allow the redwood lumber to dry for several days, then apply an oil based sealer.
Refinishing
Refinishing may be required annually if your site has high sun exposure and you are using a non-pigmented sealer. (Using a pigmented sealer will buy you a few more years while sacrificing a “natural” look.) Just like anything in life, the longer you put it off, the harder it’s going to be. Prior to applying or reapplying any sealer, clean the surface of the deck using a mild detergent or oxylic acid and a non-metallic bristle brush. Rinse and allow the redwood boards to dry for several days. Then apply the oil based sealer of your choice.