Expert: maura macaluso - 6/23/2007

Question
After 40 years we just replaced the cedar siding on our house with new cedar siding. We want to seal the wood with the best long lasting transparent sealer available for the wood. Your recommendation on a product would be appreciated.  The house is about 6 miles from the Atlantic Ocean and storms from the east or northeast does bring some salt in the air, also high humidity.
Thanks

Answer
Red and yellow cedar contains a lot of natural preservatives which if left exposed, will eventually seep up to the surface and turn the wood dark silver/grey.  If this aging process is undesirable for the look you wish to achieve, then you need to treat the wood with a protective coating.  This is best and most easily done before the shingles or siding is installed. it is best to completely seal each piece, front, back and sides, paying special attention to the end grain which would be on the top and bottom edge of each piece.  I am however assuming that the siding is already installed on the house.  The general rule of sealants is to use oil-based in the colder northern climates and latex-based in areas of sustained high humidity. You do not say exactly where you live so you will have to decide which is best for you dependant on your area. If you are north of the Carolinas I would suggest using oil-based. You will also want to make sure that your sealant contains UV protectants. The application also needs to be addressed here.  Hand brushing is better than spraying as there is more control over coverage.  A brush can apply a thicker coating which combined with an alert and diligent worker, can make sure every exposed area is covered. There are no finishes known which will maintain permanent protection and your siding will need to be retreated every 2 years or so.  There are so many products out there that I am hesitant to give you an actual product to use.  what I will do is to recommend Sikkens Brand as a company known amongst woodworkers for excellence in its preservative products.  All in all, knowing that any protectant will deteriorate over time, your wood will only be as well preserved as your maintenance schedule dictates.  If your wood eventually begins to darken you can then use a wood bleach and/or sanding to return the exterior to a lighter color and then retreat again. thanks for the question.