Expert: Greg Scholl - 5/20/2010

Question
QUESTION: Need advice on best way to treat cedar tongue and groove.  Application is outside porch ceiling.  Not exposed to direct sunlight and moisture.  Looking to protect from humidity and change in temperature.  Goal is to enhance beauty of wood and minimize maintenance.  Your suggestions and advice is much appreciated.

ANSWER: Hi Ron, a penetrating oil product is probably the best bet, but be aware that Cedar, (especially old and/or weathered Cedar)is VERY soft, and will soak up anything you apply to it like a sponge.....this can make application tricky as well to eliminate lap marks, and get an even finish...so you will need to apply evenly and quickly working with the grain, and possibly wiping down as you go.....if this ceiling is something you're actually applying, and it will be blind nailed, then prefinishing is the best way to go, and will be the easiest way to get an even application to each board....if it's already installed it's trickier....and much more hassle. WaterLox Original or Watco (available in natural or colors), are probably decent choices....post back if need be.Regards- Greg

---------- FOLLOW-UP ----------

QUESTION: When you say, "a penetrating oil product" do you mean Urethane?  Tested Urethane on piece of cedar and is taking long time to dry 36 + hrs.  Can you better explain "wiping down".  Urethane product will be hard to do.  How best to do?  Can it be thinned?  I know these are a lot of questions but want to get it right.  Ceiling is being applied so finishing before installing is easier.  Thank you.

Answer
NO ..urethanes are a surface film...the thing you do NOT want to do on Cedar, Ipe, Teak, etc...(naturally resinous woods)....is this new wood? It sounds like it, as the resin in new Cedar will keep many things from drying....please check out the two products I referred to........and read the product descriptions and uses. I wouldn't thin these, they are supplied ready to use, and thinning increases the risk of lap marks and blotchy drying. One would apply these to a super soft wood like Cedar working quickly, with a brush, sprayer, etc., then immediately wipe the product off evenly and well, making sure to apply an even,THIN, uniform coat.As with any penetrating finishing product, thin coats is the way... These will dry flat to satin depending on the amount of coats, but Cedar will soak up many coats...(of anything). These products 'penetrate' the wood and harden from within...they won't ever flake, chip, peel, etc....because they are not surface finishes.........Thompsons is also a decent product......


http://www.waterlox.com/products-item/waterlox-original-penetrating-tung-oil-flo


http://www.woodcraft.com/Catalog/ProductPage.aspx?prodid=1999&ss=de757f50-73ec-4

http://www.thompsonswaterseal.com/products/waterproofers_total_wood_protection.c