Elastomeric coating on T&G Covered Porch

ptb123April 18, 2014

I'm in hot, humid, SC. I have a 300 ft wrap-around porch with a T/G non-treated 3/4" pine decking. I'm told it was called "oiled pine" when house built in 1983. It is totally covered and I have eves with gutters and gutter spouts every 20 feet which carry water away from house via 4" piping. I'm in a real pickle now because I've tried as best as possible to seal underside of my house and because porch foundation is contiguous with main house (only piers between main house and porch), it has a vapor barrier all the way out to outer brick wall at edge of porch and all foundation vents are sealed. I have a dehumidifier under house and continuous blower fans in vents at ends of foundation. Infrequent heavy blowing rains and pressure washing put way much water on porch and water seeps thru T/Gs. After every blowing rain or P/W I squeegee deck. I think I can prevent this infrequent water intrusion by using elastomeric since it is breathable and durable. However, I cannot go down to bare wood again to just seal wood because it's only 3/4" oiled pine and was poorly sanded once to remove Behr W/B paint (used because of impending VOC laws) applied over Thompsons water seal and stain. After that applied had problem solver primer (basically closed off pores of wood) then coated with Cabots solid alkyd stain. Had vapor barrier installed and underside sealed, was advised to use SW treadplex. I can maybe deal with heavy rains by squeegeeing but anytime a pressure washer is used to clean house, too much water goes under porch. decking and using the TWP100. There are almost no cracks between my T/G except near the edges where the blowing rains hit.
I'd appreciate any advice on if i could caulk cracks then use elastomeric. If anyone has any experience with the elastomerics, I would appreciate it because it looks like
elostomeric will work to stop h2o intrusion and still allow the wood to breathe. I don't know if any of you are near the Summerville, SC area and if so, what consulting fees are but I'd appreciate some expert advice on this--I do not sleep because I've totally sealed underside and roof yet this problem remains a sword of Democles. BTW, sorry but Termite people will not allow total vapor barrier separation between main structure and deck. Again, sorry for the long message, but I would appreciate a response.

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We have a large covered deck, not t&g, that gets water under it from washing the deck or from rain, but I've never had to worry about any water under the deck since it evaporates fairly quickly. What also helps is that we have a perimeter between the deck and the house but the deck was built as though it is part of the house with a full perimeter foundation and a moisture barrier covering the ground and up the sides of the walls (at least 4' high).
I don't understand why you can't separate the deck from the house with some type of wall or barrier but I also don't know what's required for the crawl space air in your region.

I've used the elastomeric deck coating on a small deck + ramp and found it to be very water tight and durable. Sorry, not sure if you should caulk any cracks since it would depend on how large they are, but most deck coatings will fill small cracks.
I would talk to the manufacturer of the deck coating you're considering.

    Bookmark   April 21, 2014 at 4:32PM
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