Author Topic: underdeck waterproofing  (Read 1792 times)

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Rbob

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underdeck waterproofing
« on: January 02, 2019, 02:38:43 PM »
Brian,

I have read "glass everything and 3 coats of epoxy underdeck"  I am whining like a little girl here ! 

I get that plywood will check from moisture cycling but is it necessary on Nailers and Butt-Blocks?

I plan on using Yellow cedar, Can I  get away with 3 coats of epoxy?

Brian.Dixon

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Re: underdeck waterproofing
« Reply #1 on: January 03, 2019, 05:51:44 PM »

The main point is that you cannot get to, or even see again, anything under the deck so you want to do a good job of waterproofing everything under there, including those outside edges of deck plywood just in case they aren't well protected from the bottom side.  THAT said, note that the light glass 'on everything' under the deck is really for plywood since it is more likely to check than solid lumber.  For the solid pieces, e.g. deck nailers and the like, make sure they are well encapsulated (3 coats) before installing the decking.  I like to give them a good coat first, re-coating end grain until it stays wet looking while curing, then rub a soft putty mix of silica/epoxy into the end grain (and let cure) before the final coats.  The same goes for cracks around knots, screw heads and things like that ... seal them up with the silica mix first, then finish coating.  If you do a nice job, then you don't need to glass (and I don't recommend glassing) the solid-wood pieces that are under the deck.  I like to avoid screws or other hardware below the deck as well ... one less thing to leak water into wood.

Make sense?  Lots of ways to skin a cat, but the point is that you'll never see the under-deck area again so you want to seal it up as best you can - and provide drainage as described etc.

Brian
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Rbob

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Re: underdeck waterproofing
« Reply #2 on: January 03, 2019, 11:18:05 PM »
I feel so much better!  Thank you for your support.


Brian.Dixon

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Re: underdeck waterproofing
« Reply #3 on: January 04, 2019, 08:02:08 AM »
I feel so much better!  Thank you for your support.

Great!  ;D

Brian

The Great Alaskan - Professional performance - Easy to build! - https://www.glacierboats.com  ><((((?> ... ><((((?> ... ><((((?> ... ><((((?>