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How To Seal Tyvek Terminations At Wood And Composite Trim?

How To Seal Tyvek Terminations At Wood And Composite Trim?

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  #1  
Old 08-02-14, 03:23 PM
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How To Seal Tyvek Terminations At Wood And Composite Trim?

Hi,

Tyveking then vinyl siding over t11. It's only the side of a building so there's no tyvek outside corner overlaps.
I'm keeping the existing 1"x5" verticle pine corner trim, pine bargeboard along roof shingles, and composite window trim. There's no soffit (easier for water to penetrate).

Tyvek's pdf says tape or seal all terminations. If I tape it, I would have to cut the tyvek 1/2" short and reply on the tape holding for 50 years or something which I don't trust on painted, rough t11. If I tape it like an inside drywall corner half on tyvek and half on the 1" of pine trim/composite, then when the tape eventually peels away, water can probably enter easier than if I just bring the tyvek tight to trim and do nothing more.

They tape Tyvek like an inside drywall corner here at 3:40, there's at least a soffit though.

http://www.youtube.com/watch?v=kZeoR7cEEc0#t=215


The moderator of the siding forum here says silicone the joint.
http://www.doityourself.com/forum/ex...housewrap.html

But they're talking brick, not wood, so is the best option to use np1 polyurethane sealant which sticks to wood better than silicone? Polyurethane sealant is also recommended for pvc trim, and silicone might be incompatible.


So in other words, run the tyvek tight to the wood and composite terminations, caulk right behind the tyvek edge, press it down then caulk again to seal the tyvek to the wood/composite?

someone suggested sliding aluminum sheet under the trim and sticking the tyvek tape to that, or what about pulling the trim out and putting the tyvek behind it instead?


Also, the windows might not have been properly flashed when installed, but I think it might just be risked to leave them how they are instead of pulling everything out and checking since it's a garage wall with no electric or anything behing the windows, it's not really my choice. So although I know that half say to never caulk between J channel and a window, in this case, if it's decided to not pull out the windows and trim and redo the flashing, should I space the j channel 1/4" from the existing composite trim, backer rod then polyurethane sealant?


thanks.
 
  #2  
Old 08-06-14, 12:53 AM
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I'm just going to remove the fasica/bargeboard and reinstall them over the tyvek... Becuase it seals better and is cheaper than tucking flashing under them especailyl since it's pressure treated t111 which will eat away at aluminum flashing, mayeb galvanized is okay and cheap, but copper/vinyl isn't cheap flashing and I already have the tyvek.

If really need be, then yes caulk behind the tyvek termination. From tyvek about best caulks to use:


Most sealants, butyls, polyurethanes, silicones, and acrylic latexes, are chemically compatible with DuPont™ Tyvek® membranes and DuPont FlashingSystems top sheets; however, not all of these sealants will exhibit high adhesion. DuPont assumes no obligation or liability whatsoever for the use of other manufacturers' sealants with our products.

http://www.dupont.com/content/dam/as...FIN%2010.2.pdf
 
 

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