Post Number: 476
|Posted on Saturday, July 10, 2010 - 06:14 pm: ||
I have used Grace before too, and at the lap where a bit of the bitumen is exposed, it is impossible to get it apart. Put the 30# felt over the whole thing.
Post Number: 64
|Posted on Thursday, July 08, 2010 - 04:23 pm: ||
It REALLY depends on the type of IWS being used. Almost granular types are horrible with sticking and makes it ridiculous to try to repair later, but some of the other IWS like Grace has a plastic like top that isn't bad. Probably the best for this is Polyglass TU Plus. It has a polyester fabric on top and doesn't stick at all. It's specified on almost all the jobs we've bid in Florida.
But as Blue Sky said, don't rely on the underlayment as your "line of defense".
Post Number: 22
|Posted on Thursday, July 08, 2010 - 03:59 pm: ||
As Joe said... the 2nd guy is CORRECT! Take it from one who has ripped off a roof (shingle) or 2 where I&W was present - might as well rip off the wood decking. This is going to be a MAJOR - MAJOR headache for roofers in the near future.
If the I&W has a plastic top layer (such as Grace I&W) than it probably is OK to leave 'uncovered'; but if it is like most that have a granular surface, then put a layer of felt paper over top to act as a divorcing material between I&W and the slate/shingles.
CAUTION: When installing felt over I&W on a 'walkable' roof, use simplex nails or staple / nail the heck out of it. The felt likes to 'move' on the I&W with your body weight. I always install the felt 2" higher than the I&W so that the top 2" is stapled to the wood deck
ALSO: Don't be fooled into thinking that I&W is the 'ultimate cure-all' for leaks. I have seen it fail. It is not going to have a perfect seal around EVERY single nail penetration. (Make sure your first 'line of defense', is your best 'line of defense' - don't depend on your 'back-up system').
Post Number: 180
|Posted on Thursday, July 08, 2010 - 03:37 pm: ||
Since only the top edge of the slate touches the ice and water shield and it's not sticky on the front side , the first option is viable .
I've repaired several roofs with Grace as underlayment with no problems removing pieces of slate .
Post Number: 557
|Posted on Thursday, July 08, 2010 - 11:00 am: ||
The second guy is correct.
Post Number: 3
|Posted on Thursday, July 08, 2010 - 10:59 am: ||
One slater told me he plans to use IWS for the first 2 feet or so from the bottom and 30lb felt for the rest of the roof. Another told me the same thing only that he also will cover the IWS with 30lb felt as well. Otherwise, he said it would make that portion of the roof impossible to repair in the future because of the adhesion of the slate to the IWS.
Who is correct here?