I have a flat rubber roof that has an intact membrane, but it is ponding to a depth of 3/4 inches in some places. Is Liquid Butyl Rubber an appropriate product for this application? What is the maximum thickness per coat?
If Liquid Butyl Rubber is not the best product, what do you think the best product is?
A deck was improperly installed over the rubber roof 20 years ago, attaching a facia around the perimeter of the deck that prevented water from draining off. Consequently, water pooled up to a depth of several inches until occasionally it would back up into the adjoining wall and into the house. This could have damaged some joists, causing a change in pitch of the roof, so I'm having a professional look at it to assess whether the entire roof needs to be replaced. But if it's structurally sound, then I need to fill in the ponded areas and provide drainage by removing some of the fascia and installing a gutter, and this repair might not be too expensive to fix.
After fixing the ponding, I intend to re-install the deck above it (which rest on "sleepers" above the rubber roof), so there won't be any sun hitting the rubber roof directly.