Fixing a ponding problem


#1

I have black tar over plywood roof. There was coating applied before a few years ago. There is a ponding problem and a layer of tar is gone. the decking is now exposed. Does anybody have any ideas how to fix it. See pictures

I found in home depot this thing 885 Tropi-Cool 100% Silicone Seam and Repair Roof Sealant. I was reading reviews and somebody suggested to use this first and then on the top to put 2 coats Silicone Roof Coating The same company makes that too. This is their video from youtube https://www.youtube.com/watch?v=Wz_9I8n2he4. If you read reviews in the video, somebody recommends using rubberized emulsion with the membrane.


#2

You need a new roof in that area anything less is a temporary band aid.

Coatings are to extend the life of a roof that is in somewhat decent condition to begin with, they are not a roof in a can.

You need something like PVC, EPDM, Modified bitumen or other membrane type of roofing for low slopes.


#3

Two things about coatings-

-Acrylic coatings (which it looks like you have) are NOT suitable for ponding water whatsoever. Silicone is.

-preparation is KEY for installing any new coating. The roof will have to be cleaned, dried, and primed to receive a new coating if you go that route.

The unfortunate part of installing a new roof section over the trouble spots is the inability to “mate” properly with the coated roof. You will most likely need a new roof unless you re-coat with a Silicone.