Arin in Santa Cruz has a deck problem-
The deck in question is 2nd story solid material with a drain partially over the 1st floor living room. I have owned the home for 3 years and our HOA has recently determined that deck maintenance and repair is a homeowner responsibility, not included in the HOA’s responsibility to repair and replace the roof (due to happen this summer). The deck does not drain properly, there is standing water/pooling during and after rain which this winter has been almost constant. I often resort to sweeping the deck with a broom to push the water into the drain. Although I have not yet seen any actual leaking, I am currently repairing other major water damage inside my home and have become very obsessed with preventing potential problems. I know the standing water on this deck is going to cause a problem at some point and I would really like to improve the drainage, but cost is a major issue.
DeckExpert.com answers your questions about deck waterproofing methods and materials for only $25.00.
“I am building a new roof deck as part of a full house remodel and I found you when researching my waterproofing options. My builder is suggesting hot mop, but I am not sure it is an appropriate option for a deck. The deck is on the plywood substrate and will not be heavily used (it is primarily there due to city’s set back requirement), but I still want to make sure that it can withstand light use. We are planning to install modular deck tiles on top of the decking surface.” Marat B San Francisco CA
Thanks for writing; you’re wise to have done some research and raise doubts about “hot mop” for waterproofing a roof deck.
Today’s modern deck waterproofing systems from our manufacturer’s provide all in one solutions to your waterproofing dilemma. The decking/roofing systems under Division 7 Pedestrian Walking Decks are all tough durable membranes that can be finished to look like wood, tile, stone etc.
Alternatively, if you want a wood deck on pedestals above a waterproof surface, walking deck systems are still your best choice. The coatings can be installed and then pedestals can be placed on top of the waterproofing and a deck system built on top. With this method you should allow for being able to remove the decking to clean the waterproof surface periodically of debris. Extra slope over the minimum code required 1/4″ per foot may help flush debris off. I would suggest draining off roof edges rather than roof deck drains (ThunderbirdProducts.com) as debris may clog drains at the worst possible time. If you opt for drains, use a minimum of a 3″ drain and 3″ ABS pipe.
If you review our site, you’ll find lots of information and advice that should be useful in your quest. Make sure to read, understand and meet all requirements for a waterproof deck system and always use Best Practices to go over and above code which is just a bare minimum. For instance, use 1 1/8″ plywood over the minimum 5/8″.
Good luck with your project, Bill Leys The Deck Expert