Balcony Rooftop Application


I have a client with an addition built on first floor with a flat roof and balcony on top that their previous contractor was supposed to waterproof then put composite decking down. The roof leaks due to improper installation of TPO. Client is wanting me to tear it off and come up with a permanent solution so that it can be decked. I have no clue what direction to take this. It’s texas so you have extreme heat. I don’t like a single ply running up the brick unless I add counterflashing which i should anyway. water runoff seems most important so maybe a metal roof? powder coated to match deck that will go on top? thoughts anyone? pictures link:



I would recommend you refer that Homeowner to your worst enemy.


Oh come on it can’t be that bad? any reasoning why? i could tear out the tpo and use tapered iso from house to edge then go over that with?


We do small roof decks like this on a regular basis. We always use 3 ply modified torch down, mechanically fastened ventilated base sheet, one smooth, one granular. Then go over it with soft surfaces pavers. That way if there ever is a problem you can just unlock the rubber pavers and service the roof.

The railing needs to be redesigned so the wood posts do not penetrate the membrane. There is no long term, permanent, way to seal wood to any low slope product. Either support the railing off the outside wall or use steel posts for penetration.


if the posts are just tied to the joists then would i be able to wrap the wood with metal or what would you recommend as a redesign?


In that situation we normally cut them off and switch to a steel plate with a pin that a new post slides over.

You could solder a 4x4 post cover with a 12x12 flange on the bottom. Install the first 2 plys and slide it over the post, setting the flange in cement. Prime the flange and install the cap sheet, laminating the flange bewtween plys.


Remove and redo the railing system when the roof is replaced, what MPA is recommending is ideal for a railing system.


well i have to tear the TPO off if i am touching it period cause of excessive leaks it would be a good idea to not layer on top of mold right? would you try to taper it more with ISO board or maybe add scuppers?


Everything gotta go. Like I said we do A lot of these type of little flats. Rip it all off, fix the rot, always is rot, and go from there.

Take a look at soft surfaces interlocking pavers, not cheap but easy to install, they do not interfere with drainage or the roof system.


i love the concept but this is a historical home in the millions and it’s a very old style so i doubt they go for that. how are decks like composite decking typically attached to flat tops like this? seems like too many penetrations for my liking. what if i tore it out and went with epmd without hardly any seams and then installed counterflashing off the brick house because that seam against the house is the scariest part of this no?


Very old historic home… do flat seam copper, good for another 100yrs.


It is possible to use modern material and keep historically accurate. This is a 3 ply modified, pvc railing set on steel pins,

and pavers.


nice. pardon my ignorance, but these “steel pins” tie in how? substrate is plywood then wood joists and I believe posts are tied to the joists. and how did you flash to the stone on the main dwelling? is that copper counterflashing?


We weld a 2" steel pin to a 16 x 16 steel plate and set it on top of the second ply in a bed of cement, then screw through the deck into framing. Then prime the plate and install the final ply over the plate. The wall flashing is soldered copper set in cement and laminated bewtween the 2nd and 3rd ply, then Countered with copper.


i’m with you and see a real solution here. I am not visualizing it well though.


If the homeowner is willing to pay enough to do it correctly, different story than my comment. More often than not, they won’t. And it ends up being an ongoing headache.


This thread makes me smile.