For Flat Roof With Ponding, is Torch, Mop, or TPO better?

I have a flat roof in So Cal with some areas that pond, and I am wondering if I should use a torch, hot mop, or thermoplastic If Thermoplastic is the way to go, which brand … Fibertite, Durolast, IB, Sarnofil, etc. I have HVAC ductwork on the roof that was set 2-3 inches above the roof, so I do not want to reroof again for a long long time. To re roof now requires removing all of the existing ductwork and then reinstalling… What a pain and expensive. I want a roof that is going to be as impervious to ponding as possible, as I think the ponding is what has caused the problem. Thanks. I am also trying to decide whether to rip off the roof, or try to put thermoplastic directly on top of existing roof. Please help if you can! Have to decide this quickly as it might start raining in the next few days.

tear it off, taper it so it dont pond and reroof with
torchdown or bur, or you will allways have problems.


Sarnafil or IB PVC would be good,as would any EPDM rubber roof. You should consider using tapered insulation to eliminate the ponding issue.

I agree that you should do tapered insulation, which unfortunately is VERY expensive. However if money is a concern and you have maybe an inch or two of ponding water, you can get away with not doing a tapered system. Your roof stood up so thus far…

For the roofing system I recommend IB, which is what we install. It is warranted for ponding water and will not leak. It is also a cool roof, which is VERY important in Cali.

I hear that Sarnifil is a decent system, bu have zero experience with it, therefore can’t really recommend it. It is essentially similar to IB.

Stay away from tpo! Don’t use bur as it will not take ponding water, it is heavy, it’s not a cool roof… it s basically a thing of a past… Epdm also should not be used in a ponding water situation.

A quality Spray Polyurethane Foam ROOFING contractor can hook you up.
(Dont use the foam insulators that have no roofing experience or knowledge)

A good SPF roofing contractor will be able to advise you and will (if your roof is a candidate for SPF) be able to taper the foam roof to the drains.

If properly installed and maintained, you should never have to repalce a foam roof.

You will, however, have to perform minor caulk repars (like any properly maintained system)and recoat it every 10-20 years, depending on the coating/sprayable membrane system you invest in now.

Polyurea on top of the foam can last upwards of twenty five years, with accelerated weather testing showing an expected life cycle of about 75 years with a pure polyurea rather than a hybrid.

With a pure polyurea, you can get a white topcoat that will last ten times as long as an elastomeric acrylic of the same thickness. The reflective white polyurea will gain Title 24 compliance also.

This roofing system is a win-win-win.

Epdm is very water resistant. In fact its used as pond liners exclusively. Tpo is also a good white membrane. Id stay away from Pvc,s they are made from chlorides which are toxic to the environment and plasticizers which will leach out over time and the material will stiffen.

Well you have heard everyones concerns. Mop down or BUR and modified systems will break down over time in ponding water areas. A pitch mop down will not break down But a lot of contractors do not apply this anymore. EPDM, TPO and PVC. have all been used for man made ponds and do very well. If you have a ponding issue I would want to get to the matter of why this is happening. Tear it off and check the Integerity of the structure. this could be the problem. If the structure is fine then apply a taper insulation system. this can be produced by your insulation supplier. Then apply the system you like best.
Good Luck