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Shifter 10-16-2010 04:58 PM

New Rubber Flat Roof w Ponding Problems
We just replaced the entire upper roof with Firestone EPDM .60 Gauge rubber. The insulation underneath was replaced with 4 inches of insulation board. The base is corrugated steel.

A ditch had formed from ponding in the old roof along the right edge, just 10 years after the last entire rubber roof replacement. We asked him for a quote for fixing just that area. He gave us a quote for that, and a quote for the entire upper roof. We decided to do the entire upper roof. The ponding is happening in the same areas as before.

He wrote any additional work on low lying areas would be additional, and that we wouldn't know until he tore it off. When he did tear it off, he said he felt it had good slope.

He was told that we didn't want water going beyond the drain and ponding in the corner of the roof. During an average rain, the water is going over the edge of the roof and coming through holes in the facia. During one extremely hard storm, there was a huge waterfall coming over the edge.

After 72 hours of 78 degree weather, there was a still over a half inch of ponded water in one corner and 3/4" of water in the other corner beyond the drain.

I'm concerned the same thing is gonna happen, another ditch could form and we may not get the 20 years that the rubber has for a warranty. This roofer claimed to be a flat roof specialist.

Does he need to come back and put some slope or a drain in these low lying areas? Would you consider this work acceptable? I've read the ponding should dry within 48 hours, do you agree? Greatly appreciate the help.

Picture of right rear of roof, 72 hours of near 78 degree weather after last rain 3/4" deep

Picture of right front of roof, 72 hours of near 78 degree weather after last rain 1/2" deep

Picture of right rear of roof, 48 hours of near 67 degree weather after last rain

2 drain pictures, drain holes seem too high and draining very slowly

RoofDiagnostics 10-17-2010 03:24 PM

As for being acceptable, that is really up to the consumer. As far as the funtionality of the roof system: EPDM can withstand ponding. The only concern i would have, is if there were any roof penetrations in this area (ie: chimney or vent stack).

Looking at the pictures i did not see any penetrations. So, if the roof was installed properly i would not suspect leakage problems now or in the foreseeable future.

If you find the ponding unacceptable, the 'most efficient' modification would be to install a "cricket" in this area, pushing the water to the properly pitched portion of the roof.

As a point of reference, my company typically provides pricing options for roof surfaces with and without ponding. We DO install some roof areas that we expect to have SOME ponding - this has never been a problem for us.

Hope it all works out,

johnk 10-18-2010 08:07 AM

Take a hike spammer,or I'll show you my hammer:eek:

Grumpy 10-18-2010 08:42 AM

The 3rd picture witht he drain is not really a problem other than I would have expected the insulationa round the drain to be sumped a little more than it is, but honestly it's fine. The first picture I can't tell if it's the same area and you just removed the drain basket? Really in my opinion based on the pictures it's acceptable. But maybe you're seeing something the pictures are not showing.

Keep in mind I've never seen a flat roof ever without some degree of puddling.

In the 2nd picture about a foot above the puddle, what is that depression?

I'm not a fan of the way they did their edge metal/fascia.

RoofDiagnostics 10-18-2010 08:49 AM

Grumpy - "I'm not a fan of the way they did their edge metal/fascia."

I agree, the perimeter metal should be stripped in with peal and stick epdm cover strip.

Shifter 10-18-2010 03:55 PM

Thanks for your comments. In the first picture, the drain is just out of camera view and no the drain basket was not removed. You asked what is the depression in the 2nd picture, I believe itís just a spot where the rubber wasnít pulled tightly enough? I really donít know what happened there, any thoughts?

So whatís the reason for using peel and stick epdm cover strip around metal fascia edge? He never suggested that to us. I am concerned that during just an average rain, water leaks through gaps in the fascia and falls on the walkway below. This is because the water is going over the right rear edge of the new roof.

Grumpy 10-18-2010 08:25 PM

The way the fascia is, it is simply a cladding... which is the nature of fascia. Typically we will strip in the roof with a gravel stop and then slide the fascia beneath the gravel stop. Sure you could strip in the fascia that's there without the gravel stop, but the exposed flange is about 2" and you'd want about 3" to properly strip in.

So the reason? Well if a drain were to become plugged and water were to back up, it would back up under your fascia and eventually rott the wood fascia beneath. I have seen it many times where the siding crew comes in after the roofing crew and clads the fascia. Is it wrong? Well I wouldn't do it, but it probably also wouldn't void a roof warranty either since it technically isn't a roof. However I'd be interested in seeing exactly how the membrane was terminated behind that aluminum fascia cladding. If it is not properly terminated that might void a warranty... not like you'd have a manufacturer warranty on residential anyways... This is residential, isn't it? Oh and not just water back up from a clogged drain, but wind driven rain can back up behind the fascia as well.

Shifter 10-19-2010 05:36 PM

I really appreciate you taking your time to answer my questions!

I was wondering how this problem with water in the corners could be solved. The one corner near the drain is a real problem because water is cresting over the edge during average rain storms.

I was reading about these:

Perimeter tapering system
Economical method to shed water away from critical areas at parapets, walls, mechanical units, etc. The majority of roof leak problems occur at vertical penetrations of the roof system so it is vital to shed water from these zones. Consider widths between 4' and 16' with minimum slope of 2%, for Perimeter Taper Systems.

So can I get tapered insulation for just the two corners of the roof?

What about step sloped insulation? I found this:
Step sloped insulation is a more affordable way to slope a flat roof and it involves installing several layers of flat board insulation under the roof membrane instead of cutting a custom-made roof board. The board is installed in steps with the thinnest boards at and around the drains. Then the roof membrane is then installed over the step sloped insulation.

I'm gonna take some pictures tomorrow of how the membrane was terminated behind that aluminum fascia.

Grumpy 10-20-2010 10:58 AM

Tapered insulation, what I think your post was calling steep slope insulation, would be probably the best way to reduce or eliminate the puddles. It's going to be kind of hard now though.

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