Flat roof repair

[tomtheelder2020]

We had a massive, much needed rainstorm a couple weeks ago but the downspout for the flat-roofed section of my mother-in-laws house clogged, the roof flooded and water leaked into the exterior wall of one bedroom. I suspect the water got deep enough that it simply over-topped the edge of the roof barrier. However, it is clear there is enough damage that serious maintenance is needed. The first photo below was taken from beside opening to the only downspout. After clearing the clog there was still some standing water right beside the downspout. It looks like the roof was previously treated with some kind of elastomeric coating. That coating is badly degraded in several areas but because the interior ceilings show no evidence of water I suspect (hope) those deteriorated spots (like in 2nd & 3rd photos) were not the source of the leak. Also, joints between sections of the perimeter wall cap are starting the separate (4th photo) and nails under mastic on top of the cap are starting to be exposed (5th photo).

At minimum, some maintenance is needed on deteriorated spots. It appears impossible to hire a roofer right now. Three I called said they are only doing replacements, no repairs. Whether for spot repairs or recoating the entire surface, do you recommend silicone or acrylic based elastomeric coating? Something else? For joints between wall cap segments, and to re-cover nails, is something like Henry's Wet Patch OK or should I use something else? Thanks.

 

[Snoonyb]

Flat roofs will naturally drain, and whoever installed the metal in photo #2, created a pond.

 

[nobes]

We had a massive, much needed rainstorm a couple weeks ago but the downspout for the flat-roofed section of my mother-in-laws house clogged, the roof flooded and water leaked into the exterior wall of one bedroom. I suspect the water got deep enough that it simply over-topped the edge of the roof barrier. However, it is clear there is enough damage that serious maintenance is needed. The first photo below was taken from beside opening to the only downspout. After clearing the clog there was still some standing water right beside the downspout. It looks like the roof was previously treated with some kind of elastomeric coating. That coating is badly degraded in several areas but because the interior ceilings show no evidence of water I suspect (hope) those deteriorated spots (like in 2nd & 3rd photos) were not the source of the leak. Also, joints between sections of the perimeter wall cap are starting the separate (4th photo) and nails under mastic on top of the cap are starting to be exposed (5th photo).

At minimum, some maintenance is needed on deteriorated spots. It appears impossible to hire a roofer right now. Three I called said they are only doing replacements, no repairs. Whether for spot repairs or recoating the entire surface, do you recommend silicone or acrylic based elastomeric coating throigh peachtreerestorations.com? Something else? For joints between wall cap segments, and to re-cover nails, is something like Henry's Wet Patch OK or should I use something else? Thanks.

On a garden room project I've got a flat cold roof (75mm slope across 3.5m). For soffits there is an overhang on the high side of 500mm and on the low side about 100mm. The joinery is 2x7s stuffed with 140mm of PIR. Providing quite a bit of air space under the osb which sits atop the furring. What's the normal way of providing ventilation to the roof cavity? Soffit vents on the low side and fascia vents on the fascia of the high side? Or are soffit vents either side ok? Or can I reverse so that I have soffit vents on the high side and fascia vents on the low? Aesthetically venting on the fascia of the high side would be least good. Is it normal to have mesh on the inside of the vents to protect against critters? If so what's the advised density for the mesh? Those I've seen would definitely let through wasps who seem to like to nest everywhere. And the soffit vents that I see on typical pvc boards look big enough to accept hornets. Thanks in advance!

 

[tomtheelder2020]

On a garden room project I've got a flat cold roof (75mm slope across 3.5m) ....

Nobes, my post you commented on is over 2 years old. You are much more likely to get responses if you start a new thread. Pictures are also much more likely to garner responses. Imperial units would too.