ᐅ Is a flat roof without any slope okay? Won’t water just pool on it?
Created on: 23 Sep 2018 21:21
D
Doublebubble
Hello,
for our extension (timber frame construction), a flat roof with tapered insulation was planned. Later, the architect decided not to include the tapered insulation. Now the roof is finished and constructed as a “zero-slope roof.” After it rains, water pools extensively in the center to about 2 cm (0.8 inches) deep, even though overflow outlets are planned on two edges of the roof. The water eventually evaporates, leaving typical dirt marks, which looks unpleasant since the upper floor has a direct view of this area.
The architect says the roof is fine, that a zero-slope roof is allowed, and that standing water on the roof is not a problem.
I am now wondering, especially since this is a timber structure, how long such a roof will last or whether this design might even be non-compliant.
for our extension (timber frame construction), a flat roof with tapered insulation was planned. Later, the architect decided not to include the tapered insulation. Now the roof is finished and constructed as a “zero-slope roof.” After it rains, water pools extensively in the center to about 2 cm (0.8 inches) deep, even though overflow outlets are planned on two edges of the roof. The water eventually evaporates, leaving typical dirt marks, which looks unpleasant since the upper floor has a direct view of this area.
The architect says the roof is fine, that a zero-slope roof is allowed, and that standing water on the roof is not a problem.
I am now wondering, especially since this is a timber structure, how long such a roof will last or whether this design might even be non-compliant.
D
Doublebubble12 Jun 2019 13:53Hello everyone, a brief update. Completion of the renovation, moving in, fixing various defects, family growth... there was quite a bit to do, which is why I’m only getting back to you now.
Thanks for your replies!
First of all, no agreement has been reached with the architect yet, because all of his remaining trades had to complete their work first.
You wanted to know how the flat roof came about.
Originally, a slope of 2% was planned. A higher slope wasn’t really possible, as the parapet wasn’t sufficient. I don’t know why, since the architect initially had complete design freedom.
When the timber frame of the extension was up, during a site meeting (you always discuss a huge amount at such meetings), I was told, among other things, that smaller water puddles would remain on the roof due to the seams in the bitumen membranes.
Further discussion then focused on options for installing decking or gravel on the roof, since the ugly black roof was clearly visible from the first floor.
And then suddenly, without new drawings or explicit approval, or warnings about potentially increased maintenance, the roof and the water level on it were just like that...
Thanks for your replies!
First of all, no agreement has been reached with the architect yet, because all of his remaining trades had to complete their work first.
You wanted to know how the flat roof came about.
Originally, a slope of 2% was planned. A higher slope wasn’t really possible, as the parapet wasn’t sufficient. I don’t know why, since the architect initially had complete design freedom.
When the timber frame of the extension was up, during a site meeting (you always discuss a huge amount at such meetings), I was told, among other things, that smaller water puddles would remain on the roof due to the seams in the bitumen membranes.
Further discussion then focused on options for installing decking or gravel on the roof, since the ugly black roof was clearly visible from the first floor.
And then suddenly, without new drawings or explicit approval, or warnings about potentially increased maintenance, the roof and the water level on it were just like that...
H
HilfeHilfe12 Jun 2019 16:45The roof of our storage rooms was also greened because we had standing water. However, it was a small area. It is a matter of structural engineering and cost. The soil absorbs the water.
H
hampshire12 Jun 2019 19:29I wouldn’t wait until everything is finished, nor immediately confront the architect.
Ask neutrally how the difference from the original plan came about. If the answer is vague, keep asking (when, which meeting, who was involved, is there a record…). If it turns out it “somehow happened,” request a solution—without assigning blame—that ensures the water drains as originally planned. If someone explains why that’s not possible, don’t argue; instead, steer the conversation back to solution-oriented thinking. Ask, “What alternatives could work?” or “Which other solution would be feasible?”
This approach helps you get closer to achieving a roof with the correct slope without extra costs or conflict.
Ask neutrally how the difference from the original plan came about. If the answer is vague, keep asking (when, which meeting, who was involved, is there a record…). If it turns out it “somehow happened,” request a solution—without assigning blame—that ensures the water drains as originally planned. If someone explains why that’s not possible, don’t argue; instead, steer the conversation back to solution-oriented thinking. Ask, “What alternatives could work?” or “Which other solution would be feasible?”
This approach helps you get closer to achieving a roof with the correct slope without extra costs or conflict.
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