Ponding Water on Flat Roof - Build Up With Cold Process Modified Bitumen SA
Dealing with ponding water on a modified bitumen granulated flat roof is essential to get the life out of the material. Even when using self-adhered modified bitumen systems, when adhering to granulated surfaces, it is important to use adhesive. Sure you can prime it and stick it down, but it does not bond and seal. It will only seal if there is adhesive used.
The rule of thumb for ponding water on modified bitumen systems is 48 hours. If the area does not dry up within 48 hours, then it is ponding and must be dealt with.
With self-adhered systems, ponding water can literally eat away at the material. In this case I used layers of modified bitumen strategically placed to build up the low area to hold almost no water. By the time I finished, the water was enough that it would easily dry up in a few hours.
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Пікірлер: 17
Thank you. I have a spot on my flat roof about that exact size that retains water. This is exactly what I've been looking for to avoid paying for a new roof. Going to give it a try.
@PracticalRoofingConcepts
7 жыл бұрын
Definitely will be if that is all that is wrong!
Wow, lot of labor!
@PracticalRoofingConcepts
5 ай бұрын
Special project
Looks good, ever thought of using roof leveler mix?
@PracticalRoofingConcepts
3 жыл бұрын
It was a new install (warranty) and I wanted to make sure the finished product was still granulated modified. I also wanted to stay with like materials. If it was a new call and this was the complaint, then I may have applied a coating product to remove the low spot.
Aerosol spray paint can be used to mark the ponding edges.
@PracticalRoofingConcepts
5 жыл бұрын
Yes, most likely, but crayon will stick when wet.
We have a number of older homes in the local market with flat roof "ponding" ( US Western Penna) and the problem is significant as you show with a bitumen surface. it ALSO deteriorates an EPDM commercial surface but not as quickly. your approach was quite detailed. my suggestion is to have home roofs designed with some slope but architects seem otherwise oriented. bad karma!
@PracticalRoofingConcepts
5 жыл бұрын
This is how to get through an existing situation. Usually we can add tapered insulation to add some slope, but for some reason this one did not work out as planned. So this was the answer to keep water from standing.
Looks great, did you sprinkle white granules along the edges?
@PracticalRoofingConcepts
4 жыл бұрын
No, but I don't think I had much bleed out.
Thanks a lot for the video. Where can we get the sheet you put on? What adhesive do you use, is it a kind of tar?
@PracticalRoofingConcepts
5 жыл бұрын
It is called Modfied bitumen Granulated cap sheet. The reason I used the self adhered in this video is I am using "like" materials, as the existing flat roof is a self adhered material (Certainteed SA Cap). There is a cold process version or Mop Grade. The adhesive is either Modified Roofing Cement(Trowel Grade) or Modified Roofing Adhesive (brush grade) - check out this video kzread.info/dash/bejne/qqFqxreSganMd8Y.html - kzread.info/dash/bejne/faNkzc1qea6rgNY.html
@talk2stars
5 жыл бұрын
Thanks a lot for the reply. My roof has a one-inch deep pond of ~4 sq feet near the drain. I saw you put on a few layers of the cap sheet over a few weeks in the video. Can I coat a few layers of this cap sheet with bitumen in between within one day?
@PracticalRoofingConcepts
5 жыл бұрын
I am always wanting the layers to cure out. That is why I only did a layer at a time. It really doesn't matter what your doing, it has to cure or the bottom layer will never cure. This is the method used without tearing off and is pretty solid. All it is doing is displacing water. The standing water will eventually wear away the material in that spot.
@talk2stars
5 жыл бұрын
got it, thanks a lot!