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Damp Proofing

Blistering render below fascias and guttering of a flat roof

Anonymous user 28/02/2024 - 3.56 PM

We've got severe blistering of paintwork and render just below uPVC fascia and gutter on extension (flat roof). The render beneath the paintwork is so soft due to the amount of moisture in it and it's just dropping off. Can't understand where the water ingress can be coming from. Nothing showing internally. Felting hangs down into gutter (but not so far to rest in rainwater) so can't see how it could get behind the gutter and fascia.

Are you a tradesperson and able to answer this question?

3 Answers

Anonymous user

If the felt isn’t folded and stuck together to form the drips then the water can climb back up which is called capillary reaction causing it to penetrate behind the render.
Answered9 January 2021
1

Anonymous user

Its a flat roof...Why is there any felting hanging into the gutter? A tiled roof would have Tyvek that can hang into the gutter sometimes when its not been trimmed correctly. But a flat roof should be stuck down and the gutter should be below the stuck down felt and there should be 20mm gap due to the clips. If the felt is hanging off your flat roof, then it needs replacing or repairing as water is driving underneath when the wind is up. But your felt should not be in your gutters at all. If you are going to replace the flat roof I would however recommend going with fibre glass. Less hassle.
Answered27 January 2021
0

Anonymous user

You need to look into getting eves trays fitted as most builders will use felt and it will shrink back over time and allow water to get between the gutters and the fascia
Answered4 February 2021
0