Breather membrane leaking

[Tweedledee]

We have a 16 degree pitch roof on a new extension. The roofer has so far installed Jewson breather membrane and battens. Concrete tiles to be fitted later.

One visible small hole is visible in the membrane. In addition during rain over the long weekend, three or four spots have let water in, one drip is more than just "spotting" too.

Is the membrane no good and should be redone, or is this adequate?

Before the work I'd asked the builder about having double membrane and he said we didn't need it.

Thanks.

Dave

 

[freddiemercurystwin]

The membrane is essentially the backup should the tiles ever leak and will stop a lot of dust in the air entering the loft, its not sealed just lapped so anything other than perfectly calm conditions will allow it to leak a bit though. Theoretically it should provide protection to the loft in the period between the membrane going on and the tiles but bear in mind its been penetrated about 10,000 times though. There should be no holes or areas you can see light through though so any patches should be addressed prior to tiling. Hope your tiles are suitable for a 16° pitch.

 

[Tweedledee]

The membrane is essentially the backup should the tiles ever leak and will stop a lot of dust in the air entering the loft, its not sealed just lapped so anything other than perfectly calm conditions will allow it to leak a bit though. Theoretically it should provide protection to the loft in the period between the membrane going on and the tiles but bear in mind its been penetrated about 10,000 times though. There should be no holes or areas you can see light through though so any patches should be addressed prior to tiling. Hope your tiles are suitable for a 16° pitch.

Thanks for the response, and I understand it's a backup to the tiles.

Still, after more rain it leaks in about 10 places and I can see daylight in about five places now through small tears, perhaps due to being blown about a bit since last time. As a system I don't really understand how good a backup it is when it is really quite leaky itself.

We have ordered tiles good down to 15 degrees thanks. Not yet fitted of course.

 

[freddiemercurystwin]

Thanks for the response, and I understand it's a backup to the tiles.

Still, after more rain it leaks in about 10 places and I can see daylight in about five places now through small tears, perhaps due to being blown about a bit since last time. As a system I don't really understand how good a backup it is when it is really quite leaky itself.

Well ordinarily it would have tiles on it so not really subjected to any high winds or driving rain as it is at the moment. Ordinarily, once the tiles are on all it has to do is to enable the odd trickle of water that does get through the tiles to run down to the gutter or if a tile slips for instance. If anything more than the odd trickle now and then gets through the tiles they are not installed properly or are unsuitable. But as mentioned any tears or holes should be properly repaired before tiling.

 

[^woody^]

The membrane should be waterproof ie resist any water penetration behind the tiles.

It should also be lapped sufficiently to deal with low pitches

Any rips or tears will be a potential point for water to get in, and that is where a higher quality product becomes useful as it resists tears a lot better ...... especially in conjunction with less skilled roofers or those which just do not care

However, once the tiles are fitted, then the membrane wont be exposed and so wont get anywhere near the amount of water it is getting now - if any at all

 

[noseall]

Your roof tiles are your weathering layer, though a leaky membrane full of holes displays a rather lackluster installer.

 

[Tweedledee]

The builder has been back and doesn't even think that the holes need patching up.

I think I'm going to have to patch up the holes myself with gaffer tape.

Still, I'm wondering if there is a self-healing membrane on the market, as a leaky "insurance" is unimpressive.

Dave

PS We've had a stall on the job waiting for bifold doors to arrive, and I am surprised the builder didn't just put the roof on as it's been three weeks or so, although the floor is concrete.

He now wants to knock through from the new extension into the main part of the house before roofing, as he says the knocking through could affect the roof.