New roof looks dodgy?

[AK501]

Hi friends!
My roofer just completed my new roof with new battens and breathable membrane. The membrane is taut in some places but slack in others. Is this normal or a sign of bad workmanship?
Thanks

 

[noseall]

Hi friends!
My roofer just completed my new roof with new battens and breathable membrane. The membrane is taut in some places but slack in others. Is this normal or a sign of bad workmanship?
Thanks

Its meant to be slack.

 

[AK501]

Thanks. So is the work done in the photo normal and not bad workmanship? Thanks

 

[stevie888]

It should dish so bad wormanship strictly, but it is very very common to see. BC typically don't stress about this.

 

[noseall]

Thanks. So is the work done in the photo normal and not bad workmanship? Thanks

It can be difficult to actually get the fabric to sag, especially on drafty day. It's not high up on the agenda no.

 

[AK501]

Thanks all. I just had a chat with my roofer who insists it’s meant to be like that to avoid tearing and support airflow.

 

[freddiemercurystwin]

Thanks all. I just had a chat with my roofer who insists it’s meant to be like that to avoid tearing and support airflow.

It's supposed to sag so as to ensure there's a physical gap between the membrane and the tile battens to ensure any rainwater that gets through the tiles can flow freely down the roof slope and into the gutters.

 

[^woody^]

I can't think of any demonstrable instance when membrane fitted taught has not performed.

Personally, having seen many roof voids with membrane, including those going back to when membrane became popular, I don't recall seeing any roof issues where membrane was fitted taught.

I can't see how the membrane performs differently, and more pertinent detrimentally if fitted taught. It still breathes and it still keeps water out.

I suspect that one of the reasons if not the main reason, relates to the the ease at which the material tears. And similar stress around the staple fixings - leading to risk of puncture and water ingress. But that's an issue with installation not afterwards.

It's interesting to note that the same membrane fitted vertically on timber frames, is fitted taught.

 

[Scally-Ho]

All this modern talk of membrane had me wondering what was being discussed, and then I sussed it, it was sarking felt for a roof and then it all fell into place. I had visions of a 'virgin' roof awaiting the big break-through

 

[AK501]

Thanks guys - I really appreciate it!

I've got to make payment for the roof next week. Is there anything I should check or challenge the roofer on before completion? Only reason I'm concerned is because he subcontracted the work and a bunch of lads got the whole thing done in a day!

Attached are some more photos if that helps. Thanks again.

 

[catlad]

Its going to be poor if he did it in the day.

 

[catlad]

I can't think of any demonstrable instance when membrane fitted taught has not performed.

I can, leaks occur and batons rot quicker. Unlike slate roofs, tiled roofs let water past onto the membrane in extreme conditions, this is then supposed to drain harmlessly into the gutter if the felt has the recommended dips between the rafters.

 

[Notch7]

I can, leaks occur and baton rot quicker. Unlike slate roofs, tiled roofs let water past onto the membrane in extreme conditions, this is then supposed to drain harmlessly into the gutter if the felt has the recommended dips between the rafters.

I was wondering how the roof membrane is fitted loose in practical terms.

my guess is that you roll out the membrane across the roof then work across stapling a rafter at a time, pulling a bit of slack into each section as you go.

 

[freddiemercurystwin]

Like a proper tradesmen taking his time you mean?

 

[freddiemercurystwin]

It's interesting to note that the same membrane fitted vertically on timber frames, is fitted taught.

That's because there's a ventilation gap (or should be) in a vertical situation so it doesn't matter if it's taught.