Flat Roof Extension Leaking But It's Not The Roof

[thomp1983]

Hi,

Our rear flat roofed extension developed a small leak on Tuesday. On Tuesday the rain was directly from the south which is very unusual and I noticed a small leak whilst working in the extension.

Had a chance to look at it today and what's actually happening is, we have white upvc shiplap cladding, this has shrunk slightly in the cold weather leaving a small vertical gap (2mm) between 2 of the boards.

Heavy rain from the south manages to get into this gap, it then runs down the plastic sheeting behind the cladding, behind the epdm which is lapped up behind the bottom piece of cladding but is only bonded to the batton holding the bottom board.

Short term option is to fill/cover the gap, I'd assume some sort of flexible sealant will fill the gap but what will happen to it in the summer when the boards try to expand again?

Long term I think the bottom rows of cladding should be removed and the plastic sheet rearranged so any run off from it laps onto the epdm, I think this should of been done by the roofer in the first place?

Thanks
Chris

 

[freddiemercurystwin]

Yes the plastic sheeting behind the cladding should lap over the top of the epdm upstand allowing any water that gets through the upvc cladding to drain from the cavity behind the cladding. The cladding is not designed to be 100% waterproof.

 

[datarebal]

Cladding sounds wonky , but certainly the epdm should extend up under any underlay behind the cladding