Flat roof meeting pitched leaking.

[Dav657]

We have a leak inside at the beam where our extention flat roof begins.
Outside the flat roof meets a pitched tiled roof, with dormer.
Rain water somewhere is getting beneath the tiles at the side of the dormer wall cladding.
This is running over the roofing felt and as this felt goes beneath the rubber flat roof covering upturn, which is around an inch higher, than the felt beneath. The rain water is dripping from the end of the felt and working its way down the beam side plasterboard and through a crack that has opened up in our kitchen.
Ive moved the tiles up to inspect, surely this is an error when the extention was built around 34 years ago.
Shouldn't all the under tile felt go over the flat roof upturn so that any rain water getting under the tiles would simply run down on to the top of the flat roof covering?

 

[bobasd]

OP,
why not post detailed pics of all the details you mention - and stand back context photos so we can get a general grasp of things.

 

[Dav657]

I've dine a drawing (not to scale)
It shows the rain water flow running over the roofing felt and down the loose hanging end into the plasterboard lining the beam.
Note the 1 inch gap that the water runs through between the felt and the thin board with the rubber flat roof covering inclining up beneath the tile. Surely that 1 inch gap shouldn't be there or at least the felt should be riding over it on top of the rubber covering?

 

[Vinty]

Relying on the underfelt to keep the rain out is only a temporary solution.
There must be a leak on your tiled roof which is causing the rain to run down the underfelt and into the room below.
The underfelt should be riding over the top of the rubber upstand on the flat roof.
First you have to find and repair the source of the leak on the pitched roof and then strip back the eaves tile courses and bring the underfelt over the top of the rubber on the layboard of the flat roof.

 

[Dav657]

Thank you very much. Yes I need to trace the leak. It seemed strange that they would run the felt beneath the layboard, thus causing the water ingress inside our property. Thanks again.

 

[Notch7]

I've dine a drawing (not to scale)
It shows the rain water flow running over the roofing felt and down the loose hanging end into the plasterboard lining the beam.
Note the 1 inch gap that the water runs through between the felt and the thin board with the rubber flat roof covering inclining up beneath the tile. Surely that 1 inch gap shouldn't be there or at least the felt should be riding over it on top of the rubber covering?

Probably the tiles shouldve been stripped back further and the epdm run up the pitch more, then tiles dressed back over.

 

[Vinty]

Thank you very much. Yes I need to trace the leak. It seemed strange that they would run the felt beneath the layboard, thus causing the water ingress inside our property. Thanks again.

Could be something simple like a cracked roof tile, who ever did the original flat roof should have ensured that the underfelt was dressed over the top of the rubber on the layboard, any water running down the underfelt would then run onto the flat roof instead of into the room below.

 

[bobasd]

Notch7, i'd go with your observation that the EPDM should have had an upstand.

OP, why not go on the flat roof and strip back a few tiles from the bottom three courses (perhaps you've previously opened the roof up?), and photo it and post on here?

it might be possible to fix an upstand, re-jig the bottom courses & install a plastic eaves tray, or similar, & then bring the felt down over it?
google pics of felt support trays and eave trays.

 

[Dav657]

Sorry for delay. Thank you for all comments.
I stripped the plasterboard from the underside (inside) in our sons bedroom from the sloping pitched roof area next to the dormer, as there was a damp patch at the section.
Strangely there was a cut out in the lead flashing and I could see daylight. This cut out was right down to where the flashing starts to bend up to go behind the cladding.
With the amount of rain we had, had a lot of silt and debris had been flushed of the flat roof creating a sort of dam and diverting some of the dormer roof rain water through this cut out onto the felt causing the leak that ended up in our kitchen ceiling beam. The timbers were soaking as some water had also run down them causing the damp area in the bedroom.
Well all fixed now, the roofer has built a slope, with a rubber covering and gutter system that covers the flashing.

 

[noseall]

Thank you very much. Yes I need to trace the leak. It seemed strange that they would run the felt beneath the layboard, thus causing the water ingress inside our property. Thanks again.

Winkers!

Lazy winkers at that. You have had a cowboy job done by a chancer. The felt is important especially if you have concrete interlocking tiles. It should be dressed over the cocking fillet which should be fixed to the layboard.

 

[Dav657]

Yeah cowboy job building the extension which the previous owner's had done. We discovered several faults after moving in, although this one had taken 34 years to show.
Others included not tying in roofing joists at walls causing gaps to open up during cold weather, brickwork untidy and placing fillets to make up the gaps but some bricks that close hardly any mortar. Cheap floor boardings causing them to sag between joists. Wide vertical crack appearing behind main radiator, lack of light switches etc.