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Roofing

New roof leaking above valley area

Anonymous user 03/03/2024 - 3.27 PM

Have had complete new roof using clay interlocking tiles that go down to 17.5 degrees Roof pitch 21.5 degrees Water ingress on top of one rafter above roof/porch valley during prolonged periods of rain. (Valley quite short - under 2 metres) The total width of lead is about 45 cm. There is membrane under the lead and membrane from roof over the lead each side of lead The tiles overlap each side of lead leaving an open valley of approx 4-6 inches Dampness creeps up the top of rafter a few inches the more prolonged the rain. Membrane damp also Have photos - not sure how to attach to this question? The tiles are mortared in the valley area Valley is new lead Have done hose test in area and above for 1 hour to check if water is entering from elsewhere on roof but no result Any ideas

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4 Answers

Stephen Watson

Rating: 5 out of 5

Horsham

possible leak above coming down on felt under tiles or valley does not have enough fall. How long is the valley? Was it put up and under enough with felt over? Best answer is to strip out and check. Sometimes having the tiles mortared in the valley can cause problems.

Answered11 February 2020

All Trades Fitting Company

Rating: 4.7 out of 5

Perth

Hi. Sounds like the valley mortar is cracked or the valley tiles don’t have enough cover. If the valley is lead and the pitch is shallow chances are there is a bit of capillary action between the lead and the mortar. I never recommend mortar onto a lead valley as lead moves and mortar is not flexible. Strip out and redo the valley with the correct overhang and replace lead with grp valley. Hope you get it sorted cost effectively.

Answered11 February 2020

KSW Roofing & Plastering

Rating: 5 out of 5

Stafford

It’s a new roof... there should be no leaks, period. It obviously has been installed incorrectly. Valleys.... should have the breather membrane (valley sheet) installed under whatever is being fitted First, spanning 500-600 mm either side of the valley. Lead valleys aren’t ideal for a mortar finish as lead moves so it’s prone to crack. He May have not left an adequate overlap on the tiles... Call the tradesman back too put it right. It. It should have a workmanship guarantee at the very least.

Answered15 February 2020

Congreve Roofing Limited

Rating: 5 out of 5

Stafford

Have the roof tiles been laid at the correct gauge ? If there are tile courses running across the top of the valley, I would check for broken underside lap interlocks, one or two of these will allow ingress. Have the tiles been cut neatly and fully in the valley, not missing small cut that are filled with mortar. Does the Lead Valley have a welt or raised section at the ends to stop water spilling over. Has the valley pointing over filled the valley, forcing any water to spill over the edge of the valley.

Answered17 February 2020