Roof

[col72]

Got a broken roof tile been meaning to get it fixed we have had some nasty weather past few days so went in to loft to check noticed where broken tile is rain has come through the membrane this has not happened any other time it has rained could the gale force wind forced the water through it has always been dry till this bad spell of weather

[The Builder]

Just a guess, col, but it's very unlikely to have water come through the felt.
What is very common though, especially in strong winds, is for water to be blown between the "lap".

i.e. where one layer of felt laps over the one below. Old felt widths were about 900mm (3'). Newer felts are around 15mm (5'). So there are plenty of laps.

I had one recently where I had to advise stripping the roof section and re-felting because the laps were only a few millimetres rather than the conventional 100mm (4").

Even with a proper 100mm lap, gales can occasionally lift the lap enough to let water blow in. It's often evident when the loft fills with snow.

[col72]

It's leaking on a roof beam don't think there is a lap near it just started when we had gales and rain

[The Builder]

Water travels along beams, col. It can show up some distance from the leak. Especially with the wind behind it.

Unless the membrane is torn, water won't get through it. I really can't think of any other reason, I'm afraid. Maybe you've lost, or dislodged a ridge tile?

Tiles or slates?
If tiles - concrete or clay?

[col72]

Concrete I think it's leaking right whet the tile is snapped can't see any tears like I say it's leaking on top of beam half way down

[The Builder]

If you're sure there is no tear at that spot, then there's one more possibility. If it's right on a rafter ....... then it sometimes happens that driven water will get in through the nail hole where the batten is nailed (through the felt).

I've had that before.

Old-fashioned bitumen felt or modern microweave?

[col72]

Modern stuff

[boxtops]

I've had that happen, builder - under extreme weather, rain appeared in our bathroom, our builder said there was a nail through the flashing by the window. Never happened before or after, just under certain weather conditions.

[The Builder]

Yep, that can happen, Boxers. I guess it's a nail hole. Old-fashioned bitumen felt was sort of self-sealing around a nail hole because of its soft, tarry nature.

Modern felts, although breathable and far superior, don't have that property.

It only comes to light when a tile is missing, and is subject to wind-driven rain.

[col72]

Builder you any idea how much I should be looking at to strip 1 side of the roof refelt and put old tiles back on its a 3 bedroom semi