Water leak

No reason, it can stop the whole sheet of plasterboard sagging down and needing replacing, later use one of those handy LidALdi dead-man props and a sheet of metal to hold it back up and dry flat.

No problem at all The plasterboard is presumably totally ruined already and will need patching and decorating anyway.

I had the same problem with an upstairs bathroom leaking downstairs. But it ended up making a new hole in the plasterboard repair anyway.

I'll patch that when I've finished sorting out the bathroom!

Good enough, ta.

I have a valley gutter where two pitched roofs meet at right angles. Shortly after I moved in, this started leaking. The valley was constricted of planks (actually floor boards), lined with lead. After years of expanding and contracting in the heat, the lead creases and cracks, hence the leak. Next door but one in the same terrace was a builder who taught repair work of older buildings, and did some himself too, in addition to building himself a new house at weekends. I got him to replace the gutter, which he did by replacing the lead with a GRP liner. In the loft, you could see bits of daylight through the gutter now which was a bit alarming, but that's because the GRP was clear, not because there was any hole through.

About 20 years later, it started leaking again, but this time the cause was different. A few tiles further up the roof had cracked resulting in some water running down the lining paper. Eventually, this rotted through where the lining paper made contact with the valley gutter, and ran inside the roof. I decided to do this myself. I stripped the roof back to the rafters 1-2m either side of the valley. Fitted modern felt and new battens, and laid the tiles back on, replacing the broken ones. Got it all done just before a tremendous downpour, and although I hadn't repointed the valley at that point, nothing came through. (If the rain is vertical, the pointing isn't required - it's only required to cope with diagonal rain due to wind.) I couldn't actually see how to do the pointing, so I got a roofer who was working up the road to come and do it. It was interesting watching how to do it, but it wasn't a neat job, so as soon as he'd gone and before the mortar set, I pulled it all out and did it again! To help prevent such leaks again, I temporarily removed the bottom two rows of tiles all the way around the house and fitted felt support tray before relaying the tiles. Also replaced the facias and gutters. That was 20 years ago, and it's been fine ever since.

Andrew

When my flat roof started leaking a couple of years ago, I made a few holes in the plasterboard ceiling, put a small screw into the ceiling right next to the hole, then tied a length of string to the screw, with the other end of the string in a bucket. The water then just runs down the string and into the bucket without any splashing. The bucket didn't need to be directly under the hole, so I could have multiple strings (from other holes) discharging into one bucket. Works better if you dampen the string first.

Ah, now there's posh!

Of course that pre supposes the leak is directly above your hole. If its plasterboard or something like that, then be careful I did this in the corner of my bedroom some years ago, and a huge mass of soggy plaster fell on my head. Brian