Then we noticed the edges of the wallpaper starting to curl, then a few days later...
Wallpaper trying to fall off the wall and being saved by a picture of a 2CV. You can't see the 2CV, it's busy saving the wallpaper.
Ah, maybe this is a problem that I need to deal with. Since this is around the chimney, we assumed that the problem would be with the lead flashing around the chimney stack, but the only way to find out was to go up there and have a look. If the chimney had been on the conservatory side of the house, that would be relatively easy, but it's not, it's on the driveway side. Luckily, our friend Jasper was happy to lend us his scaffolding tower and roof ladder.
Our neighbour suggested going into the loft to see whether there was moisture on the surface of the chimney breast up there, but after a bit of thought I decided that I'd rather go up on the roof. I hate rockwool insulation (loathe and detest) a lot more than I hate heights (not at all).
I would like to be able to show you a photo of what I found up there but my phone battery chose this time to give up the ghost, Ian refused to lend me his Blackberry, and I didn't want to carry a camera that I couldn't fit in my pocket, so you'll have to make do with a description. I found plenty of evidence for what the neighbours had told me, namely that this has been a problem for a long time - ever since the extension was built in fact.
There was plasticky sealant slathered over every conceivable gap in the brickwork, including the joins between the flashing and the chimney. It had been applied so liberally that it stood proud of the brickwork. This meant that one small fault in its adherence to the wall would allow water to flow down between the sealant and the brick, and be channeled into the gap between the bricks. I pulled a small piece out and confirmed that this was exactly what had happened - it was soaking wet and covered in moss.
Problem identified (well, a problem identified), I needed guidance on how to fix it. I consulted my trusty Readers Digest DIY manual, which had helpful instructions on how to fix various faults with flashing, including repairing the mortar where the flashing joins the brickwork, and where it's appropriate to use sealant (not in place of mortar).
We set off to buy some mortar which, since it was Sunday morning by this time, meant B&Q. By far the cheapest option per quantity of mortar would be to buy the ingredients and mix it up ourselves, but since we only needed a little and cement has a very short shelf life we went for the 'just add water' kind, though I very nearly walked out of the shop in disgust at the cutesy instructions -
Reach your right hand over your left shoulder and give yourself a hearty pat on the back.Ugh!
Having survived B&Q (which wasn't nearly as bad as it can be. The staff at the Aberystwyth branch were very friendly and helpful), I didn't manage to steel myself to get up on the roof again on Sunday (though there was some faffing about with phones and old cameras). Yesterday the weather was clear and dry so I really had no excuse. I went up in the morning to pick off all the old sealant, then again in the afternoon to insert mortar into places where there should be mortar. The second time I took a bottle brush to clear out all the moss. I've never done pointing before - where better to learn than on a chimney?
I might add that I only did one side of the chimney and the 'uphill' face as the downhill face didn't need work and I didn't think it was worth moving the ladder to get at the other side when any water that gets in there will end up a long way from the surface of the wall as it's between the old building and the extension. OK, that's not a very good argument, but it would be as much work again to do the other side and I'm not convinced it's necessary.
Even after applying the mortar, the job wasn't quite finished. I'd bent some of the lead away from the bricks so I could get at the mortar gaps behind it, then wasn't sure what to do with them afterwards. It seemed wrong to fill a gap with wet stuff then immediately cover it up with a waterproof sheet, but on the other hand, how long does mortar take to dry? I couldn't leave them sticking out for weeks, so I compromised and left it overnight, in which time it hailed three times.
This morning, I went up again to put the lead flashing back in place, and to clear up the mess. I had dropped rather a lot of mortar all over the roof. Ian was out so I let the neighbours know what I was doing. They promised to listen out for a scream. In spite of the wooden boards now being wet and slippery, that task passed uneventfully and I was able to assure the neighbours that they wouldn't need to call an ambulance after all. All that remained was to take down the ladder and scaffolding, which was a two person job, so I had to wait for Ian to get home.
I just broke off from blogging to catch a break between hail showers and go and do that. We were just manhandling the ladder down to the ground when it hailed again. Meanwhile, with all that climbing up and down a wobbly scaffolding tower (never mind the roof ladder - that tower is the scary bit), the muscles in my legs were aching and getting pretty wobbly too. At one point I was standing on a slippery board with wobbly legs, high enough to look into our upstairs window, and realised I'd have to sit down on that freezing, wet board for safety's sake. This part of the job was not fun.
Still, the job is now done and we can return Jasper's ladder and scaffolding. I feel quite pleased with myself, but it would be nice to know whether I've actually solved the damp problem. I guess I'll just have to wait and see.