johncrowther

Verne, You are a font of knowledge; thanks for replying! The mortar stuff seems to be all over the top of the insulation, and there are bits hanging from the inside of the roof, waiting to drop. So my impression is that the inside of the roof used to be covered in this mortar stuff, presumably to hold the tiles on to the batons. It would appear, as things stand, that the roof is doing ok without this mortar stuff in place, but I don't want to tempt fate. I'm not sure why there is so much of it in that corner; perhaps the same person who rolled back the insulation from that rectangular strip chucked it all there as it was in his way? I would be very surprised if that roof isn't original. The house is just over 100 years old and the roof looks like others in the street (apart from those that have been re-roofed with concrete tiles.) The house to the left of mine has some sort of black grease spread all over its roof so that might give a misleading impression - I can see what you mean; their black grease makes their roof look different. If those white things are for old aerials then presumably the wooden frame has been in situ since the house was built. The straw stuff is only in one corner and near to it, on the brick (the top of the external wall) there is what looks like bird droppings, hence my presumption that it could be bats. I agree.. I need to have a nose round up there when it is pouring down outside. Radiator is working in the spare room now and I had it on full blast yesterday with the dehumidifer on. The wall looks a hell of a lot drier with only stain indicating where there was previously water. The ceiling has also dried. So my plan now is to repaint the room and continue keeping it warm with dehumidifier on every other day, and window on the latch when ever somebody spends any time in there. If the damp patches re-appear then I think I may need some pointing doing, or roof work. Thanks again

Ok, I've taken a load of pictures. I've started to have a different impression about what the problem is, having climbed into the attic and taken a load of photos of the house. Haven't been up there since I moved in nearly 3 years ago. I started out thinking there was a leak in the roof causing a damp patch in the spare room ceiling and water to get in down spare room (outer) wall. I also thought the wall aspect could be due to pointing. But I'm now starting to think it is a condensation problem as the radiator in that room doesn't work (it will do from tomorrow) and we dry a lot of clothes in doors at this time of the year (so I think maybe a lot of moisture in the house migrates to that cold room.) I would be grateful if people could look through these pics and my comments and offer some advice if possible (the story involves the sub plot of bats in the attic and a s**t load of broken off mortar stuff....) 1) So here is the suspiciously regular shape of the ceiling's damp patch. 2) And here is the damp on the wall of the same room. Some patches near to the top of the wall, just under the cornice result in small dribbles emanating from them that run down. 3) Here is a pic of the outside of the house (the spare room relates to the window on the left). There is the odd wonky slate here and there but nothing too horrific. 4) Now inside the attic I can see the reason for the bizarrely regular rectangle shape of the damp patch. The insulation has been rolled back from that area. I have since rolled it back over. 5) Here is a general view of that part of the roof followed by a pic of the front side of the roof (which doesn't seem to have any problems.) 6) Here is the corner near to where the main damp patch appears on the wall - seems to involve droppings, straw and a s**t load of mortar stuff that has dropped off. As well as some hanging things that look bat related. 7) Some kind of toilet tissue looking stuff (?) 8 ) Some kind of white little spores on the wood. 9) The underside of the slates, missing the mortar stuff that has all fallen on to the top of the insulation. I'm assuming the insulation has been in for 25 years or less (that's a guess), so it seems odd that all of the mortar stuff has fallen down since that time. - seeing as it is mostly on top of the insulation. Could this have been caused by bats? CONCLUSIONS So, I noticed that the top of the plaster where the damp patch is and where the insulation was rolled back was bone dry! And no clear evidence of roof leakage. Also, it hasn't been raining today or yesterday (bit of snow) so it seemed odd that the back wall of the spare room was really drenched. So am I right in thinking that it is condensation from drying clothes all day and there being no working heat source in that isolated room? The moisture would have migrated to that rectangle patch on the ceiling which would be especially cold (because no insulation above it) and to the back wall (and window) as there is no radiator on in there. CORRECT? So I don't think there is necessarily a roof or pointing problem causing damp patches in spare room. Also.... Why has all the mortar stuff fallen off (seemingly in recent times in roof that is over 100 years old) - is it because of bat activity. And should I be worried about this? It seems to in most of the attic. THANKS IN ADVANCE!

Verne, Thanks very much for that. All sounds sensible and I am not having second thoughts about Roofbond. However, things have moved on. Been in attic and took a load of photos. I've posted a new thread - would be grateful for your views... http://www.thediyforum.co.uk/diyforum/roofing/199-roof-problem-damp-bats-broken-mortar-see-photos.html#post503