I have recently moved into a 100yo house. The felted slate tile roof seems in very good nick and the survey at time of purchase found no problems. Recently we developed dampness in a bathroom and a roofer had a look and did some repairs to pointing around a chimney at a corner of the house and adjusted the lead in some way. There was exceptionally heavy rain for days before the damp appeared in the bathroom and he said he thought rain was getting in under the tiles at the edges when it was very windy. He said he was 95% sure this would solve the problem which was obviously chronic as there was some damage (rot) to some of the wooden beams in the roofspace, just at the corner of the house, but 'nothing serious'. The latter has alarmed me somewhat and I went up to roofspace for a closer look. The main beams seem fine and are obviously treated, but there is some rotten wood right at the corner, underneath where bricks from an unused chimney begin and also behind an adjacent gutter. I suspect the fascia board is rotten and can see the white gutter through a small hole in it, again confined to this corner of the roof. One foot away from this area, the wood seems sound. Apologies firstly for my somehwat vague and ill-informed description of the problem. I have no expertise or experience in this field (or diy in general!) and hence am looking for some advice and hopefully reassurance. Does this sound like a major problem which I need someone else to look at for a second opinion, or does a little rotten wood under an otherwise very stable-seeming chimney require no intervention at this stage other than to fix the leaking roof causing it? I am awaiting rain to see if the latter has been successful but regardless have concerns about the wood damage. Roofer seemed knowledgeable and trustworthy but I have no idea about these things.
I don’t think there are too many roofing specialist on the forum however first thing (as you have) is to address any water ingress. Then assess. Any rot will only get worst but at what rate depends on many things. If the fascia is holed from rot then it needs replacement to keep water and vermin out. I had this in one of my places and addressing the water ingress (rotted gutter overflowing at the back) and replacing the facia had dealt with it about 90%. May need some work on the truss ends down the road but if is not a risk. Honestly without seeing it in person I don’t think anyone can properly answer for you.
I would have to see the rot and poke around a bit to know for sure to know if it needed replaced, there are some liquid stabilizing products that can help with the not so deep rot. To repair or not also depends greatly on what the rotten wood is doing, if it is load bearing your standard for replacement would be much stricter. Pinpointing a leak is sometimes very difficult but that is what I would do first, don't wait for a rain, you want everything real dry, then direct water flow over a small area at a time starting from the bottom, preferably while someone in the roofspace watching.
as said above, use a garden hose to figure out where the water is getting in, fix that leak, the pull the gutter, remove the bad fascia board, do any repairs/reinforcements needed behind it, then replace it. one important thing you haven't stated is how high off the ground is this leak -- that's a big deciding factor in how much DIY I would recommend.
@ellamacrow The first thing I would focus on is stopping any additional water damage. I would add additional sealing to all areas Around your possible leak. Once you have done the additional sealing I would use the hose method and apply some serious water to the suspected leak area to simulate rain + wind. As far as wood replacement. Unless the wood/ beams are obviously structural/ load bearing I would wait until the wood is very dry to make any decisions on the extent of the damage.
Not sure your budget , but a bucket of hot thin roofing tar and a brush / might be a quick fix to buy you time. Seal around the chimney flashing, let it cure, then do it again for good measure. Might buy you a year or two
I’m going to go the opposite on this. Roof leaks on a normal asphalt roof can be very very challenging. I would search around and find someone that specializes in slate. A lot of times homeowners can do a lot more damage trying to seal something up. Do not seal around the chimney area with tar. I’d rather get a second opinion. You could take a very small problem and make it a lot worse. I am a licensed roofer and have done many. But absolutely hate doing them. They are monkey work. slate roofs are a different ballgame. He was right. Depending the weather/wind you will get water coming in. That is completely normal for that roof type and there’s nothing you can do about it. mid you only have one spot it’s coming in under normal rain conditions. Well I’d search around and get someone else up there to look at it that really likes that style roof.
