Chimney leak

I have an old house and there are a couple of issues that need to be fixed on the roof. The chimney breast has water coming down into the inside of the attic. The wall is quite damp, it is not running down the wall. I also have a couple of cracked tiles (the tiles are an old style that would need to be sourced from a salvage yard).
I also have an old cast iron attic window that needs to be replaced. I would replace this with a modern velux one.
The chimney concrete rendering has a large crack running right down it.
I have had a couple of guys come out to take a look at it. One of them knew the type of tiles and where to get them. He also said the source of the leak was the flashing around the chimney. They have not been on the roof to inspect only viewed the chimney from the attic window. The second guy thought it was probably the crack in the rendering letting the water in, he thought this would be expensive to get done and it was not something he would do himself.

  1. If the rendering needs to be redone, what should I expect to pay for this? The house is 2 storey.
  2. Can anyone recommend a roofer that would be able to do this work in the south dublin/north wicklow area.
  3. Anyone any experience with Allguard roofing?

Thanks a lot for your help, I am getting a bit stressed about this as I am getting conflicting opinions from the guys coming out to view it.

Contractors are selling you their services, Get an Engineer/Architect/Surveyor to look at it and give you independent advise. Then set out a brief of works to be done, then go shopping for builders

  1. Don’t panic!
  2. Yes, both the cracked render and the flashing could be letting water in.
  3. The expense with chimney repairs comes with scaffolding - it’ll take a couple of guys the best part of a day to erect and then again to dismantle the scaffolding; the work itself sounds small (weather dependent).

I’m not a builder, but did have to have a chimney repointed, reflashed, new pots, and some tiles fixed etc. Many years ago on a 1930s redbrick terrace in the UK, but I don’t believe the method has changed.

If there is a noticeable leak (as opposed to dampness) then the problem is a lot more likely to be the flashing against the chimney rather than a crack in the render.

The cheap option. The flashing of tiles is very straight forward to fix and could easily be done from a roof ladder. At the same time the crack in the render could be caulked to prevent any further medium term issues.

**The not so cheap option. ** You have an original roof that is getting old and it is showing it’s age. At some stage you will have to pay to do a job that will last another 60 years. This will give you the opportunity to increase the insulation, treat the timbers, new roof felt, replace the roof light, address any issues with gutters, render the chimney if necessary, do the flaunching on the chimney top (the likely cause of the crack) etc etc. It’s not that big a job because the tiles will all be reused. Material costs wouldn’t be much so it’s all just labour and scaffolding.

If I were you I’d do the cheap option now, and do the second option in the spring/summer or as soon as you can afford it.

Thanks. Any ideas on costs? I dont really want to go with an expensive option at the moment.

It really depends on the extent of the works, the size of the roof, and (most importantly) the type of roof. A terraced house would be quick and easy and might cost €4.5-5k for scaffolding, removing of tiles, treating of timbers, new felt and batons, new flashing, reuse of tiles/ridge caps, fitting of Velux, gutter and chimney repairs etc). A semi D with a hipped roof is a bit more complicated and slow and could cost €6-7k. Much of the extra cost is down to more breakages of ridge caps and tiles and the need for more scaffolding. You might get it done cheaper than that if the builder does his own scaffolding. A lot do.

With roof problems it’s worth having a bit of a contingency in case there is more extensive problems with rot or woodworm.

it is a hipped roof. What would you expect to pay for the replacement of a few tiles, new flashing and replastering of the chimney breast?

There is a far bit of work in rendering a chimney because you need good safe access. Unless the render is loose or hollow I’d leave it alone and concentrate on dealing with the likely cause of the problem, the flaunching around the chimney pot. If this was properly repaired and the crack in the render was caulked it would probably be fine for 10+ years. If the crack is large (more than 2-3mm wide) I think you’d be best to get a specialist to look at it.

If you don’t have to render the chimney then it’s one day of work for 2 people. They will want (and deserve) a good premium for their work, but assuming about €60 for lead flashing, I think it shouldn’t cost more than €500 in Dublin, maybe €450 elsewhere. Only get an experienced local builder to do this kind of work. No cowboys. They must have their own insurance.

I’ve a very similar problem. I’m assuming it’s flashing around the chimney – has been leaking since the house was built. Took several years to notice the paint peeling off the chimney breast, and at the current rate of progress will take several years more to find someone to fix it … although I think I may have just found them. Hadn’t occurred to me that the chimney breast would need replastering – I assumed it could be just dried out and repainted. Is that wrong?

By replastering I mean the concrete rendering on the outside of the chimney. The roofers use the term replastering with the outside as well.

Ahh. Gotcha.