Went up to repair a rattly cowl yesterday evening (dry roof and no gale for the first time in a month) and noticed that the buff chimney pot is beginning to crumble around the rim, presumably thanks to sulphuric acid being formed from the flue gases. I'm quite surprised; we have only owned the house and been burning solid fuel for 7 years. Is there a difference in hardness and acid resistance between buff clay and red terracotta clay pots?
I also put a new layer of flaunching on the old about five years ago using a 3:1 mix and this has almost all been washed away, with a couple of "valleys" formed in it by running acidic water.
So I will renew the lot next summer. What kind of mortar should I use for the flaunching? Are all pots equal or are there some better than others?
I also put a new layer of flaunching on the old about five years ago using a 3:1 mix and this has almost all been washed away, with a couple of "valleys" formed in it by running acidic water.
So I will renew the lot next summer. What kind of mortar should I use for the flaunching? Are all pots equal or are there some better than others?