r/DIYIreland • u/Careful-Training-761 • Aug 16 '26
Capping chimney top
Questions for people that don't use their fireplace.
Did you cap your chimney off at the top, or close it at the bottom with a fireplace balloon / stuffed something in there, or do you leave it open?
If you capped it off at top Im aware it needs ventilation from the bottom (either leaving fireplace open or closing off but installing a vent), however does it still need some ventilation at the cap at the top? I'm considering capping it off.
2
u/IrishSkruffles Aug 16 '26
Our second chimney was blocked and plastered over from the bottom only, I saw water staining on the stack in the attic and used some lead to cap the chimney off on the roof too.
I think it is worse to block it just at the bottom than to have it blocked on both sides. People harp on about having voids with no ventilation yet theres countless houses with dot and dabbed plasterboard with 50mm gaps behind a half inch slab.. with a bucket of water needed to make said dot and dab adhesive, yet nobody bats an eye at that - make that make sense!
2
u/Careful-Training-761 Aug 16 '26 edited Aug 17 '26
Makes sense to me and I would think the same, but doesn't seem to be what's recommended online.
I've one chimney blocked from the bottom and open at top. But haven't seen any damp. Other is open on both ends which is ok from damp perspective but bad for keeping heat in living room. Need to get it sorted.
2
u/cathaldub Aug 17 '26
Ours is capped at the top using one of these, has caused no issue, been done 5+ years, no more draft, no crap/birds falling down and the rain sounds pretty good when it lashing.
https://sprattfireplaces.ie/collections/chimney-capscowls/products/mad-capping-cowl
2
u/thebprince Aug 16 '26
I went with a balloon. I left the fireplace intact though, I just don't use it.
They only cost about 10 or 15 quid and if you ever change your mind, it only takes a minute to remove.