On 05/11/2014 16:26, David wrote:
On Wed, 05 Nov 2014 15:54:54 +0000, Andrew Gabriel wrote:

In article ,
David writes:
Need a couple of unused chimneys capping.

First quote:

scaffolding £600 parts and labour £250

Looks like they may not want the job.

IIRC, I paid £450 for the scaffolding, and I did the work myself, but
that also included repointing the chimney and redoing the flaunching. I
got a lead guy aroumd to redo the leadwork.
Also aligned the TV aerial whilst up there. (I worked out the angle from
google maps, and used the car satnav to get north,
and then set the aerial. Then I discovered that if I looked very
carefully at the horizon along the line of the aerial from the top of
the chimney, I could just about see the transmitter 25 miles away.)

Gotchas about capping chimneys?

Most of the chimneys round here just have a half round tile over the
top. Is this enough to keep out the rain, and allow some ventilation?
I know that rain is coming down the chimney because the hearth is open
and soot is coming down despite having swept the chimney.

Ventilating is very important or the chimney fills with condensation and
wrecks the internal decorations and plasterwork about 5-10 years later.
Must be vented at top and bottom.

You can get vented caps which sit on the pots - earthenware with a ring
of vent holes around (which are mortared on to the pots), or metal
(Brewer's) caps (which have a strap around the pot which I didn't like
so I fitted them a different way).
Another option is to remove the pot and seal the top with a paving slab,
and put a vented brick in the side of the chimney near the top.

These all have quite different appearance, which may be important if you
don't want to change your chimney's so they don't match everyone else's
anymore. The Brewer's cap is the least visible from the ground. (There
are also Brewer's caps which leave the chimney sufficiently open to
still use it, but I'm not referring to those.)

Ventilation is more important than stopping water getting in, i.e it's
better not to cap it at all than to seal it in a way which kills the
ventilation.

Capping a chimney doesn't stop debris coming detached from the inside
and falling down.

I think I favour the earthenware vented caps - drop into a bed of mortar
sounds good, and they also look attractive.

Stage two of the plan is to block the chimney near the bottom and put a
flue door in the outside above the blockage for maintenance access.

That way I can seal the barrier from above and also get at it to check and
clear out any debris at a later date.


Makes me wonder about sealed fire places with just a ventilation brick -
presumably they are at risk of slowly accumulating debris. Fortunately we
only have one remaining chimney which serves the lounge and one bedroom.
Must make a note to check out the bedroom (lack of) fireplace.


Cheers


Dave R



A chimney sweep will advise and fit. It's part of what they do.