We are considering having a wood burner installed as a secondary heat
source in our front room, we live in a rural area, have access to
plenty of fuel and no storage problems. Not using it to heat water.
However we do have one minor problem.... we have no chimney stack!
Previous owners have had it removed down to just above bedroom
ceiling. Having it rebuilt will not be a problem, but the question I
have is, do we need it lining?
There are four fireplaces in the house, two up and two down. We have
no intention of ever having fires upstairs and unlikely to have one in
the other downstairs room. I welcome the opinions/thoughts/suggestions
(polite ones please) of the 'team' .
If it has any bearing on the issue the fire would likely only be lit
during winter and then only three or four times a week of an evening,
in other words, light use.
House is a late Victorian terrace with a hideous gas fire in the
fireplace, was swept very recently; before gas fire fitted (by
If you're having the job done of reconstructing the stack through the
loft and the roof then it's absolutely worth having the chimney lined at
the same time.
Chimneys have a tendency to crack over time which means smoke and tar
deposit leak into the rooms, causing a smell and making stains behind
The other advantages are that it'll probably draw better and it'll stay
clean longer and be easier to sweep.
Two downsides I can see, would look odd on a Victorian house, and
would require some rather good lead flashing to make a good seal
around a non-standard roof penetration (i.e. you can't use a standard
lead slate, nor can you cut and tuck lead sheeting into the
OTOH it must be done routinely where these pass through roofs (rather
than through walls) where there is no chimney to use at all. I haven't
seen the detail of how that is usually done though.
For that matter, if the stack has been taken below slate/tile level -
it will still require someone with the art of leadwork to make good
around a brick chimney.
From a building regulations point of view, it *may* not be required to
line the chimney - if putting it back into use is considered a
If OTOH it's regarded as disused, building regs would I think apply.
However there's several reasons why it's a good idea to line
Stainless steel liners for solid fuel are far from cheap - think about
costs being similar to a good quality stove (also don't be misled by
the price for linings for gas boilers - they're much cheaper but
unsuitable for solid fuel).
However if you're having the chimney stack rebuilt, that's the ideal
time to have a liner put in. It isn't unusual to have to at least have
to take the pot off anyway, and often the flaunching requires repair.
Other important stuff is the chimney is well designed to draw well and
avoid downdraughts - which depends on a myriad of things, surrounding
terrain/buildings/trees, shape of your roof, height of chimney above
roof - some of which may have changed since the original build.
A liner helps the stove to draw well, which reduces sooting and
improves rapid heat-up (reducing the chances and consequences of a
chimney fire - which can be bloody scary) - and in some cases may be
important for safety.
Ideally you want to get a look at the state of the masonry inside the
chimney. The combination of many years of usage/sooting along with
rainwater can lead to considerable mortar erosion - in which case
definitely don't skip the liner.
If the chimney is significantly larger than the liner, filling the
space between with vermiculite is common practice.
Take Christmas as an opportunity to stuff smaller relatives up the
chimney for closer inspection.
Much good advice in Part J of the building regs:
If you have a woodburning stove then need to have a stainless steel
flexible flue flue of the correct diameter to go with it (I guess this
is what you mean by lining) otherwise it will not draw properly. I
think the question should be: do you need to re-build the stack or is
there a cheaper way of venting the fumes?
Only premissible if te existing flue is sound.
And generally a Bad Idea for a wood stove. Use solid insulated double
walled STAINLESS STEEL. Aluminium corrugated will not survive a chimney
fire, or even a good roaring fire.
It is permissible to take a stainless steel flue straight through a
timber framed roof with no stack whatsoever. Just a pipe sticking up,
I've been following this thread with interest,
as I am thinking of installing a wood stove in a Victorian cottage,
which surprisingly has a chimney stack in the middle of the main room.
(The cottage was originally the wash-house for a neighbouring orphanage.)
Would I have to line the existing chimney up to the roof?
Surely it should not get very hot except close to the stove,
or the heat-loss would be very large?
Doesn't the requirement of a flue line have something to do with ensuring
sufficient draw on the fire? Here's what my instructions say for a 4.5kW ish
"If connecting to an existing chimney with a flue diameter of more
than 150mm it is necessary to line the flue using a
suitable stainless steel flue liner."
My recent experience of all this suggests you might just as well go down
the local fireplace shop and pay a silly price for the whole
installation. HETAS registered engineers are the only people allowed to
install flues, and they all seem to be owners of fireplace shops.
No, they are not. Anyone can install one BUT they need to raise a
building notice and get it signed off.
HETAS people are the only ones allowed to SELF CERTIFY their own work..
I in fact installed my own.
Its up to you whether the cost of the building notice exceeds the extra
cost of a HETAS installer.
Our Hetas bloke wasn't. The local fireplace shop does have an association
with someone else, but he never called back, so I picked a couple of local
chaps off the Hetas site and gave the job to the one I liked.
200 quid labour, (including sticking a couple of vent caps on the open pots
on the other disused stack which for me is a bastard to get at) which I
didn't think was too bad and paled into insignificance compared to the cost
of the liner (which I checked and could have got no cheaper myself and came
in at 500 quid). He cleared up nicely and took the old gas liner away.
It's worth noting, that of course you can do the job yourself under a
Building Notice - but for a professional, they should be Hetas.
there;s loads on here from a while back about this perennial favourite
- including some by me.
In essence you will be loads better off lining the lot - easier to do
and sweep properly, better draw, you do not want to risk your crumbly
old masonry leaking flue gases... or being attacked by combustion
products (esp from stoves) and becoming leaky (gases or rain)....
in any case how would you sweep a partially lined flue??
it's not just about heat tho is it?
your stove should be regulating the amount of air entering it and thus
the amount of hot gases going up the flue
As for the OP "modern" flue pipes can look OK. could you send it out
the wall at ceiling height then work it up outside - even easier
cleaning but not if you're in a terrace.....
Oh, it is. About 70% of the heat gets wasted..
But regulations are regulations, and there are reasons.
The most pressing being that wood burners get very hot, and also that
they can and do produce tarry deposits which make a chimney fire very
likely at some point.
That's when the WHOLE flue gets red hot. And tats why the modern
regulations for a new installation insist on double skinned insulated
Round here, teh classic chimney fire that burns a house down happens
- internal pointing fails, and red hot gases leak into the roof space
- thatched rooves get set alight by settling red hot ash particles
- the flue itself simply gets red hot and ignites any timber attached to it.
I had a rather special interest in this, having watched my wife's
sister's house burn down and being about to build a thatched house, and
having the local volunteer fireman as a casual friend.
Oil and gas are less a problem: they dont have such a wide variation of
flue temperatures, and the fuel is clean enough to not leave tars.
On my open fires, I had to provide outer brick and line that with
ceramic flue liners. And build the stacks up WAY above the thatch, and
decouple any wood work from the flue structure with fireporoof board.
On the other double stack, which has an Aga and a wood burning stove, I
had been told, erroneously, that only flexible lining was needed inside
a blockwork stack. This proved to be wrong: New builds must have either
ceramic block lined flues, which I THINK is permissible for a wood
stove, or better, double steel insulated flues. In which case the
blockwork stack itself was totally redundant and mere 'decoration'
I do know the aga flue is much less expensive and to much lower spec.
Its the wood and coal that need the really heavy duty fire proofing.
Oh, and I have set chimneys alight on 5 occasions now..not here, yet,
but elsewhere. I can assure you that the temperature and rate of
combustion are frighteningly high.
Its a lot easier to do than you think.
So, that's my assesment of the risks, and the reasons for the regulations.
I would say that unless ou have a flue in good condition all the way up,
and pre 1967, don't mess with a flexible liner. If part of the flue has
been removed, or the build is newer, you will almost certainly be
required to fit a double skinned insulated flue anyway, and you might as
well take it all the way up and simply leave whatever stacks you have as
And not get hit by the insurance company if the place catches fire. They
tend not to pay up on properties that don't comply with regulations.
I will add:
I've just had my stove connected and the chimney lined by a Hetas registered
chap, complete with paperwork.
He recommended a high quality single skin SS liner which is what he
installed. This was to an existing stack in good external condition (though
there is some loose internal rendering as evidenced by the small pile of
dust and lumps that fell out whilst he was dropping it down.
I'm bedding the fire in so it hasn't run at full blast yet, but exposed bit
of the flue from the top of the stove isn't running as hot as I would have
imagined. Hot but not skin-rippingly so. What's coming out the top doesn't
seem that hot - well, not enough to upset the TV aerial 12" away.
 I had it in mind to do this myself, but I'm glad I didn't. Access is
excellent - one can stand on the dormer flat roof and work on the stack at
chest height. But watching him assemble a random bundle of parts down the
bottom to couple the liner to the stove, I fear I simply wouldn't have had a
clue what parts to buy or exactly how to put them together correctly. I did
make sure that I was appraised of the final connection and sealant used,
just in case I need to remove and refit the stove in the future.
 The aerial's not great so I'm not bothered if it dies - it's on my list
of 'tuits. I just asked it be left alone if he felt happy doing so.
It will be a simple matter to refit a longer cranked mast to get the main
aerial and plasticky bits a good 3 foot away, and mount it round the round
the other side to boot.
Abstract thought - do you need the whole stack or can you do something with
a twin walled flue, and maybe some fireproofed boxing in?
I don't actually know, but I'm thinking of all those log cabins (some 2
storey) with iron stoves...
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