Wood burning stove

[keatsie]

Hi to everyone.

I am after advice once again, we are putting a couple of wood burning stoves into existing fireplaces and a couple of questions keeping coming up.

Do we need to get permission from the conservation officer and do we need a flue lining. The later our chimneys are extremely large with a fantastic drawn especially due to the size, the inside of the stacks look really quite good, so is a flue liner really needed?

Cheers

 

[88v8]

Permission?
AFAIK not unless you're altering or removing anything.

If you're thatched then a liner is essential.

Otherwise, I was starting to say that I would be inclined to put one in anyway. but then, what's stop you just poking a couple of feet of stove pipe up the chimney, after all it's only a fire in a box, why would it not work.... errmmm.....

- if you don't close the top of the stack then rain will come in and fall on the stove
- your insurers might get agitated
- Building regs require a liner and no HETAS installer will fit a stove without.
- if you get downdraft in one stack you will get fumes coming back into the house, which could kill you, somewhat inconvenient. Otoh if you've lived in the house long enough to know that that never ever happens, it's not an issue.
- the exhaust gases from a woodburner are a lot hotter than an open fire and may damage the parging.

I think... if you have a good draft, I might be tempted to try it. But and it's a big but, I would not put in a register plate. That will keep the chimney temperature down and ensure that the stack is well ventilated so it doesn't get damp from the rain coming in.
However, in that case you still have all your expensive hot air rushing up the chimney, which undermines the merit of the woodburner. And of course it's a lot more difficult to sweep the stack than it is to sweep a liner.

So I think on balance I would have it lined. Which leads to the matter of chimneypots and stacks and what might need to be done to avoid uglification up top. Some sort of terminal is needed to keep the rain out, but any existing historic pot should remain.

What age is your house? Do you have pots, or is it an open stack?

Ivor

 

[a twig]

Liner all the way, makes sweeping a lot easier as well in my experience

 

[noj]

Found this thanks to Mr Google - makes a pretty good argument for a liner

Most chimneys, certainly in older properties, were designed for open fires where you are losing 80% of the heat up the chimney and only getting 20% into the room – as well as having a wicked draught around your ankles. Open fires are what wing backed chairs were designed for! All of this heat takes up a fair amount of room and is travelling upwards quickly. It is travelling so fast that it doesn’t cool and condense until it reaches the top. This is how an open fire and chimney should work.

When you put a stove or woodburner at the bottom of your chamber, you instantly reverse the ratio. 80% of the heat comes into the room and only 20% is lost up the chimney. This vastly smaller amount of hot air is therefore swirling around a large chamber, it is moving upwards much slower and leaves behind all sorts of sooty deposits which form as creosote, on it’s much slower journey, providing much more scope for a chimney fire. It is inevitably going to cool and condense before it reaches the top and the condensation, when mixed with sooty deposits, produces sulphuric acid which eats into the mortar and brickwork of your chamber. Over time this can affect the structural integrity of your chimney or cause minuscule cracks through which fatal carbon monoxide can leak.

By lining your chimney your chamber becomes a smaller and constant size all the way up enabling the smaller amount of heat to rise faster and not condense before it reaches the top. You have recreated your open fire chamber in a smaller version to accommodate the smaller amount of gases! By having a smaller and constantly sized flue, you have also made it much easier to sweep and there is no scope for flammable creosote to collect in any nooks and crannies!

If this isn’t enough of an incentive, an open fire draws ferociously (hence the draught and the need for your wing backed chair) as it has to feed the big chamber. A woodburner or stove cuts off this massive updraught as you are controlling the air intake so you need to reduce the size of your chamber to maintain the status quo of the draw. Imagine drinking a drink through a fat straw and a thin straw…. the thin straw is much faster.

Building regs don’t state that you have to line your flue when fitting a woodburner or stove, however they do state that you must be sure that the chimney is in good working order and has been sufficiently maintained. In our view this is a very difficult thing to have long standing peace of mind over! For all the good reasons stated, most, and certainly the conscientious installers will strongly recommend fitting a liner, and may even refuse to install your stove without fitting one.

If you are still in doubt as to the need, give your local fire brigade a call – get their view on installing a stove or woodburner without lining the chimney!

 

[keatsie]

As always, many thanks for the responses.

We are opting for a flue liner for all the reasons stated, we will finish the top in a clay period looking pot in keeping with the house, which was built 1580 ish.

 

[GPHouse]

Just been through this process myself.

If you're putting a fire in you should be getting it installed by a Hetas registered installer... if not you're meant to get building regs people in to sign the installation off, which in N somerset is about £150. there are a load of regs - summary in the diagram attached of spacing to assist - it's where most people aparently fall down!?

We looked at this too and opted for the flue - it massively reduces the risk of fire, makes cleaning easier and with some of the new fires maintains and regulates eficiency (heat and airflow) which is really important.

We have one room with a burner at either end so draw and drawback were especially important - we have a Morso 4 and a Burley Holwell (really really good after the first 4 or 5 burns).



G

 

[d49xc]

Permission?
- if you don't close the top of the stack then rain will come in and fall on the stove

Not in my house.
All the brick flues have kinks in them.
The ground floor flues have a kink as they pass though the first floor joist level and then again another kink along with the upper storey flues in the loft space a foot or so above the loft floor.
Careful measurement shows that the stacks emerges in the upper story rooms slightly offset from their positions downstairs due to the kink being located at this level.
This means any rain falling directly into the chimney never gets down to the fire below as it is absorbed into the brickwork.
It also means that for the unused flues the bottom can be (and are) totally and completely sealed off and plastered and wallpapered over with no ventilation access at all without any problem of damp occurring at the base.
The upper kinks also serve tiresomely as a ready made bird nesting ledge - hence the strong wire netting over the tops of the pots.

 

[kreyszig]

It also means that for the unused flues the bottom can be (and are) totally and completely sealed off and plastered and wallpapered over with no ventilation access at all without any problem of damp occurring at the base.

open at the top, closed at the bottom, no ventilation. sounds like a recipe for damp to me!

 

[88v8]

Kinkiness is a relatively modern attribute.
In the OP's house of 1580, I dare say he could and regularly does lie in the hearth and look up at the sky, as could we in our inglenook until we had the stove put in.

Ivor