Flue liner query

[Anonymous]

The inglenook in our dining room previously had an oil or gas-burning Rayburn installed. We are planning to install a multi-fuel stove instead, using a flexible flue liner. We took the plasterboard 'ceiling' of the inglenook down last night, and blimey, is that one big hole! My query is that the National Association of Chimney Engineers advice suggests that an insulated flue is essential with a multifuel stove in order to reduce condensation. I'm wondering whether we need therefore to insulate the whole length of the flue liner (which will be about 40'), rather than just insulating it where it passes through the thatch which was our original plan, for safety reasons.

The void is far too big to consider the backfilling with vermiculite/cement option, so we were considering the rockwool sleeve approach.

Has anyone out there attempted anything similar - any advice gratefully received.

 

[Anonymous]

I am about to do the same (although in a smaller fireplace). The liner isnt cheap but the best price I could find was at hotline chimneys.

Aiui, you have to have at least a 6" liner for woodburning. Our chimney is about 10" by 30" as far up as I can see (about 7or 8 meters at a guess) so I intend to try and push the insulation up from underneath. That gets me to within a couple of meters of the top and I'll see how that goes.

Just wish it wasnt raining - I dont fancy clambering about up top to feed the liner in while its like this and my wife is complaining like mad about the flue, liner, pipes, fittings etc occupying the hall. I say she should have warned me her parents were coming to visit for the weekend.

Mark


Hotline chimneys

 

[Anonymous]

I'm wondering myself whether it's easier to slip the insulation onto the whole length first, then pull it up the chimney using ropes rather than try and post it downwards.

Also, aiui we have to inform the council first and I'm wondering at what stage they want to inspect the works and frankly, what point there would be. If they come before we install the stove there's nothing to see and afterwards it's impossible to see what we've done! What's been your experience?

 

[Anonymous]

Ushy

Pulling up the chimney is I think more likely to damage the liner. Depends on the route of the chimney though. What sort of manouvers would it have to go through to get it out the top? I guess if your chimney pot is coming off and you have a wide chimney it could be worth a go. I'm going to try and get away with one of the hanging adapters. The liner is quite light, v.easy to carry

I rang the building regs people and tbh they weren't very interested. Kept going on about how the CORGI (Que?) installer would certify for me, thats after I told them that I wanted to diy it and that it would be wood/solid fuel. Got the impression that it wasnt considered very important. I did explain the age / size / construction of the chimney so perhaps they would be more interested if it was a new chimney or something. I got the impression that lots of the newer building regs are a pain for them - only needed when houses are sold and some solicitor wants to see all the bits of paper.

I aslso asked about solar water heating -they wanted to be sure the roof was strong enough for the weight, and windows (single vs dg, repair vs replace) and they were pretty much happy for me to do whatever I wanted. Contrast to one of the local glaziers who didnt want to supply a thin dg unit, only one at the full modern thickness (22mm?)

M

 

[Anonymous]

We did the same using a flue liner, It is very difficult to pull it up the chimney (it was in ours) so we had one of us on the chimney stack lifting it up and down the pot and another pulling on a rope from down inside the fireplace. It is very heavy work as the turning radius of the pipe is quite large and you need to have it coming straight down the chimney or it gets snagged.

We first dragged the whole liner up on to the roof and then droped the end with rope on (clove hitch) down inside. Be very careful when sitting on the top of the stack as it can be quite scary when it gets windy (Use brother who is a fully trained alpine guide!!!) It cane be a very messy job as well with all the old "£$% falling back down (put on goggles as I found out quickly). You can then trim the liner using tin snips (not as easy as it sounds) to the correct length and fit a cowl-hanger to stop it falling down.

I did not call the building control and it works a treat with a good draw.

 

[Anonymous]

I am pretty sceptical about the need to insulate flu liners.

The stated aim is to prevent potentially corrosive and flamable tars from condensing onto the liner by keeping it warm.

However my feeling is that a stainless steel liner open to the elements at one end is ALWAYS going to be colder than the smoke until it warms up anyway. The insulation would only be useful for the period of time when the fire is still cold enough to be giving poor combustion but the liner has not yet warmed up. During this time the insulation will speed up the warming process but it seems a lot of money for a marginal benefit.

If you have a large flu then you could probably use bog standard rockwool insulation rather than the fancy slim profile sleeves?

 

[Anonymous]

George I'd agree with those comments.
I read on suppliers website that they would only recommend insulating a liner if it was to be installed within an external stack. By this I presume this would mean a stack built onto the outside of a building because they could be much colder.

I've recently installed one and didn't insulate it the chimney is in the external wall but part of it because the walls are very thick. Also i considered that if I had insulated the liner most of the warmth that builds up in the stonework during the day would have been lost out of the chimney. Surely this would make a stove more efficient?

Alan

 

[Anonymous]

The flue in question is in the party wall, so this could be a consideration. We're mainly concerned with making sure the flue is lined where it passes through the thatch - our local news said there had been 26 fires in thatched properties in the last 6 weeks rather than about 50 in a whole year in previous years, and attributed this to the use of woodburning stoves in the very cold weather, so we want to be careful.

What we need to work out is how to hold the insulation in place if we just part-line the flue.

 

[Anonymous]

If it's a party wall then I think there is probably even less need to insulate (apart from through the thatch)

You could probably hold the insulation on with hose clamps. They make reet big ones...

G.