Should you insulate a chimney liner?

zippyj

We're having our log burner installed by a HETAS engineer in a few weeks.

The people that owned the house before us installed the stove but not to building regs, and there is no liner. It's a 1930 chimney so would really benefit from a liner.

However, the HETAS engineer who is reinstalling it for us, along with a new liner, has told us that his quote does not include insulating the liner with vermiculite, as it isn't necessary under building regulations and that stove manufacturers do not recommend it.

Instead he will insulate the chimney cavity from the room (I'm not sure what this means actually).

The two other installers had included vermiculite insulation in their quote (and were cheaper, slightly) and had intimitated that it was important to have due to reducing condensation and risk of fire in flue. So I'm now confused having had two different pieces of advice from HETAS registered installers.

Opinions very much appreciated, especially from anybody in the trade. Not sure whether to push for insulation or not, if it truly isn't needed (and insulating the cavity from the room is enough).

muckybutt

Some say insulate some dont, I sweep many many liners and very few of them are insulated to be honest.

There was a murmour I heard a while back that fitters were going off insulating due to the fact it was actually helping to reduce the life span of the liner. I have a liner that was fitted by a hetas fitter and have not had it insulated, the cavity insulation your fitter referrs to i'm presuming he's insulating the register plate above the stove to stop heat wastage there.

zippyj

Thanks for that.

It's hard to know who to trust when you've had two differing opinions from HETAS installers, so it's handy to have a second (or rather third) opinion.

alyssab45

DIY!!!!! I did and it works out much cheaper. I bought mine at Shop Chimney- an online company. They will help you figure out what you need

A._Badger

My sweep isn't keen, so I haven't had mine lined. He muttered about 'problems with damp' but I didn't want to press him on the subject as we were both on a hurry that day. As I trust his workmanship, I took his opinion at face value.

John_the_Boy

Same with my HETAS engineer, his view was that insulation wasn't required unless you have a very large chimney diameter and a lot of gap between the chimney clay liner and the flexible liner.

boyse7en

insulated my liner with a glass fibre "wrap" (looks like loft insulation/Rockwool with a chicken wire backing). I understood it was required to make the chimney draw properly. But basically the chimney firm I bought the flue from said it should be insulated so I did.

PaulF81

ours was uber tight against the flue wall so didnt bother. didnt like the idea of a load of damp vermiculite on top of the register plate to go mouldy either!

zippyj

Ours doesn't have a clay liner - it's just brick. So we don't have anything at the moment. I wonder if that will make the flexible liner a bit too loose in their. No idea how big the actual chimney passage is.

PaulF81

ours is brick too. should be fine.