Wood burner squeeking flue when windy

John_the_Boy

rock wool is idea, it is used to insulate around inset stoves so around a flue would be fine.

nazuro4013

Thanks, I think I need to somehow maintain the airflow though and have concerns about rockwool touching the flue directly. My plan (unless someone points out this isn't a good idea) is to get some acoustic mineral wool like Rockwool RWA45, cut into strips that I can feed through my newly cut hole and affix to the plasterboard on the inside of the boxing in, ensuring a sufficient clearance of 50mm to the flue. Hopefully this will reduce the sound transfer into the bedroom. 

FreeBear

I suspect you have a double wall flue with insulation between the inner & outer skins. One of your photos in the opening pots shows a plastic "guard" up in the ceiling. If your flue was single skin, that plastic would have melted a long while ago.

The joints between each flue sections are often push fit couplings. Sometimes, a locking collar is fitted - Tightening these up (if fitted) might reduce the noise a little. Stuffing the void inside the boxing with insulation should deaden the sound a little, but don't hold your breath. Also bear in mind that you are currently getting a fair bit of heat in that bedroom from the flue (when the stove is in action). Insulating the void will reduce the amount of heat getting in to the room.

WIAWSNB

I think it's important to ID the type of flue first. Take a circumference/diameter measurement, and look for ID info on it.
Flues work best when insulated - they warm up quickly, and hence 'draw' properly.
I don't think your idea will struggle to block out the sound.
So, personally, I'd ID the flue, confirm it's twin-wall, and then get stuffing. Sounds will travel through any gap, so it needs packing in to also reduce the mouse from the room below.
This might be all you need to do to sort both issues - the squeak and the mouse travel, with no wall cutting. Got to be worth a go.

nazuro4013

Hi all!!

I managed to cut the plasterboard out using a multitool  . The source of the squeek I think its the bracket pictured. Just about cut the hole high enough for me to reach it! I've ordered some "fire rope tape" which I plan to put around the flue beneath the bracket so that there's no metal-on-metal. Hopefully this is a good idea?!

I've also just ordered some 75mm RWA45 acoustic insulation which I will put against the inside of the plasterboard. This way there is still room for air to circulate.

We don't actually the log burner and don't have any plans at present due to concerns around internal (and external) air pollution. 

WIAWSNB

Ok, so ignore everything I said :-)
I suggest do not modify the flue joints in any way. You might not use that fire, but your successor might do. 

nazuro4013

Yeah I'd already cut it out before I saw your recent post. I wouldn't have been able to stuff anything up there anyway, i can barely get one hand inside from below. It's the bracket that's squeeking not the joint. I won't do anything to the joint other than tighten it if possible

WIAWSNB

You still appear to be under the impression that the actual flue needs to be ventilated. It is almost certainly already insulated, and the reasons essentially twofold; one is to prevent heat damage to the surroundings, and the other is to keep the internal flue sleeve hot so it draws properly.
Packing further suitable insulation firmly around it should not be an issue - but always confirm with the manufacturer.
You had another issue, that of sound travel from the room below. Airborne sound will pass through any tiny gap, and you trying to line the inside of that boxing will, I believe, make very little difference; you ain't going to line it all!
But, a 'plug' of tightly-packed insulation around the flue as it comes through from the ceiling below, should. You have access via this hatch - pack down around it for a good couple of feet height. 
After checking with manufacturer or HETAS installer...

nazuro4013

The log burner company I had round to quote, said "The void cannot be filled with anything, it needs to breathe through its length to stop heat buildup within the fabric of the building."

This is why I opted to use acoustic board on the inside of the plasterboard. It's not going to be perfect but better than nothing.

FreeBear

WIAWSNB said: You had another issue, that of sound travel from the room below. Airborne sound will pass through any tiny gap, and you trying to line the inside of that boxing will, I believe, make very little difference; you ain't going to line it all!
But, a 'plug' of tightly-packed insulation around the flue as it comes through from the ceiling below, should. You have access via this hatch - pack down around it for a good couple of feet height. 
After checking with manufacturer or HETAS installer...

Another issue is the cold draught coming down from the roof - That needs plugging, and tightly packed insulation will help. Rockwool is rated as non-combustible, and (in another life) I used a lot to wrap round industrial flues.