Insulation around a fire place.

[Snoopy]

We have just reinstalled the slow combustion fire place in our house after re doing the floor. I have noticed that the gyprock wall around the fire, which sits in a corner, gets very hot - in fact too hot to hold your hand on for more than a second or so (it's about 6 inches or so from the back corner of the fire box to the wall at the closest point). To help reflect the heat back into the room I would like to install zincalume miniorb sheeting in this corner, but what should I do to insulate the wall material from the heat? I figure I would have to remove the gyprock and replace it with a fibre sheeting first.

Can anyone suggest what I should do? The miniorb idea is very popular with the other half. Do I need to use special fasteners to insulate the wall/studs from the heat, as I would have thought that in the most extreme cases a nail would just conduct the heat into whatever it was driven into.

[jackiew]

was looking at the latest "the family home handyman" in the newsagents and they have a feature on installing a fireplace where their hasn't been one before. They didn't seem to do anything special to the walls but for the floor they had 2 sheets of cement sheet with a steel sheet sandwiched between them with a whole load of hollow steel tubes between the sheets and the wooden floor. I was interested in reading it because as, mentioned in anothr thread my house is a bit lacking in heating.

the back of their firebox in thearticle seemed to be quite close to the wall ...

AS 1218 Installation is the standard for installation of slow combustion fires.

A quick poke on the internet gave the acceptable distance to nearest flamable materials if the fire is not in a corner is 150-225mm but if the fire is in a corner then the distance to the nearest wall is given as 650mm

In the uk you can buy rolls of reflective foil to fit to the wall behind hydronic radiators .... these are usually pretty close to the wall and can get too hot for you to want to keep your hand on ... the foil is supposed to reflect heat back into the room.

[ozwinner]

Hi
I am sure that if you leave an air gap between the tin and the wall you shouldnt have any problems, but I would just try a dry run first, just to make sure.
You could also make a double skin of tin, with the back skin full height, and the front skin cut on a wavey curve, that would also add some feature to the tin.

Al

[Barry_White]

As Ozwinner says if you provide an air gap behind your mini orb it should be ok. wants to be at least 15 to 20mm and leave a gap at the bottom to allow ait to come in at the bottom and you will get a natural cooling effect with the warm air at the back of the mini-orb tending to rise pulling cool air in from the bottom you could set it out from the wall by putting some screws into the wall studs with some aluminium tubing on the screws to space the mini-orb out from the wall.

This was how I used to protect timbers in the roof when I had oil heater flues passing to close.

[soundman]

Be verry carefull about such matters.
From the reasearch I did when I installed our wood heater the metal option is NOT acceptable at all & provides NO significant protection.

Firstly is it a proper slow combustion or a pot belly stove.

If it is a pot belly it shoul be something like 900 to 1200 from any flamable surface (not a well known fact) with a similarly large hearth.

If its a jacketed unit it may go as close as 50 to 100mm to a surface depending on manufacturer.

When you buy a new wood heater the clearances and hearth size will be clearly stated.

Your hearth and any heat guarding on the adjacent walls must be highly heat resistant.
NO METAL is considered appropriate on its own nor are tiles.
Brick work or concrete are (usualy) considered ok.
Compressed flat sheet ( heavy fibro like stuff ) of at least 10mm is the prefred material and is used as the basis of the heatprofing, tiles or whatever are then laid over the top.

Don't muck arround with this do it right or you may burn.

Check the specifications from the heater manufacturer and the australian standards. Both will be very specific on what is required.

There are heaps of horror stories about badly installed wood heaters.

If its not right & wont easily come up to spec' do not hesitate to start again.

[ozwinner]

[QUOTE=soundman]
If it is a pot belly it shoul be something like 900 to 12000 from any flamable surface

QUOTE]


Must be a big room 12M.

[RETIRED]

I thought so too, so I fixed 'cause I can

[soundman]

I meant 1.2 metres. Though If you have seen a pot belly fully stoked in a dark room (red glow comming out of every joint) 12 metres may seem more reasonable.

Pot bellys were originaly designed to stand in the middle of a room on a large hearth.

[Snoopy]

Thanks for all the advice guys. I know this is something you have to get right, that's why I asked. The fire is a fully enclosed, double skin slow combustion type.

Reckon if I combine both Barrys and Soundmans ideas I should end up with what I would term an acceptable level of overkill (what I lack in skill, I make up for with over-engineering!). I will remove the gyprock wall sheet to about 1200mm and replace with 8 or 10mm cement sheeting, then leave an air gap of 15mm with miniorb over. I will not install any kind of skirting (as the miniorb will cover the rough edge on the tiling) and will finish the top edge with an overlapping timber piece that will disguise the ventilation gap at the top. Sound OK to everyone? Thanks again.

[soundman]

remember its the compressed sheet thats doing the work the mini orb is purely astetic.

Don't use any timber inbetween.

[IanA]

There is some very sound advice here.

Be very careful to comply with either the manufacturers recommendations or the Australian Standard. Most manufacturers have their heaters tested at an independant laboratory, and the clearances to heat sensitive surfaces and appropriate shielding are covered in the compliance certificates.

If you don't correctly install the heater, and you have a fire, your insurance company may just dump you. Not good economics!!!