# Forum Home Renovation Heating & Cooling  Base for wood heater

## brettsyoung

Hi all 
I'm looking to install a wood heater in our living area and am not sure what I should sit the heater on. We have cypress pine floorboards. I have a solid compressed cement plate (about 10mm thick) which came with the heater but I'm wondering what needs to go under that. Can I just use any pavers to sit the heater on? Do I need to attach them to the floor, and if so how? 
Many thanks in advance. 
cheers
Brett

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## SilentButDeadly

Nothing need go under the compressed cement sheet.  Just screw it down to the floor. You can tile the cement sheet with whatever your preferred tiles (using typical tiling techniques) before placing the heater on top.  The heater itself is unlikely to require affixing to the tiled cement sheet.

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## Andy T

You also need to be aware that the sheet will need to extend beyond the extent of the heater and allow for a hearth. There will be regs for this. You may want to tile over the sheet where the hearth will be (maybe better to tile the whole lot) for appearances sake. Generally the bottom of the heaters don't get all that hot but coals, sparks, falling logs that may come out the door when open can be the issue.

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## Smurf

Based on my own experience, I'd strongly recommend that you do not use slate tiles.  
Mine has a slate hearth - presently held together with a large (1.2m length) clamp and concrete. Over time, it buckled toward the front, to the point of one of the tiles turning to rubble and chunks coming off the others, whilst the back developed an approx. 15mm wide split right behind the heater. The clamp is holding the back part together, whilst the concrete has filled in the hole left by the tile that turned to rubble. It looks shocking but at least it's safe in terms of not being a fire hazard etc. 
There are plenty of pre-made hearths available. Just steer clear of slate in my opinion. 
As for why it cracked, I really have no idea on that one. Maybe it was supposed to be installed differently? It was there when I bought the house and already cracking so really not sure on that one. It seems to be just sitting on the floor. Actual construction is a cement sheet base with the slate tiles on top. House was built in 1995 so presumably the hearth is the same age. 
As for securing the heater itself, they're pretty heavy so shouldn't be a problem. Mine has no obvious points intended for securing it. A look at a new one in the shop reveals that it weighs 180kg so it's not likely to move by itself.  :Smilie:

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## Andy T

Smurf - you certainly have had some issues with slate. I have a slate hearth (over a slab) with a 25YO Kent tile fire on top of this. I also cut the slate and used this for the tile bits on the side of the heater. I coated the slate with 3 coats of tile finish. The hearth is as good as the day it was installed. Even the tiles on the side of the heater are OK although I recall after installing them there were some alarming popping sounds for a few months. I guess it depends on the substructure they are laid upon.

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## Moondog55

Andy I think it must depend on the slate, my dad installed the Coonara in our house and the slate hearth he laid on top of the bricks ( Inbuilt Coonara ) only lasted about 12 years before they turned to powder. 
Dark Welsh slate is probably OK but I do not really Know

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## GraemeCook

You need to check your own council regulations on this one.   Some do not allow DIY installs. 
When I installed a Lopi wood heater back in 1983, the rules (for Hobart) were :Redface:  
*  hearth had to be masonry, brick or concrete, at least 100mm thick.
*  hearth had to extend at least 300mm from all parts of the stove.
*  nothing combustible was allowed within 300mm of stove in strait line.
*  there were also rules for the flue, which I cannot remember in detail. 
As I intended putting concrete hearth over wooden floor, and concrete is hydroscopic, a council engineer advised me to put thick plastic down before I laid the hearth.  Good advice. 
I put slate over the hearth - greenish multi-coloured stuff - and 27 years later it is still fine.  Sounds like Smurf got a crook batch? 
Cheers 
Graeme

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## brettsyoung

Hi all.  Just revisted this old post to get the job done (the cold snap shook me into it).  What I did based on advice I got here and elsewhere was lay a 1m sq x 19mm slab of compressed cement sheet, tile over the top and surround with dress timber.  Placed my smaller cement sheet and heater on top of that.  No worries.  
Thanks again to all for the advice. 
cheers
Brett

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## sooty

while on the subject of hearths. 
is there any preferred product for the base material. ply then tile underlay then tiles, compressed sheet & tiles???

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## Moondog55

Quickest and easiest is compressed cement sheet, 19mm or thicker, treat cosmetically as needed. if you have one of those wood heaters that get really hot underneath and you have timber floors then perhaps a second layer of cement sheet with an air gap created by some 25mm SHS; don't use anything combustible as a base. 
Galvanised steel sheet in two layers with aforesaid air gap would be quick and easy too.
; then underlay and tiles could work too.
A lot depends on how pretty it needs to look when finished

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## soundman

When I installed our wood heater quite a few years ago, I purcahed the australian standards. 
One important concept is that of fire resistance. 
The tiles them sleves are not considered fire resistant, neither are quite a few other things many people would consider fire resistant..... including  corogated iron, brick and fibrecement sheet in some situations 
The safe option is to base what every you do on 10 mm or greater compressed flat sheet. 
The whole concept it to provide a fire resistant barrier to protect whatever the floor or wall is made of.
The thinking is proterction from continuous heat. 
don't forget the wall clearance specifications too. 
If you dont have the wall clearance  required in the specifications for the particular heater, you then have to treat the walls. 
these days all wood heaters should come with a wall clearance and heath specification, although some local authorities may require more. 
cheers

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## Moondog55

True but wall treatment can use materials that would not be used on floors, one of the simplest wall treatments is corrugated steel sheets, just use a good airgap; it is all about reading the standard and applying it it intelligently. somethings would comply but have not been tested, and tiling can be used but not if it uses anything but a cement based mortar.
The easy way i look at things is this, "Would I trust my life and that of my family to what I have just built??"

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## brettsyoung

just about there ...

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## elvolvorules

Hi Soundman 
You mentioned that you bought a copy of the Australian standards. 
May I ask, do you still have them, and if you are finished with them are you willing to sell them? 
Cheer 
Alan   

> When I installed our wood heater quite a few years ago, I purcahed the australian standards. 
> One important concept is that of fire resistance. 
> The tiles them sleves are not considered fire resistant, neither are quite a few other things many people would consider fire resistant..... including  corogated iron, brick and fibrecement sheet in some situations 
> The safe option is to base what every you do on 10 mm or greater compressed flat sheet. 
> The whole concept it to provide a fire resistant barrier to protect whatever the floor or wall is made of.
> The thinking is proterction from continuous heat. 
> don't forget the wall clearance specifications too. 
> If you dont have the wall clearance  required in the specifications for the particular heater, you then have to treat the walls. 
> these days all wood heaters should come with a wall clearance and heath specification, although some local authorities may require more. 
> cheers

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## bcg

Hi all, 
I'd like to chime in and ask if anyone has any experience with hearths for pot belly stoves. I thought the flue install was going to be the tricky bit but it seems the hearth is the difficulty on these beasties. I found an old install manual for the Masport potbellies and they recommend two sheets of "Micore 160" topped with a sheet of tile underlay then tiles for a hearth that can sit directly on the floor. Does anyone know what the modern equivalent of "micore" is? Or, any other recommendations based on experience for these heaters that get damned hot underneath? 
Failing that, I know 50mm of slab suspended 25mm over the floor will do the trick but it will look bloody awful. 
Similar to the OP I'm on cypress floors. 
Cheers,
Brad

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## Moondog55

Micore seemed to be a vermiculite plaster sheet product.
I'd be using compressed cement sheet on the floor, topped with bricks, those old fashioned pot-bellys radiate a LOT of heat straight down, also I would get a sheet of stainless steel or heavy gal plate that would fit between the legs and under the unit, drill holes in the 4 corners and use a 100mm bolt and 2 nuts in each corner as a heat shield

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