Floor Protection?

[jmartie13]

I'm sure this topic has been beat to death. But, I'm looking for assurance regarding my situation. I have an old Fisher Mama Bear wood stove. I found an old manual for a similar stove that called for 3/8" Asbestos mill board for floor protection.....probably not going to find any of that, ha. I have two 4' by 2' slabs of slate that are 1.5" thick. I don't think I should put these directly on the wood floor? I was thinking of I could put a piece of 1/2' Durock under the slabs of slate? Or maybe a piece of sheet metal? Just trying to make something work for this year until I can build a permanent hearth.

Cheers! Joe.

 

[johnpma]

Tractor Supply

 

[webby3650]

I would not use the tractor supply board. They are very cheap and curl up on the corners in a very short amount of time. I'd use a piece of micore, then put your slate on top of that. Micore is very similar to asbestos, but without the obvious health issues.

 

[begreen]

You want something above an R=.52 rating. Use two sheets of Durock NexGen under the slate and you should be ok. A 1/2' layer of micore would be very good protection too.

 

[jmartie13]

Thanks for the info! Just curious, where did you get the R-value of 0.52?

 

[johnpma]

I would not use the tractor supply board. They are very cheap and curl up on the corners in a very short amount of time. I'd use a piece of micore, then put your slate on top of that. Micore is very similar to asbestos, but without the obvious health issues.

Really???? Mine didn't 2 1/2 years now

TSC Imperial Stove Boards are constructed of Micore 300 with a layer of sheetmetal over the Micore 1/2" has a K=.458 R=1.09 They are not bad for the money and are usually in stock

 

[begreen]

Thanks for the info! Just curious, where did you get the R-value of 0.52?

I should have said ~.53. It's actually .525.
https://www.hearth.com/talk/threads...d-what-is-the-equivalent.146277/#post-1969582

 

[begreen]

Really???? Mine didn't 2 1/2 years now

TSC Imperial Stove Boards are constructed of Micore 300 with a layer of sheetmetal over the Micore 1/2" has a K=.458 R=1.09 They are not bad for the money and are usually in stock

Good to know, thx. Is the metal heavy enough to avoid denting under heavy stove feet?

 

[johnpma]

Good to know, thx. Is the metal heavy enough to avoid denting under heavy stove feet?

Guessing I'd say the metal is around 1/16" thick not sure the R value of sheet metal I set my stove on 4 fire bricks on top of the metal

 

[begreen]

That's not too bad. I would probably put down some metal pads to spread the load a little under the feet. Metal is not an insulator it's a conductor. It's the micore that's doing all the heat protection.

 

[johnpma]

That's not too bad. I would probably put down some metal pads to spread the load a little under the feet. Metal is not an insulator it's a conductor. It's the micore that's doing all the heat protection.

So the metal acts as ember protection? If a stove was sitting on a stove board like this and ther was a 6" air gap between the stove and stove board is there a way to calculate what R the air gap offers???

 

[webby3650]

Really???? Mine didn't 2 1/2 years now

TSC Imperial Stove Boards are constructed of Micore 300 with a layer of sheetmetal over the Micore 1/2" has a K=.458 R=1.09 They are not bad for the money and are usually in stock

Ya I'm very familiar with them.
We change them out for real tile type 2 hearth pads pretty often.

 

[webby3650]

I'm almost certain it's 24 gauge metal. The weight of the stove smashes it where the legs sit. Then the edges curl up, debris gets under and it's a toe stubber. It might work ok for a pedestal stove or a small stove.

 

[begreen]

So the metal acts as ember protection? If a stove was sitting on a stove board like this and ther was a 6" air gap between the stove and stove board is there a way to calculate what R the air gap offers???

Correct, ember protection and stiffness are the purpose of the metal top layer.

The air gap will have an insulative property, but under the stove one also has to account for the heat radiated off the stove through that air. The taller the legs the weaker the radiant heat will be on the hearth.

 

[begreen]

I'm almost certain it's 24 gauge metal. The weight of the stove smashes it where the legs sit. Then the edges curl up, debris gets under and it's a toe stubber. It might work ok for a pedestal stove or a small stove.

24 ga is thin. It's probably working out for john because he is using bricks to spread out the weight of the stove. For folks in a tight budget scenario at least they are getting some decent protection as long as they know to put a load spreading pad under each foot of the stove. Still for the price one could build their own and have a more solid tile topped foundation.

 

[Highbeam]

If a stove was sitting on a stove board like this and ther was a 6" air gap between the stove and stove board

It sounds like you are trying to count the R-value of the air gap between the stove and the hearth (leg height) towards the R-value requirement. You can't do this. That distance is already accounted for when the R-value requirement is calculated. You provide the R-value below the bottom of the legs.

 

[jmartie13]

I ended putting one of the TSC Imperial boards underneath the slate and shimmed the corners of the slate where it overlapped the stove board. . This should give me plenty of insulation for this year. Thanks for all the info.