hearthstone homestead hearth pad

[yotehunter]

new to site. I would like to keep my hearth pad as thin as i can. My pad will be 74"x44" so I was thinking 1/4 durock screwed to sub floor than build a 1" metal frame from 1" square tubing with studs 10" OC than put Roxul comfort batt r-15 cut down to 1" thick to put between the metal stubs than 1/2 durock over the metal frame and 3/4 quartzite to finish it off.

I called roxul today and they side 1" of comfort batt has an r-value of 4.1

My stove has the 6" legs so i need 2.5 for r-value.

So from what i have this should work right?

Thanks for the help.

 

[rwhite]

Durock is not strong enough without an underlayment of at least 1/2". I would go 1" underlayment if it was me. Then you need the correct r-value between the stove and the underlayment.

Sorry just re-read your post. I'm not sure if the 3/4" stone will support a stove without underlayment

 

[yotehunter]

so if I put the 1/2 durock to the metal frame which will have 10" on center studs the 1/2 durock will not be able to support the thin set and 3/4 stone?, I also do plan on running 1x2x.120 wall rectangle steel tubing in the frame for the studs and right where the stove legs will set. I was hoping I could use the roxul as the underlayment between the metal studs and under the 1/2 durock. Thanks

I found this early today where the guy used metal studs with roxul between the studs and 1/2 durock over the metal studs. Was hoping to do the same thing only using structural steel tubing as my frame

https://www.hearth.com/talk/threads/homestead-hearth-mount.93956/

 

[georgepds]

Sister the studs with 2x4 then place 3/4 plywood level to top of studs
Now you have a solid base.. lay up the durock and insulating board on top

 

[yotehunter]

georgepds I have to keep the pad less then 3" tall. that why i was hoping i could us steel tubing as the frame and roxul as the main r-value with couple sheets of durock.

 

[dmarr]

Just went through this ourselves. It sounds like your plan will work as far as R-value, but may not be able to support the weight of the stone and stove. Durock is not strong enough to double as an underlayment. I used multiple layers of 1/2" Durock over 3/4" plywood to get to the required R-Value. Final height (if I remember correctly) was 3 1/2" with the porcelain tile.

 

[rwhite]

My hearth extension is free floating and maybe just under 3" thick. Laminated 2 sheets of 1/2" plywood, then 2 sheets of micore 300, then 1/2" durock, then tile. Not sure how to stay thin without using Micore or a similar product. I scavenged micore from a cubicle wall that I got at the salvage home builders store. Pretty sure the durock is not stong enough though. You might also search the r-value for vermiculite concrete. If it was high enough you could frame a 10x10 box under where the stove feet will sit and pour it in there. That way at least the feet would have a solid base.

 

[yotehunter]

dmarr, would it help if I made my studs 8 on center? that way the 1/2 durock would be only span 6" between stubs as my studs will 1x2 tubing. also lowes has 5/8 durock could try that?

rwhite, i planned on running metal studs right under the stoves legs to support the stoves weight. so i hoped the weight would transfer through the durock onto the metal studs.

 

[dmarr]

dmarr, would it help if I made my studs 8 on center? that way the 1/2 durock would be only span 6" between stubs as my studs will 1x2 tubing. also lowes has 5/8 durock could try that?

rwhite, i planned on running metal studs right under the stoves legs to support the stoves weight. so i hoped the weight would transfer through the durock onto the metal studs.

As rwhite said, to get a thin you need to use Micore or similar. I don't think the Durock will be stable enough even with reducing the span. It just isn't designed to be used as an underlayment.

 

[yotehunter]

going to go with 6" on center and 18 gauge sheet metal on top of the metal frame than 1/2 durock