Durock for leveling insert?

[jophysx]

Is there any reason not to use a couple of layers of Durock or something similar on the bottom of the fireplace firebox to make a level surface with the exterior so the insert can be easily slid in and out? We have a raised hearth and the installer just used a couple of bricks to level the insert. It's awkward to get it in and out as is. Plus I like the idea of some extra insulation. Anybody have a better idea? The installation manual refers to leveling screws, but I don't know where those are. And the leveling screws would probably not be as simple as just a level surface to begin with.
-Jim

 

[Grisu]

Should not be a problem as it is a common non-combustible hearth material but I am wondering what's the need for pulling the insert out regularly?

 

[jophysx]

I've pulled it out to install a block off plate and then again to put in some insulation. I took those opportunities to clean the flue and decided that's an easy way to do it in the future.

 

[jatoxico]

Used Durock exactly as you showed. Worked perfectly and allowed the leveling legs to do what they are meant for, small adjustments.

 

[jophysx]

and I like the idea of insulation between the insert and the floor. After seeing significant improvement in stove performance upon adding a block off and insulation, I am on the camp of "the more insulation the better". It keeps the heat in the firebox and into the house.

 

[jophysx]

Used Durock exactly as you showed. Worked perfectly and allowed the leveling legs to do what they are meant for, small adjustments.

Right on about the small adjustments. With my current setup I would have to extend the leveling legs about 2.5 inches. I'm not even sure they're that long. But even if they are, that much length puts a lot of torque on the mounts. I would be afraid of breaking them right off if I tried to move the insert once installed. So I'll go buy some Durock tomorrow and go ahead with the plan.
Thanks for the replies everybody.

 

[cableman]

I just did mine with hardie board, seems a little more durable. I figured the insert would less likely dig in while sliding it in.
I mixed up a real watery mortor mix and floated it level.

 

[Swedishchef]

Durock will work in this case.

Levelling legs are for minor adjustments..I am pretty sure they're not 2.5 inches long.

Andrew

 

[fire_man]

I just did mine with hardie board, seems a little more durable.

I hope this does not start one of those "hardi-backer vs Durock" Threads. Nothing wrong with the hardi that I can tell. It's non combustible and as long as "R" value requirements are met, it should be fine. Yea Yea I know about the cellulose but it's still rated non combustible.

Can James Hardie products be used around a masonry fireplace?
Yes, HardieBacker® 1/4" Cement Board is deemed noncombustible when tested to ASTM E 136 and can be used in conjunction with other noncombustible materials around a fireplace. This does not mean that clearances to combustible building materials can be reduced by using HardieBacker 1/4". Clearances to combustible building materials shall be obeyed even if they are protected by noncombustible materials, please refer to your local building and fire code for specific combustible clearance details around masonry fireplaces.