Hearth build up questions

[jmargush]

Getting ready to start my oven.

I am building a steel stand with hardi baker on top of that

Can I set the insulation board down directly on top of that?
Should it be mortored down?

Where can I look for a local source for this board? And what is the prior name of the board? Ceramic insulation board? Fiber insulation board?

[mrchipster]

Re: Hearth build up questions

Hardi is not strong enough to support the weight of the oven.

Insulation board does not need to be mortared down, just set in place.

These two questions lead me to, what size steel are you using for your stand and how is it constructed, ie welded, cross bracing etc.

Have you read the Forno Bravo oven plans?

Have you read all of these linked projects? a list of best of the best.

http://www.fornobravo.com/forum/f2/n...res-15133.html

[stonecutter]

Re: Hearth build up questions

Before you even get to structural limits, Hardie backer is not intended for exterior use.

[jmargush]

Re: Hearth build up questions

Steel frame is 11 gauge 1.5" square tube vertical legs on 20" centers.

then I will have an 11 gauge 1.5" x 3" tube running across to support the floor of the oven on which the hearth will set.

When I asked on the forum before about whether I needed to pour a slab on top of the steel stand several people mentioned that it was not needed and that a product like hardi backer or a cement board could be used.

If hardi backer holds up to bathroom shower installations and this build will be a house style of oven. Would it not work in this application?

[jmargush]

Re: Hearth build up questions

I have and am constantly rereading the Forno Bravo plans

[sharptailhunter]

Re: Hearth build up questions

Are there any particular reasons why you want to make your stand that way? For me, there is peace in knowing a masonry/concrete stand and hearth aren't going to rust or collapse, not mention thousands have been successfully doing it this way for quite some time now.

[stonecutter]

Re: Hearth build up questions

Steel frame is 11 gauge 1.5" square tube vertical legs on 20" centers.

then I will have an 11 gauge 1.5" x 3" tube running across to support the floor of the oven on which the hearth will set.

When I asked on the forum before about whether I needed to pour a slab on top of the steel stand several people mentioned that it was not needed and that a product like hardi backer or a cement board could be used.

If hardi backer holds up to bathroom shower installations and this build will be a house style of oven. Would it not work in this application?

Because HardiBacker is considered an interior product and not recommended for exterior work. Don't take my word for it, the information is on their website.

[NCMan]

Re: Hearth build up questions

If hardi backer holds up to bathroom shower installations and this build will be a house style of oven. Would it not work in this application?

Actually, speaking with firsthand knowledge and experience, Hardie Backer does not hold up well in bathroom shower applications. I have removed and redone a few showers done by others that used it (and nothing else) and it does not hold up well when exposed to moisture. The thing to remember is, that tile and grout are not waterproof, although some people still think that they are. Installers should always use some type of waterproofing membrane/materials when using cement board in showers. Actually, I use regular 1/2" drywall behind my shower walls, along w/waterproofing materials (I'll leave the brand names out). I haven't used cement board in shower applications in quite a long time. Granted, if someone does nothing to waterproof shower walls, I would agree that cement board is better than plain drywall. However,that is not the correct way to install a tiled shower. Hardie Backer is not waterproof and does not remain dimensionally stable when constantly exposed to moisture.