First post, New build-- planning question

[DrScott]

I've been reading and learning here for years. Now we have moved to a place where I have room for the oven. I'm going to buy the CMUs today as most of the other construction around the planned oven is done....SWMBO has given her blessing for me to proceed with the oven. I plan to make up the base and frame the hearth as I dig the footer trench for her planting bed. Then I can pour both at the same time and since the cement volume will be greater I stand a better chance of getting it delivered.

When cladding the base with brick does there need to be an airgap between the CMUs and the brick? Further, since it will be enclosed and the "house" over the oven will be made from steel and cement board, do I need an airgap there? I plan to use metal tie straps to keep the brick up.

Is SS square tubing the best thing for a floor thermal break?

How do I attach corbels (is that the proper term?) to support the mantel outside the outer arch? I have not decided on material for the mantel yet. I may cast a concrete one, use granite, who knows.

[Tejaycar]

SS wouldn't provide much of a thermal break as it conducts heat really well. From what I've seen, most folks seem to use p/v-crete or fireplace gasket. I plan to use p-crete or a thin slice of CalSil with a little p-crete on top of it on the floor, and gasket on the sides.

As for cement delivery, you may want to look at u-carts too. They hold about 1 yard and can often be rented from hardscape companies. Cost comes out close to the same as for bags, but it's a whole lot easier.

[MarkJerling]

I've been reading and learning here for years. Now we have moved to a place where I have room for the oven. I'm going to buy the CMUs today as most of the other construction around the planned oven is done....SWMBO has given her blessing for me to proceed with the oven. I plan to make up the base and frame the hearth as I dig the footer trench for her planting bed. Then I can pour both at the same time and since the cement volume will be greater I stand a better chance of getting it delivered.

When cladding the base with brick does there need to be an airgap between the CMUs and the brick? Further, since it will be enclosed and the "house" over the oven will be made from steel and cement board, do I need an airgap there? I plan to use metal tie straps to keep the brick up.

Is SS square tubing the best thing for a floor thermal break?

How do I attach corbels (is that the proper term?) to support the mantel outside the outer arch? I have not decided on material for the mantel yet. I may cast a concrete one, use granite, who knows.

Welcome. I don't think you need an air gap, but from a practical perspective, an air gap would be good as it would help you to correct any out of square issues. I used ready-mix concrete too. So much easier than mixing it yourself. And (here by us anyway) the costs for delivered vs raw materials come out very much the same anyway.

[DrScott]

Thank you. I've started stacking the CMUs as a test build for the space before I start cutting them to fit. It will help me pin down the oven location and the hearth.

[NCMan]

Thank you. I've started stacking the CMUs as a test build for the space before I start cutting them to fit. It will help me pin down the oven location and the hearth.

Can you adjust your stand size a bit to avoid or minimize cutting of the block?

[DrScott]

I wanted to minimize the overhang of my hearth. Further, the blocks seem to vary in size between the 1/2 blocks and full blocks so I end up with gaps. 2 half blocks on top of a full block is too small by a mortar gap......

Is there an issue with cutting the CMUs? If the cavities line up to fill with concrete it should be strong for this application, shouldn't it??

[NCMan]

I wanted to minimize the overhang of my hearth. Further, the blocks seem to vary in size between the 1/2 blocks and full blocks so I end up with gaps. 2 half blocks on top of a full block is too small by a mortar gap......

Is there an issue with cutting the CMUs? If the cavities line up to fill with concrete it should be strong for this application, shouldn't it??

No, if that works for you, you can cut them.

[DrScott]

No, if that works for you, you can cut them.

Not something I WANT to do but definitely WILL do to get the desired outcome.

[NCMan]

Not something I WANT to do but definitely WILL do to get the desired outcome.

Are you laying the block in a normal way (w/mortar in the joints) or drystacking them? I've seen it done both ways.

[DrScott]

Are you laying the block in a normal way (w/mortar in the joints) or drystacking them? I've seen it done both ways.

I will have to mortar them to correct the slight slope to the foundation.

[DrScott]

I had the foundation poured along with a patio and the foundation to my shop. Thus I am dealing with a fixed size. It is 6" thick, reinforced concrete but slightly slopes away from the shop. I could probably compensate for it with the hearth pour but I'd like each aspect of the build to be as good as I can.make it.