First time builder - lintels for hearth?

[RobDodds]

I'm just starting project for modular pizza oven. Have laid 8" thick reinforced foundation onto which I'll build concrete block base. My questions are to do with materials for hearth. I have concept of using concrete lintels 100mm X 65mm (4" X 2.5") laid between the concrete blocks then topped with 12.5mm Hardibacker board, then either making insulating layer of vericrete & CALSIL board or just CALSIL board without Vermicrete. I figure maybe I'll need 4 lintels to bridge the 1.2M square gap adequately. Does anyone have any experience of doing this rather than pouring concrete hearth? Are there any risks or potential poor performance with oven? Cooking surface will be firebricks.

Also thinking if I can use 140mm wide hollow dense concrete blocks rather than normal 215mm wide as they should be lighter to handle, with every other hollow filled with concrete - is this likely to be stable enough?

Thanks in advance for advice - don't want to screw up through trying something new.....

[Dagored154]

Re: First time builder - lintels for hearth?

Hi, I had the same idea to use lintels. after giving it lots of thought I believe it would work just fine. definitely put the concrete board on top of that and you should be good to go. the heat will never reach the lintels and so what if it does a little???? you will have the concrete board, FB Board and firebrick on top of them so it should never be a problem. I ended up not using lintels since I strained my wrist digging the foundation by hand and found that the lintels that long are heavy. my two cents is that it should work.

[deejayoh]

Re: First time builder - lintels for hearth?

I think Rob posted the same question on three forums at the same time. It was answered here
http://www.fornobravo.com/forum/f2/n...ase-17890.html

[RobDodds]

Re: First time builder - lintels for hearth?

Hi Dagored- I posted in several places as I couldn't really decide where the best place was to get some responses. From the replies it looks like newbies was the best. Thanks for your answer - it differs from most others who think that the only safe way is to pour solid concrete hearth - I still think the lintels would be strong enough and a darn sight easier but we're in the minority. For my first build I may finish up playing safe and pouring concrete.

I will post again when I decide and advise on the results.