Glass Bottles in Perlcrete layer

[alexlea88]

Afternoon all

This has probably been asked many times before, but I can't see a definitive answer. Is it okay to put glass bottles in the perlcrete layer, or will it affect the evenness of the floor temperature?

I'm using a sleeper box base which I've filled with bricks 3/4 full, then a 4" concrete layer which I'm topping with perlcrete which I'll build my oven floor on. I've put down about 1-2" but it's slow progress and I still need another 3-4 inches or so. Can I embed some glass bottles to help reduce the amount of perlcrete I need and if so, do I need to use a full layer, or can I put some around the edges/ around the door area and leave the perlcrete for under the actual floor? Is it better to just bite the bullet cost and time wise, take my time and use 100% prelcrete?

Many thanks in advance

[UtahBeehiver]

I have seem some old school uses of bottles how effective they are for insulation is uncertain. Pecrete at a 5 to 1 ratio, no sand is the standard for floor insulation, a min, of 4" thick. See attached table. IMHO, perlite, at least in our area is relatively cheap in the scheme of WFO oven costs.

[alexlea88]

I have seem some old school uses of bottles how effective they are for insulation is uncertain. Pecrete at a 5 to 1 ratio, no sand is the standard for floor insulation, a min, of 4" thick. See attached table. IMHO, perlite, at least in our area is relatively cheap in the scheme of WFO oven costs.

Thanks for the reply and the advice. Yeah, I thought I might have to just bite the bullet! Just seems like a lot of extra perlite and mixing. A 100litre bag is only £30, but it all adds up. I also thought a few Peroni or Pinot Grigio bottles in the base would add to the Italian authenticity.