New Guy needs help

[TheBigC]

Greetings all,

I am building a 42" Pompeii. I poured the insulating layer of concrete. I followed the instructions mixing 5 to 1 vermiculite to Portland cement. Thoroughly mixed it dry, mixed it wet and poured. I screed it off. It has been poured for 4 days now. It set up well and is very firm BUT the surface has some give if I press my finger on it. Is that normal or have I done this wrong?

Advice please! Thanks in advance.

[Reg]

Re: New Guy needs help

BigC,

This is Reg, I just poured my insulating layer of concrete today and I'm experiencing the same level of uncertainty: that layer gives a little when pressed with finger. What did you finally discover after after your pour?

[TheBigC]

Re: New Guy needs help

Hi Reg,

I found out the the finished insulation layer should feel a bit like a cork. It give a bit when you press on it. It's edges also flake of and the top is easily gouged or marked. I used the mud (sand and fire clay) to even out the marks and lay a level floor. It has high compression strength. It's wired but it sounds like you are doing it right.

[TheBigC]

Re: New Guy needs help

Here is a picture of the oven floor and first course.

[TheBigC]

Re: New Guy needs help

Here is the just poured insulation layer

[TheBigC]

Re: New Guy needs help

Here is a close up of the dried insulation layer.