[Balty Knowles]

Thanks Jim, I'll do that. You can barely see the cracks unless I dampen down to highlight them.

With regard to pouring into a form, thanks for the idea, I think it would be great for the insulation as well.

I'm very short on insulation space & only have 3 to 4 inches from the dome to the brickwork. See pics. I will extend the brickwork up from the stand to form a round tower built into the retaining wall.

If I place the insulfrax around the inside face of the brick housing & partially fill the space left in the center with vermiculite concrete I think It'll reduce some heat from the floor leaking under the blanket & also keep the blanket flat up against the face of the brickwork.

Regards

Balty