Insulating Slab

I poured the insulating slab today.  16 cubic feet of perlite to a little more than one bag of Portland cement.  I think that ratio is in the neighborhood of 8 to 1, just from eyeballing the size of the bags.  We’ll see how well it turns out.  It’s a good thing I was prepared by seeing several posts saying, “Don’t worry if it looks like it won’t hold together.  It will hold.”  My mix certainly looks like it won’t hold together.  I wetted it until it made a slushy sound while mixing, and I could squeeze together a snowball of material and it would hold its shape.

Super Isol is the way to go for the insulating hearth.  It would have taken 30 minutes instead of four hours (I ran out of material and had to go back to the store).  It also would have taken $250 (delivered) instead of $125.  I’m trying to keep the costs of this one as low as possible.   The main goal is to have fun and accumulate knowledge.   When we build our dream house in 10 to 15 years, I’ll know what to tell our contractor.


One response to “Insulating Slab

  1. Hi Chris,

    re the calcium silicate insulation (Super Isol, CalSite etc.): my refractories supplier assures me that one layer of 2.5 cm (one inch) is sufficient, everything else would be overkill and a waste of money…

    So my order contains 2 sheets 1100 mm x 600 mm (from memory) costing $A84 together. This is supposed to cover the base of a 1m round oven with its cooking floor built from 25 hearth bricks measuring 230 mm x 230 mm x 50 mm.

    Just thought I’d let you know…

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s