Insulation Efficiency

[brickie in oz]

Originally Posted by vtsteve

It sounds like a *good thing* for those of us in wetter climates. .

Not only for the wetter climates but for anywhere, even dry climates need a dampcourse, DPC.
Damp or moisture will climb and masonry structure so an impervious barrier need to be incorporated in to the masonry.

The rule of thumb is taken that rain will hit a hard surface and bounce about 100mm high, so the DPC needs to be set more than 100mm from the hard surface to stop moisture penetration up into the structure.

If the DPC is set too low it will be ineffective.

[vtsteve]

Ahh... I see, it involves drilling a continuous series of holes in the masonry and filling them with a silicone fluid, which permeates the masonry and forms a water barrier. It seems to be a UK/Oz technique.

[brickie in oz]

Originally Posted by vtsteve

Ahh... I see, it involves drilling a continuous series of holes in the masonry and filling them with a silicone fluid,

No, it involves putting a barrier in place as you lay the blocks.
Like this.

[vtsteve]

Thanks for the pictures - I guess Google was just showing me the repair/retrofit version. So, for the usual filled-core stand, you'd have to put down at least one course (~200mm) of block, fill and rebar the cores, put the membrane down (with the rebar punched through and possibly sealed), and add courses to reach your finish height. Have I got it right?

[brickie in oz]

Cement rich concrete should by itself be waterproof, you can also add a chemical waterproofing agent to the concrete which would probably be a better option.

My first suggestion was more for brickwork.

[v12spirit]

Originally Posted by dmun

"Rockwool" is a term we don't use in the US. If it's domestic insulation, like fiberglass, it may have organic binders that will burn and stink at the right-next-to-the-dome temperatures. Before you get too far, heat up your kitchen oven to 550 degrees f. (288 degrees c.) put a chunk of the rockwool in, and see if it stinks up the place.

If it's a refractory insulation, you should be good to go.

Rockwool is an alternative to mineral wool which is a lightweight fibrous material made from slag or glass. What is the difference between this and ceramic planket insulation?

[david s]

Ceramic fibre blanket is made from fibres that are made of clay.

[alex.g]

Originally Posted by brickie in oz

The way you have it there is no adhesion between the blocks and the concrete due to the rubber matting, plus when it rains the water will sit on the rubber matting and travel up the blockwork into the oven.
I can see in the pic that moisture is already travelling up the blockwork.

Any dampcourse should be well above ground level to stop this from happening..

bottom will be covered by rubber matting inside and outside, so there will be no water coming into foamblocks. Will post update

[BobGer]

Likely covered in previous posts, but haven't found it - question about the order of layers: on top of firebrick, which I was going to cover with high temp mortar, I was going to then cover with aluminum foil, then the FB blanket (3 inches), then a layer or two of vermiculite concrete, then a final coat of some waterproof stucco. So my question is whether putting the blanket first is appropriate or is it advisable to first put the vermiculite/concrete down? Or does it not matter? Thanks

[vtsteve]

Put the blanket on first. You want your most efficient insulation closest to the hot zone of the oven.