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Post by rnb1989 on Jul 1, 2017 23:17:00 GMT
Hi what's the recommend mix ratio and also has anyone got a link to some stainless steel needles/pins that would help binding process TIA
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Post by downunderdave on Jul 2, 2017 9:42:11 GMT
Hi what's the recommend mix ratio and also has anyone got a link to some stainless steel needles/pins that would help binding process TIA That would depend on where you are using the vermicrete. For under floor insulation you need it to be strong enough. The usual ratio for this is 5:1 by volume of vermiculite:cement. If you are using it over the dome (usually a layer over the insulating blanket that will even out the lumps and bumps), but just strong enough to act as a firm substrate to apply a rendered cement shell onto. This way the layer also works as additional insulation. I find a 10:1 mix is about as lean as you can go but still making a workable mix. The correct water addition is essential ie 10 parts vermiculite, 1 part Portland cement, 3 parts water, by volume. Also for every litre of cement added a small handful of powdered clay assists in making the mix more workable. Adding ss needles to a vermicrete mix is a waste of time and $/£ IMO because they are dense and conductive (the opposite of what you want in an insulating layer) and it's doubtful that they would increase the strength in such a lightweight mix anyhow. Better to use some polypropylene fibres if you want more strength without adding density or conductivity. |
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