How much Vermiculite for Base

[johnaero]

Oh going for a 4" base about 53" square.

Anyone know hoe may litres they used in past?

Rought work shows 185 litres but that means only need 2 100l bags and 2 25kg bags fondu to make the vermacrete

sounds like very little ingrediants

[turkey]

sounds a very very small base, I assume its actually 53' instead?

I used

www.pumpsandspares.com/volcalculator.htm

and used width and length of 7 feet which makes a total of 49 square feet, with the depth of 4 inches and it says thats 463 liters which sounds much more plausible.

Then we have the cement, I had a quick Google and a 25kg bag comes in a 33liters ish.

You then have to pick the ratio you wish to mix at, usual ratios are 1:6 or 1:8 as the cement will make part of the final volume but make sure you have spare as its not going to be as exact as vermiculite is slightly absorbent.

if using 1:8 then you need a third of a bag of cement for each bag of vermiculite, so a total volume if 111 per bag of vermiculite.

So I would expect 5 bags to be required to cover the whole base with 2 bags of cement.

I do not know if this changes ratio wise with fondu.

Also why fondu? is that not more expensive that regular cement? I do not see why you would use that?

you will need to run more specific numbers than the ones I have here prior to ordering but its good you checked as I think 2 bags as you suspects is off the mark slightly.

I used thermal breeze blocks as they were easier to calculate and quicker to fit, but casting this should be pretty easy work, just make sure you have something big and light you can mix it all in.

[tonyb]

John, your calculation looks right for the dimensions that you give (as is Turkey's). I think I used just under 5 100l bags of vermiculite, roughly spilt equally between the floor and a 50mm vermicrete layer on the dome of a 42" id wfo (apols for mixed units).

[johnaero]

well my slab is 53 inches x 53 inches and 4 inch thick.

oven is small as foolishly hadnt planned on making large dome. original plan was small vault.

kit they sell has 500l for base and 4" finished render and 5 dags 25kg fondu

i only need the base so worked it out and mine shows 184l as does you link you gave

cheers

[johnaero]

fondu and vermiculite is sold by local refactory at good price for ireland.

if i do not need fondu and cement will do for the base then feck that i wont use fondu. wasnt aware that could use a vermiculte/cement combo for base. just the vermiculate 6:1 i saw said use fondu but thats easy say when trying sell it to me

[cannyfradock]

John

I (actually...many of us) have used thermolite blocks as a thermal layer between hearth and slab. I only use vermiculite over the thermal blanket on the dome (vermecrete).....then for a 90cm internal diameter oven I find that 3 full bags is barely enough for a 3" layer.

Terry

[johnaero]

Ok so ill get extra as cheap. Cant find a dealer for thoes blocks o er here thats prob

[h12rpo]

Where exactly are you mate ? I assumed you were in Ireland ?? If so they stock celcon thermolites in jewsons

[johnaero]

couldnt find a shop for them in ireland

[h12rpo]

Deffo one in stranraer

www.jewson.co.uk/branch-locator/?Location=belfast

[johnaero]

still other side watre. what has shown is closest one which is as the crow flies across the sea

[h12rpo]

Oops sorry
www.quinn-lite.com/

Is a better bet

[johnaero]

hmm interesting. he is bankrupt so must see if that part of the quinn group still going cheers ill ring in morning

[turkey]

thermalite is a brand but any similar product would be suitable, any builders merchants and even high street diy chains (we have wickes and b and q here) stock them, they are the bread and butter of building blocks for new houses as they are strong and insulate well.

they are probably referred to generally as aerated concrete blocks, or breeze blocks. ?

can be cut with a wood saw as well which makes them very easy to handle.

[johnaero]

ah breeze blocks?

excrement these are cheap as piss