Rendering over insultaion

[doncoyote]

How long does vermacullite cement take until i can render over it? Also would you render directly onto the vermacullite or use some wire mesh??

So close, yet so far....

Tom

[kstronach]

Hi tom.

If it was me I'd be tempted to leave it for at least a week or so and start small curing fires and make sure the vermi was completly dry before rendering. As the vermi holds alot of water and I wouldnt want the risk of the rendet cracking when moisture was trying to get out from the layer below. Just my opinion there's probably others who have rendered it the next day! I didnt actually use vermi I went straight on to the blanket so im sure someone else will chip in who has done it that way who may advise better.

Yes you can render straight on to the vermi.

keith

also if you do leave it to cure if its forcast rain get it covered over you dont want it getting wetter that it already is.

[cannyfradock]

Hi Tom

I think Kieth has answered your questions...spot on!! (and your last PM). "Yes you can render straight on to the vermi.".....and of course this could be done the following day, but as Kieth mentioned you need to get as much moisture out of the bricks, mortar and vermecrete before laying a fial waterproof render. Some of the WFO builders over on the American FB forum have put all the layers on in a short time and left a few small exhaust tubes sticking out from the blanket layer to allow steam to escape from the dome during curing.......myself I go with Kieth's recommend of trying to get as much moisture out as possible BEFORE sealing the dome with a waterproof render layer.

Terry

p.s.....if you get the chance, please post some pics....

[bookemdanno]

Yep, i concur.
Leave as long as possible, and use the oven a plenty in the meantime.
If possible, and better, erect a temporary structure over the oven, like a gazebo. It'll let the breeze get around your spherical.
I paid the price for rendering too soon, and had mini steam geysers erupting all over my new rendered dome.

[doncoyote]

Thanks for all the info, building that oven was like raising a child. I had a budget as we plan on leaving this house on a year or 2, we had time constraints.. (long story..) But today the last coat of render has been applied, just leave it to dry then white wash and a few finishing touches and the job is complete. We have already had 5 pizza sessions in 8 days with various friends and family events, all i can say is WOW.... The oven gets hot quick, (i concur with all reports that the most important thing here is good well seasoned hard wood...) The insulation is fine as 2 days later the internal temp is still 70degrees c, no steam geysers from my render (yet) Just a happy man...
I'll get some pics up

[cannyfradock]

Don

Great to hear that you're reaping the benefits from your hard labour. Next step is to get cocky......after your next pizza party rake out the coals/embers and chuck in a few loaves. If you haven't a door, then soak a piece of wood and press this against the entrance. This should take 35 to 45 minutes. When the bread is out......chuck in a slow roast for the next day's feast. If your oven has the correct insulation you should be able to bake a cake with the residual heat the next morning....or at the least...bake a few home made croissants....

Looking forward to those pics.....

Terry

[doncoyote]

Ha, already done Terry!! Next day roasts, breads, baked pots...... Loving it. My daughter invented a sweet pizza/calzone placing nutella, bananas and marshmallows on a thin pizza crust, folded into a calzone and fired for a minute or 2....!! Apparently its very nice. Had some sweet chestnut i cut down last year in the woodpile and roughly chainsawed a thick door with a thick inner door attached, unfortunately the inner door bit is now charcoal..... going to have to work on that one....