How to finish the dome

[rans]

Hey all,
Since this is my first post on this forum after ~1 year of reading, I would like to start with some good words..
I never saw a forum that is so professional and people having so much patient and respect for other forum members (even new one like me..) , I'm almost finishing my oven and I could find an answer for any problem I had along the way. I guess I could have find the answers for the current question but I wanted to say my thanks.

Regarding my question,
I finished my dome, put the 3 inch blanket on top and thick chicken wire on top.
My question is how it will be easier to finish the dome and make it look round again (I'm building the egloo type)? shall I use the vermeculite concrete or can I use the render already?

If i'll avoid using the vermeculite concrete will I reduce the risk of humidity and cracks?
Can I use only the render for shaping the dome (I guess I'll need ~2 inch thickness in order to fix the bumps caused by the blanket and chicken wire)?

I'm sorry for the long post and my bad english..

Thanks again,
Ran

[Gulf]

Re: How to finish the dome

I recomend the vermicrete to get the insulation covered igloo back into shape. As far as the moisture issues are conserned, just let the vermicrete layer sufficiently dry before rendering. In your part of the world slowing down the rate of the drying process, to allow for proper curing, may be more of an issue than for most of us.
Welcome to the forum

[nissanneill]

Re: How to finish the dome

Hi Ran and welcome aboard.
I personally (as I did on my own Pompeii) is to put a good layer (or 2) of chicken wire over the insulation and put on at least a 2" layer of vermiculite cement as Gulf suggested.
It will allow you to generate the shape that you require, dry it with the normal curing method of fires and then put a thicker rather than thin layer of render to waterproof the dome. I even extended the roof of my outdoor kitchen to ensure that my dome remains dry.
All the best.

Cheers.

Neill

[rsandler]

Re: How to finish the dome

Hi Ran,

I was just asking the same question in another thread: http://www.fornobravo.com/forum/f9/c...cco-18682.html. The general conclusion seemed to be that vermiculite cement would be a good idea, but a thick layer of stucco would work if you add reinforcing fibers to the mix.

[rans]

Re: How to finish the dome

Thanks all for the quick reply.
I will go for the vermiculite/perlite concrete 8:1 as suggested, hopefully will get back with pictures..

Regarding the fast curing in my part of the world (Israel), It is very rainy during this season at my home so it won't be an issue..

What is the recommended perlite grain size for this purpose (I can't get my hand on vermiculite)?

[jab49]

Re: How to finish the dome

Hi Ran
I am at the same point, in Perth, Australia. I pretty much will do exactly the same thing. I'm covering with two layers of 25mm thick blanket, then vermicrete to get back to a round dome shape, then render the outside with, (I'm estimating), at about 1-2" thick render that has a waterproof compound in it. I will get the name of this material from my neighbour who is a plasterer and post it up in the next few days. My dome is half under a roof, half out in the open, so it needs to be waterproof.
Cheers
JT

[david s]

Re: How to finish the dome

JT,
If you plan on adding a waterproofing additive to your stucco layer then make double sure that you eliminate all the water from the vermicrete layer first as the waterproofing will lock any moisture in. I prefer to waterproof over the top of the stucco after about 10 decent firings after the initial curing. Better to be safe than sorry.

[Gulf]

Re: How to finish the dome

JT,
I agree with David. You may want to include a relief vent at the apex of your dome's render should you trap some mosture inside.

[jab49]

Re: How to finish the dome

JT,
I agree with David. You may want to include a relief vent at the apex of your dome's render should you trap some mosture inside.

Thanks - sounds like a good idea, because the vent will be out of the rain in my case. What form would this take - just place a plastic or steel tube from the outer vermicrete level and remove it once the render has set?

Cheers

JT

[Gulf]

Re: How to finish the dome

Thanks - sounds like a good idea, because the vent will be out of the rain in my case. What form would this take - just place a plastic or steel tube from the outer vermicrete level and remove it once the render has set?

Cheers

JT

Just about anything the right size will work .

[Gulf]

Re: How to finish the dome

I used the beer can to form a hole from the blanket layer through the vcrete layer. I don't have any pics at the moment but a 2" to 1" pvc reducer has been set into the stucco layer to recieve this vent.

The reducer will be hidden in a layer of brick splits which will cover the dome.

[waikato pizza]

Re: How to finish the dome

so did anyone find out the name for the waterproofing compound in Oz?

A friend reckons, the addition of dish wash liquid really help to waterproof concrete based products - is this a mythbusters investigation time?

[nissanneill]

Re: How to finish the dome

Bricklayers often add a little laundry detergent to their mortar which makes it more 'useable' but not more waterproof. The higher percentage of portland cemnt will do that!

Neill

[david s]

Re: How to finish the dome

A mixture of Silasec and portland cement is a good waterproofer.

[rans]

Re: How to finish the dome

Hey All,
It took me some time but finally I'm ready for the top coating of the dome.
As you suggested I used ~1-2inch vermicrete on top of the insulation blanket+wire.
now I have two more questions -
1. I finished the vermicrete ~2 month ago and the dome bricks ~6 month ago, can I haste the curing process (It is quite warm around here)? I guess that after so much time not much humidity left.

2. I want to use broken ceramic tiles on top of the dome (similar to the floor), is it recommended to put a stacco on top of the vermicerte before attaching the tiles?

Thanks