Weather proofing oven

[chukie]

Hi every one. I am new to this site, it certainly is very informative. My question is that I am planning to insulate the top of my oven with a vermicuilte and cement mix. Can you then directly weatherproof the top and sides by applying a stucco covering directly onto the vermiculite cement mix? Any help on this matter would be much appreciated.

Cheers
Chukie

[azpizzanut]

Re: Weather proofing oven

Hi chukie,

Stucco is not a good wet weather "proofer" for a dome. It will shield the oven from rain drops but not penetration of moisture. There are additional treatments you can coat the stucco with that help in that regard. Some builders don't worry too much about moisture getting into the inevitable cracks but others have legitimate complaints. Check your supplier for Bondall products.

The sides of my oven enclosure are made of moisture resistant cement board and coated with stucco. The surface is sealed with two coats of elastomeric paint. It is holding up very well.

Cheers,

[chukie]

Re: Weather proofing oven

Thanks very much Bob, I will look into your suggestions. I will ultimately cover the oven with a verandah over it, but that might take a while.

Thanks Greg

[GrahamG]

Re: Weather proofing oven

We put vermiculate V4 between the dome and the outer housing in between the fireboard. Then cladded the outer with marine ply and will add weatherboard on the outside.

Hi every one. I am new to this site, it certainly is very informative. My question is that I am planning to insulate the top of my oven with a vermicuilte and cement mix. Can you then directly weatherproof the top and sides by applying a stucco covering directly onto the vermiculite cement mix? Any help on this matter would be much appreciated.

Cheers
Chukie

[Neil2]

Re: Weather proofing oven

"Can you then directly weatherproof the top and sides by applying a stucco covering directly onto the vermiculite cement mix?"

If you go this route, go with an acrylic stucco. This material is more flexible and will more readily accommodate the expansion you get with the heating cycles.

Having said this, no stuccos are going to be 100% waterproof. I still cover mine with a tarp during the wet season.

[chukie]

Re: Weather proofing oven

Thanks everyone for your information. I like the idea of acrylic stucco. I will look at my options and report back how it works out. I will be enclosing the area with a colourbond roof, but it may be a while before that happens, so I want to weatherproof the oven in the meantime.

Cheers
Greg

[stonylake]

Re: Weather proofing oven

i finished my oven last fall, a 36" dome with an acrylic stucco. it's been raining for a month and a half here in Michigan, and i'm afraid that my oven is quite wet (some of it came through the flue). i will probably do 4 or 5 small curing fires before i cool with it again, just to make sure...

[chukie]

Re: Weather proofing oven

Hi Stonylake,

I,m still yet to weatherproof my oven, but getting very close to rendering. Must be disappointing for it to get that wet after all of the work that you put into it. We have a dry climate in Adelaide average rainfall is 520mm , but still plenty of rain to cause me issues.

Maybe you could further waterproof your oven. I'm going to add an additive to my render mix to help waterproof the dome. Through other members on this site I have been suggested to look at Bondall products for the weatherproofing. Bondall recommended 2 of their products to me Hydrocrete & Silasec. At this stage I think i will use silasec as an additive to the render mix - they say silasec if used properly can be used as a waterproofing paint as well. The other option maybe you could also think about is using elastrometric paint maybe a coating of this would help?

Good luck

[cobblerdave]

Re: Weather proofing oven

Dear Chucki
I finished my oven at Xmas time in QLD right in the middle of the big wet. Its a igloo so no overhead protection. I mortered over the dome insulatution and acrylic render paint over that. I then tiled the surounding slab and fitted a chimney cap.Still soaking wet and no cracks to be seen. Then I extended the entrance to protect the hearth bricks from rain and finally any bare brick ( I used old commons externally for appearance)were treated with bondall. Finally the oven remains dry seems in my case those old bricks wicked any moisture inside, were the firebricks and insulation just sucked it up . Like the wheather my was perhaps an extreme case but were still recieving weekly showers and the ovens dry now. Hope something here helps...

Regards Dave

[david s]

Re: Weather proofing oven

I think you can do everything to prevent water entry, but if it"s out in the weather ie. uncovered, your porous bricks are going to want to suck moisture from wherever they can get it. If the atmosphere is 100% humidity your bricks are going to suck water even though your oven is sealed. A fire the day before a big cook up is a graet help and if you've had months of rain, maybe a few gentle fires first.

[Neil2]

Re: Weather proofing oven

Getting some water in is not the end of the world. You just have to re-cure it a bit to get the insulation dry again. In my opinion, you can never get these things to be 100% waterproof and you are wasting your time trying to do something that is not that critical. Plan to manage for water occasionally getting into your oven.

One way of determining if there is water in your insulation layer is to check the external temperature of your dome during firing. The outside of a well insulated oven should hardly heat up at all if the insulation is dry. If it heats up much more than normal it may be because of steam build up.

In addition, I have a small (1 inch) vent in the top of my dome thru the stucco layer communicating with the insulation layer. Steam comes out of this in the spring (after not being used for several months) when I start firing it up.

[david s]

Re: Weather proofing oven

Neil, a vent that can release the steam is a good idea. I also have a system that vents the insulation area. I incorporated mine around the flue using two terracotta collars.

[dmun]

Re: Weather proofing oven

I incorporated mine around the flue using two terracotta collars.

That's a good idea. That joint is the Achilles heal of the igloo style enclosure.