External crack

[CanuckJim]

Re: External crack

All,

I don't think hairline cracks are much of an issue. BUT, exterior cracks on an igloo will allow moisture infiltration, and that is not a good idea. Wet insulators do not insulate. As well, if you've ever seen the face of a house brick that's gotten wet, then frozen, you'll know that the force of the freeze-thaw cycle will kick the front of the brick right off. It's called spalling. Once the cycle begins, in a brick wall or an oven dome, it's virtually impossible to halt. I'd recommend that significant exterior cracks be ground out in a V and filled for just that reason. XJs on the right track with a flexible material of some sort.

Ji

[talisker63]

Re: External crack

Thanks appreciate your support in these difficult times

The insulation material is vermiculite mixed with sand/cement over a blanket.

The top coat is tinted with oxide.

I think the top coat is too thin over the arch, this bit was hard to do and I may have skimped a bit on the thickness

I am having a big pizza party next weekend for Easter. Will report after that.

cheers

[Frances]

Re: External crack

Thats so funny, Jim! Great minds and all that, eh?

About the crack: this subject interests me greatly, as my render will be covered with mosaics which means I probably won't see the cracks if/when they form...

So is a crack in the outside render very serious? If some of you say you left the cracks as is? I thought that even a small crack could wick up enormous amounts of water every time it rains. What about tiling over the top, does that help at all?

Great pizzas btw, talisker!

[Xabia Jim]

Re: External crack

Then I read Frances post on her Ostrich......

No bacon today,
the bacon's gone away,
sad as it is to say,
the bacon's gone away

...sorry, I was out on the oven today and seem to to have got stuck in singing mode. Let me know what you think if you try it!

>
>
>

Frances, this is too funny.....

I think we were both humming the same tune!!

.....another FB cosmic connection

[Xabia Jim]

Re: External crack

Those pesky cracks

I think we're still looking for a dome that has not cracked. I would also be interested in hearing of someone has had good success with grinding out a crack and filling it.

With the continued expansion and contraction of these ovens and fireplaces, are cracks just a part of life?

I had an indoor fireplace and never was able to successfully fill an exterior crack on that one. (never ground it out though) And I do have two exterior cracks on my oven now. I've filled them a few times and painted over. Recently I tried an arcrylic caulk (more flexible).

Reminds me of a song....

Oh, the crack came back
It wouldn't stay away
The crack came back
The very next day

Dutch has it right too, give it time to grow (if it's going to) and stabilize

[gjbingham]

Re: External crack

I agree with Dutch. Did you add stain to the rendering material or did you paint afterwards?

If it doesn't get worse, I might be tempted to take a grinder and open the crack up and refill it again. I forget. What's the insulation like below this layer?

[Dutchoven]

Re: External crack

I might suggest using the oven for a while...maybe crack will stabilize...mark it with a pencil to see if there is any movement and watch it when the oven is firing and when it gets hot to see what it does...any widening and where etc...then you will have a better idea of what to do.
Dutch

[talisker63]

Oh no!

Fired the oven last night (see pizza photos in photo bragging section) but just as the fire was finished and burning down the oven render cracked. The crack is only in the final waterproofing render that i put on last weekend (7 days ago). So I guess I fired too hot - too soon

Also thought that maybe the render was too thin, only about 1-1.5".

The crack started at the flue and then slowly worked its way all the way down to the arch. It is only hairline down by the arch but about 1/16" up by the flue.

Any advice on how to repair?
Do I need to render the entire oven again or just the front section?\
If I leave the crack and tile the front would that work?

Help!

Thanks