Huge crack on first use

[Genev]

Hello all, My new oven set for a week followed by 5 days of curing fires. Yesterday was the first go at pizza. Today I found a giant crack almost splitting the chimney area and running all the way up the dome. What do I do now? Is it as bad as it looks? This is the premio g100 kit.

[david s]

As it is an oven you've purchased rather than a home build your question should be directed to the manufacturer. The bad news is that it is not repairable unless the whole oven is replaced. The good news is that the oven won't collapse, the crack will not get any worse and the oven performance will not be altered.

[david s]

I did some repair work on a damaged oven yesterday. The inner oven is fine, but there is some severe cracking in the outer shell, around the flue and at the decorative arch. The problem is from water entry from around the flue the cracks in the outer shell and at the base of the dome and this water turning to steam. After over a week of unseasonal rain accompanied with extreme humidity a fair amount of water has got into the oven, particularly under the floor. The oven sits on a large slab of granite also cracked, which has been placed over 17mm exterior plywood which in turn sits on a galvanised steel frame. It seems like there's an inch of ceramic fibre blanket between the floor bricks and the granite slab. I drilled four 10 mm holes through the plywood which was quite wet once I'd drilled in 5mm. The cracks in the outer shell and base to granite slab were cleaned out with a wire brush and filled with flexible pointing as well as the outer arch. The area around the flue pipe was also cleaned out and filled with high temperature silicon.

[david s]

It probably would have been better to push out the water before these repairs, but the remedy now is a slow burn of 5kg bag of heat beads along with some kindling to keep them alight.
The poor design of this oven which does not incorporate an expansion joint between the outer arch and the inner oven parts, no steam relief vent or under floor weep holes has led to the damage. In addition the inadequate underfloor insulation and galvanised rather than stainless flue pipe are disappointing features. Pics show finished repairs.

[NateQLDer]

It probably would have been better to push out the water before these repairs, but the remedy now is a slow burn of 5kg bag of heat beads along with some kindling to keep them alight.
The poor design of this oven which does not incorporate an expansion joint between the outer arch and the inner oven parts, no steam relief vent or under floor weep holes has led to the damage. In addition the inadequate underfloor insulation and galvanised rather than stainless flue pipe are disappointing features. Pics show finished repairs.

HI David, What did you use to repair the cracks? Was that just a stucco mix?

Cheers Nate

[david s]

No, because a standard stucco mix will not expand and contract as the oven wil under heating and cooling. I use a product that was developed to eliminate the problems of expansion and contraction on the ridge caps on tiled roofs. It is basically an extremely elastic acrylic mixed with sand. This gives it the ability to be applied thickly and maintains an elastic waterproof seal ideal for bridging crack. In Australia it is known as Flexible Pointing. It is sold as a trowelable product and I also use it to coat the whole exterior of the cement rendered finish, but water it down 20% so it can be painted on. Three coats results in around a 1.5mm thick coating over the whole oven.