cosmetic crack question and 1 year report

[waynebergman]

Howdy all. Its been at least one year since I have visited this site. Want to give a report on my oven and post a question.
Oven has been working better than I could have hoped for. I have not done any bread but lots of pizza and Cast Iron pan meat fry's and what not. We use the oven about twice a week and are really enjoying it. I am currently designing a steel overhang for the area so the winter rains and cold will be kept off the oven.
My question is how to handle repairing of some cosmetic cracking. Inside of oven is just fine but some cracks on the outside I should fix before the fall arrives. One picture shows a design flaw on my part just above the oven opening I did not insulate at the front of the oven like I did in other places and I think heat has craked this. Not sure if I should fill with more mortar or a silicone of some kind. The other pic shows a lifting or seperating from one mortar to the base of oven. Not a heat issues here just a crack that I should fill but same question....should I use mortar or silicone of some kind. I hope my new roof will keep off the bad wheather but I should fix this now.....thanks in advance for any help. Wayne

[splatgirl]

Re: cosmetic crack question and 1 year report

I don't know about the crack on the oven itself...I think maybe you're fighting a losing battle to some extent with that one which would make me say caulk, but that's going to mess up your aesthetics quite a bit, IMO. Did you use mortar or grout on that portion of your cladding? Any modifiers like latex?

For the joint between your oven and the hearth slab and applying what I know about tile work, you should caulk that. Because it's A. a change of plane from the vertical to the horizontal, and B. two different materials with independent expansion/contraction properties, the flexibility and adherent properties of caulk are what you want. Cementitious products like mortar or grout aren't really adhesive in that situation, so basically I think you'd just end up with a chunk of material that fills the gap but eventually comes free from one or both of those surfaces because of movement or shrinkage and then there you are with the same problem. I think to be technically correct from a construction standpoint, you would have run flashing up under your oven cladding that skirted down onto the slab and then caulked it to the slab.

[waynebergman]

Re: cosmetic crack question and 1 year report

Thank you splat. No additives for my mortars. I dont really care about a blend in fix so much. Caulk would be my first choice. Not sure which product to use. Last spring I put some high heat silicone up above the entrance way and it kind of just flowed and washed away when I heated up the oven. Hope I can use the same caulk for areas effected by heat and the areas not effected by heat but I can buy two different products if this will be best solution. thanks again....wayne

I forgot to mention it was a type N mortar for my outer layer on oven dome that is holding the river rock in place. It is this type N that is cracking and needing the repair.

[RTflorida]

Re: cosmetic crack question and 1 year report

Wayne, nice to see that you are back. I wish I could help......but I have been fighting the same type of hairline dome crack as you. I too used type N to set my mosaic. I have ground it out twice with a Dremel, and it has come back within a few months each time.
Due to other recent water issues (rain driven by wind into the entry), I am currently "tarped" for the summer. made it 2 yrs without moisture problems, then 2 months ago my oven became a giant sponge after a week of freakish rains coming from the wrong direction. I'm actually trying to figure out a roof sytem that I can add on that will still allow the mosaic to be highly visible (a project for the winter).

I would try the caulk and see how it looks.....you can always grind it out and use mortar again if you don't like it.

RT