Floor blocks spreading?

[robertjusher]

HI
I have had my 900mm homebuild firebrick oven up and cooking well for 6 months now. Cooks great.
However the firebrick floor was set with no gaps between them and now the ash has gotten between the bricks and seems to be spreading the bricks apart. The bricks were laid on hebal with fireclay as listed in the plans.
The gaps seem to be getting bigger and a CRACK IS NOW FORMING in the dome in line with the biggest floor gap.

Can this be stopped?
Can i clean out all the ash from the gaps and fill it with hi temp morter etc to stop this.
I am concerned if the dome cracks then the insulating blanket fibres could enter the dome during cooking. Idid not cover the dome in al foil before insulating as I did not want to trap water in.
Any thoughts?
Rob

[brickie in oz]

Re: Floor blocks spreading?

Can i clean out all the ash from the gaps and fill it with hi temp morter etc to stop this.

The ash is filling the expansion in the joints between the firebricks, not causing the problem.

[robertjusher]

Re: Floor blocks spreading?

HI and thanks Brickie
Do you think this will settle down and the crack will stay the way it is?
It's been the same size for a while now and does not effect the cooking ablity in any way.
I love my new oven and would hate to have to rebuild it.
I get people ask when are they getting invites again !!!
Rob

[Laurentius]

Re: Floor blocks spreading?

Could the hebal, be causing the problem?

[david s]

Re: Floor blocks spreading?

Don't worry about the gaps in the floor bricks, they allow for expansion and will fill with ash. Just leave the ash in there. Regarding the dome crack, it is just your dome finding its "comfort zone" from the expansion and contraction cycles. They usually don't get any worse, but if it's bigger than being able to fit a playing card in it you could try to fill it. It is usually only partially successful though. You may be right the expansion and contraction of the dome against the blanket could abrade it and some fibres could find their way into the oven. The fibres are only dangerous to inhale not to ingest. To plug the crack dampen around the crack, wait a few minutes then try squishing in a mixture of equal parts fine sand, fireclay and lime.