Firebricks disintegrating - UK build - Advice needed!

[2793david]

Hi Everyone

I built my oven around 6yrs ago now - I did a lot of research beforehand and FornoBravo was excellent in providing advice and guidance. We've had loads of fun with the oven over the last few years.

A couple of years after building the oven, I noticed that the internal archway firebricks were starting to disintegrate at the edges.

Ive attached a pdf with Photos

Ive had a lot of efflorescence from the fire cement which has resulted in white blooms which i have brushed away before each use, and this has mainly been in the entrance to the oven below the chimney. This has meant that the surface of the fire-mortar has largely disappeared in this area. Over the last couple of years have also started noticing 'stalactites' of grey matter forming on the inside of the oven dome from the mortar joints.

My main concern has been the disintegrating bricks of the arch. I have thought that this may just have been down to the damp UK weather and have made a front cover to keep the rain out. I don't think rain is getting into the structure through the dome as i made a layer of waterproof render under the bricks, and have also added waterproofing to the layer of bricks. I have also thought of making an outside roof to cover the whole area including the oven.

Do you think this brick break-down is due to damp? I was going to repair with fireproof mortar rather than replace full bricks....

Thanks

[deejayoh]

Hey David - Looks to me from the pictures like you have a water problem in the entire oven. Your brick cladding on the dome isn't going to keep water out, it's porous. I think that's the source of the efflorescence. I suspect that the water damage combined with the heat is what is breaking down the Arch. That's probably the hottest part of the oven, and with the water and heat you are going to get spalling. You need to keep that oven covered from the rain (trust me, I know, I live in Seattle!)

[2793david]

That’s really good advice, thank you. Maybe the layer of waterproof render has cracked with the heat and is letting water through as you say - sounds like I need to be thinking about covering the whole oven over.

thanks for the reply