Cinder block enclosure has cracks in grout lines

[sjdritz]

Hi,

A friend of mine just had a modular oven installed. The enclosure is surrounded with a cinder block structure and covered in stucco. The void was filled with a mixture of perlite and cement. Not sure the ratio. He is getting cracks all over the oven where the cinder block grout lines are. Also a few small ones in other places. Do you have any idea what could be causing this? It stared to happen with the curing fires!

Thanks,

Scott D.

[stonecutter]

Re: Cinder block enclosure has cracks in grout lines

Post some pics, that always helps with answering a question. It sounds like the cracking is because the stucco is bonded directly to the block, which will expand and contract differently than the stucco. I always have seen an uncoupling layer between the stucco and the wall. I'm no stucco expert though....

[sjdritz]

Re: Cinder block enclosure has cracks in grout lines

I don't have any photo's, but I could try and get some. The stucco coating is a smooth coat. If that matters. Thanks,

Scott D.

[stonecutter]

Re: Cinder block enclosure has cracks in grout lines

Outer finish doesn't matter.

[Les]

Re: Cinder block enclosure has cracks in grout lines

The void was filled with a mixture of perlite and cement. .

Not that this is causing cracks but why did he add cement at this point? To the problem; is the foundation sound? Since this is outside of the insulation heat should not be the cause (unless the ratio was WAY off).

[sjdritz]

Re: Cinder block enclosure has cracks in grout lines

The foundation is sound.

[david s]

Re: Cinder block enclosure has cracks in grout lines

If you mix cement with perlite or vermiculite then you also have to add a huge quantity of water. If the water turns to steam suddenly then rapid expansion takes place which can cause cracking. Adding cement to the mix will reduce the layers insulating capacity and the expanding steam problem both make a vermicrete mix problematic. If possible loose vermiculite is preferable like a situation where it is enclosed by a structure.