dry stack block stucco finish experience

[christo]

Hi - I'm getting ready to put the cement board on the housing for my oven.

I'm trying to decide if I should use a fiber reinforced surface bonding cement on the blocks or if I should run cement board down the surface of the block and finish with traditional stucco.

Has any one had any issues with stucco or fiber bonding cement cracking on a dry stack foundation?

I figure the fiber reinforced bonding cement may contain the block enough so it will not crack if I use it on the inside and outside of my block foudnation.

Thanks

Christo

[CanuckJim]

Re: dry stack block stucco finish experience

Christo,

In my experience, the stucco will stick even better to the block than it will to the cement board, but it will be thirsty. If the block is tinder dry, you might have to wet it with a paint brush a bit first to ensure good stick.

Jim

[Xabia Jim]

Re: dry stack block stucco finish experience

I wet my masonry with a hose before stucco work, but I'm using a cement sand mix stucco at about 1:4 ratio.

My last stucco was the easiest, as I finally made the mixture wet enough to just trowel on. Back side, seemed like 4 hours vs front side at 1/2 hour. A couple of hours later, I went over it with a sponge to get a nice even finish. You can make whatever texture you want though!

I think as long as your dry stack blocks are not going to move, the stucco will actually strengthen the mass.

[RTflorida]

Re: dry stack block stucco finish experience

Applied type S cement and sand mixture (1:4 ratio) to my block three weeks ago. Jim's experience is spot on. My block was tinder dry, I had a bucket and sponge - switched to the garden hose after the first wall. With the extreme dry conditions we have had as of late I would say my 1/4" skim coat has set up - no cracks.
As this will not be my actual finish (I will be using slate tile, cut to resemble bricks) I'm not too worried about any small cracks. This was just to seal the block in case of rain and from my sprinkler system.
I did attempt to use cement board joint tape on the block joints - failed miserably, would not stick to the block, and I kept pulling it off with the trowel, pulled the remaining strips of tape off, and "bare" skimmed all the block walls.