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-   -   Dry stack vs Mortar stack (http://www.fornobravo.com/forum/f28/dry-stack-vs-mortar-stack-10992.html)

PlanoPhil 02-16-2010 01:10 PM

Dry stack vs Mortar stack
 
What's the recomended method for placing the cinder blocks? I've noticed that some folks mortar the blocks in place and some dry stack.
Also, how important are the vertical rebar placement that are embeded in the foundation and pass up through the cores of the blocks? Again it seems that some do and some do not include them.

Phil

Les 02-16-2010 01:40 PM

Re: Dry stack vs Mortar stack
 
I dry stacked my block - it goes a lot faster. I put steel in the corners of the foundations of the island and a couple in the middle of the run. It may not be needed with all the weight but it will do no harm.

Les...

dusty 02-16-2010 06:32 PM

Re: Dry stack vs Mortar stack
 
I did exactly the same. I then filled every-other-one with concrete. I filled the rest with brick cutoffs and left over motar and stuff to keep the garbage can from weighing a ton.

dusty

Les 02-16-2010 06:49 PM

Re: Dry stack vs Mortar stack
 
Quote:

Originally Posted by dusty (Post 80911)
I then filled every-other-one with concrete. I filled the rest with brick cutoffs and left over motar and stuff to keep the garbage can from weighing a ton.

dusty

That's funny - thats where I put all the left over gravel/sand I was going to have.

Les...

kebwi 02-16-2010 07:03 PM

Re: Dry stack vs Mortar stack
 
I dry-stacked, but I don't have any rebar connecting the foundation to the walls (I didn't set any rebar sticking out of the foundation awaiting the wall placement), so the walls are effectively resting on the foundation, except for any "glue" effect between the concrete poured into the cores and the foundation.

I think that if you don't mortar the walls -- if you dry stack and fill the cores -- it is pretty important to put some rebar in the cores when you fill them...I guess, I dunno. I suppose it seems like filled cores are in a way stronger than mortared bricks since a filled core is basically a column of solid concrete.

Whatever, you'll be fine. Round up on the rebar. I sure as heck did. :)

Tscarborough 02-16-2010 07:11 PM

Re: Dry stack vs Mortar stack
 
Going by what I have seen here, 98% of the ovens are built atop bomb shelters. That is not a bad thing, but it can sure burn up excess time and money. Using calculated loads (leaving out seismic and frost issues), a pile of dirt is good enough for most ovens.

kebwi 02-16-2010 07:17 PM

Re: Dry stack vs Mortar stack
 
Agreed. When I first started my build, I ran some numbers and concluded that I could push against the foundation with my thumb harder than the pressure that would eventually result from the oven and stand. Run the numbers yourself and see what you get. It's a simple calculation. Weight of the stand and oven divided by the footprint of the stand (foot print of the concrete blocks plus the foot print of the filled cores). You will be surprised how low the load really is.

Les 02-16-2010 07:28 PM

Re: Dry stack vs Mortar stack
 
Quote:

Originally Posted by kebwi (Post 80919)
I ran some numbers and concluded that I could push against the foundation with my thumb harder than the pressure that would eventually result from the oven and stand.

I totally understand. I live in a state that is 3rd or 4th in seismic activity. I went with the fact that if everything would bounce and shift together, I had a better chance of survival. Rebar is really, really cheap, compared to the rest of the build.

Tscarborough 02-16-2010 07:34 PM

Re: Dry stack vs Mortar stack
 
Seismic and frost are totally different issues. For seismic, each unit needs to be tied together, and the important strengths are not compressive but bond and shear. For those situations, you need a bombshelter, because you have a heavy load subject to lateral movement.

For frost, you have to create a foundation that is able to withstand heave, i.e. extend below the frostline and be able to counter lateral stresses in the foundation. Above that, however, the stresses are normal.

fxpose 02-17-2010 10:00 AM

Re: Dry stack vs Mortar stack
 
During the '94 earthquake we had here, a row of queen palms in large 30" terracotta planters on our driveway bounced and shifted a couple of inches. It's easy to tie the stand to the foundation but what about the oven to the hearth when the next big one hits?


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