Continued Design Ideas

[Tscarborough]

Re: Continued Design Ideas

Normally you adhere the veneer with corrugated brick ties laid in the joints of the cmu.

Coursing may or may not be an issue, it depends upon the brick. In the typical 4 CMU high base, no mortar joints means you lose 12/8ths (1-1/2") If using a modular brick, you have 11 or 12 joints to make it up, IF you need to keep it coursed. Normally you don't, because you are pouring the base and thus can (and usually should) bring the brick up to finished floor (of the base), not the top of the CMU.

I would not recommend dry stack CMU unless you are stuccoing the base, as it needs the stucco for strength anyway. Normally it is call surface bonded CMU, FYI.

[clofgreen]

Re: Continued Design Ideas

Do I need to maintain a 1" air space between block and brick or can I lay the bricks against the block with some mortar to help them stick. Of course, I'd still use the brick tie. From what I've read, the air space is to help drain off moisture and to allow space for insulation, neither of which really apply.

[Tscarborough]

Re: Continued Design Ideas

You do not need the airspace, but if you don't leave a little gap you will have a hard time getting your wall flush and plumb.

[clofgreen]

Re: Continued Design Ideas

I'm close to starting my build but have one lingering question that I can't decide upon; whether to build a foundation below frost line or to go with a slab on grade. Our frost line is two feet.

My neighbor the professional builder said that for something small like the oven a slab on grade should be fine given that the soil here is quite sandy and well drained. My father in law who lives nearby said he would for sure build the foundation. It seems the concensus on the forum is for a slab.

I was leaning toward slab but decided to test the soil and had to dig down through ten inches of garden soil and then another foot of quite loose sand to find undisturbed soil (hard compacted sand and some clay). So my first question: Can I build up and compact the soil good enough to do a slab? What would be the best way to do that?

My second question: I've collected 40 6x8x16 CMU blocks, 20 10x3x16 concrete slabs, 53 10x8x16 blocks and 18 80lb bags of conc mix (all free of course). If I dig down to the undisturbed soil, lay the concrete slabs and build a two course CMU wall on top of them and fill the hole with good compacted soil and six inches of gravel at the top, can I pour my slab over that? Would that be better than just a slab?

Thanks, Craig

[Tscarborough]

Re: Continued Design Ideas

Yes, that sounds like the most reasonable use of the resources at hand.

[mrchipster]

Re: Continued Design Ideas

My second question: I've collected 40 6x8x16 CMU blocks, 20 10x3x16 concrete slabs, 53 10x8x16 blocks and 18 80lb bags of conc mix (all free of course). If I dig down to the undisturbed soil, lay the concrete slabs and build a two course CMU wall on top of them and fill the hole with good compacted soil and six inches of gravel at the top, can I pour my slab over that? Would that be better than just a slab?

I would go to HD and get 3 or 4 - 8 inch concrete tubes they come in 4 ft lengths, dig 6 - 8 holes cut the tubes in half and evenly disburse them under the future slab. Run some #4 - 1/2 inch rebar down into the tubes before your pour.

That will give you lots of below frost line support. and not cost much. and it is relatively easy to dig an 8 inch - 2 ft deep hole. We have to go 52 inches here in Minnesota.

BTW I am jealous, I need to get on a plane to ski Snowbird, Alta, Solitude, Brighton, Park City, Canyons, and Deer Valley.

Chip

[dmun]

Re: Continued Design Ideas

If it's not taller than you are, or part of an existing structure like a house, a slab on well drained gravel is fine. Personal opinion: I think sonotube protrusions under a slab just give the ice lenses something to grab onto. Sonotubes should have footings like any other type of foundation.

[Derkp]

Re: Continued Design Ideas

Craig,

I went the slab on grade route. Ours is at least 6 inches and we went overboard with the rebar. We used what rebar we had around, 1/2 and 5/8. we also placed some 5 or so inch square fencing material in the mix, suspending it in the slab. Almost 2 winters and no heaving, cracks, or anything.

Derk

[clofgreen]

Re: Continued Design Ideas

Once again thanks for the good advice. After talking to a structural engineer friend I've decided to build a foundation. One of the original reasons for wanting a WFO was for emergencies. Utah is overdo for an earthquake and I live just a few miles from a major fault so building it on the beefy side wouldn't hurt.

[Aegis]

Re: Continued Design Ideas

Once again thanks for the good advice. After talking to a structural engineer friend I've decided to build a foundation. One of the original reasons for wanting a WFO was for emergencies. Utah is overdo for an earthquake and I live just a few miles from a major fault so building it on the beefy side wouldn't hurt.

I am not a structual engineer, but wouldn't the foundation connect the earthquake tremors to the oven structure. The "floating slab" would be a better anti-earthquake remedy. Just a thought....

[clofgreen]

Re: Continued Design Ideas

I think his reason was because the oven is top heavy and the slab isn't very wide, only 4-7 by 5-3. He said the slab would have to be quite a bit wider and pretty beefy to counter the force or something like that. But then, I didn't understand half of what he said.

[clofgreen]

Re: Continued Design Ideas

After careful review of all factors and advice, I have decided to go with a slab instead of a foundation. I dug down to original soil and backfilled with fine native sand, compacting every couple of inches. On top of that I have five inches of gravel also compacted. Around this I plan to put drain pipe. There shouldn't be any frost heave on this baby (crossed fingers).

As I prepare to make my pour, I'd like a couple of you veterans to review my plans and let me know if what I'm doing makes sense. I kind of expect that this is structural overkill and if so, I'd like suggestions where I can cut back.

Be aware that I'm using 10 inch CMU because it was free.





I thought it would be helpful to post the conceptual design image for those who haven't been following this thread.




Craig

[ggoose]

Re: Continued Design Ideas

Nice...that thing looks real! I would favor placing the slab rebar in the unsupported areas (the spans), rather than where the cmu's are, as the slab will already be supported there...perhaps just add a few peices across the center span, and make sure they will be in the bottom quarter to third of the slab. Cheap insurance to prevent cracking...

Just my $0.02.

gene

[clofgreen]

Re: Continued Design Ideas

Today was a beautiful day here in Utah and I was happy to spend some of it working on my WFO. But with grandkids visiting I kept getting distracted (but I'm not complaining. They're a lot of fun).

I brought the gravel up to finish level and compacted it good then set the forms which were taken from the deck I cut out.



I picked up 50 ft of rebar from a neighbor who had it sitting in his garage for several years. I cut it with a metal grinder wheel that I picked up at home depot that happened to fit my Makita circular sander. I bent the rebar with an old pipe that's been kicking around my shop looking for a use. It sure came in handy today. My son took my car fishing so I wasn't able to get over to HD to buy the plastic and wire mesh but as soon as I get that I think I'm ready to pour the slab. (BTW, the big chunk of concrete, most of which is buried, was just one of the treasures I found when digging the hole. I also found a conc sidewalk or patio or something a few inches beneath that. They were solid so thought I'd just leave them there.)



Here's that grinder wheel.



I'm not going to get back to this until Tuesday so if there's something anyone sees that I'm doing wrong please let me know. This is my first time doing anything like this.

Craig

[david s]

Re: Continued Design Ideas

I can't see that drill lasting too much longer if you continue to use it as a grinder. Do yourself a favour and get a 4" angle grinder, they are an indispensable tool, you can cut or grind steel, concrete, wood, ceramics etc. using the appropriate discs. Keep your makita drill for drilling.