36" in Seattle

[vintagemx0]

Re: 36" in Seattle

We wanted our vertical rebar to be set into the slab. 'Not sure if this was necassary, but we mapped-out where the rebar should go with string when we poured and screeded our slab. I marked the tops of the form to indicate where to place a screw, and after the screeding, we put sheet-rock screws into the forms and then loomed string from screw to screw in a fashion that created a pre-planned grid of intersecting strings over the top of the concrete. The intersections of the strings over the wet cement indicated where to place the rebar. I just stuck them (easily) into the concrete by hand.

Granted, the concrete was only 4" thick, but was effortless. I think you could insert them with no more help than a hammer for the last little bit. If you worry about the media deflecting the rebar, grinding a point on the end of the rebar would help. I think it would be pretty easy to insert them. Try it with one and see how it goes.

Ken

[papavino]

Re: 36" in Seattle

I filled my cores with concrete, then pushed the rebar down into them. I made sure they were all the way down by pounding on them with a hammer. It's not that hard.

In terms of the stand being out of level, I agree with Ken. You should be able to correct for this with the hearth pour. Just double check all of your forms to make sure they are level with each other and move on.

[kebwi]

Re: 36" in Seattle

Thanks. It seems apparent that I bit off more than I could chew for my foundation since it was the first concrete job I had ever done in my life (not so much as a post-hole). My foundation presented several complications which a novice probably shouldn't contend with:

• No experience with gauging the proper water mixture (well, this is one is unavoidable you're first time I suppose).
• A nonrectangular shape with several pieces of form around the edge, all of which must be perfectly level and must stay sturdy while pouring.
• Placement against a corner wall, thus preventing external access from two sides.

I would have have more success if I had either: kept it simple (rectangular and away from the wall), or, enlisted the assistance of someone who had solid experience with such a project (not that anyone immediately comes to mind).

Oh well, life goes on. No big deal.

Thanks for all the input. I hope to have the cores poured this weekend.

Cheers!

[kebwi]

Re: 36" in Seattle

Rebared the hearth and fill the cores today. Phew!

Photos:

• Lintel detail, notice the J-hooks at the bottom.
• Vertical rebar per core, J-hook at bottom, L-hook at top.
• "Weak" corner detail (there will be a little more rebar before it's done).
• Full hearth rebar (except a few pieces, see later photos).
• Gravity assist from the retaining wall.

Photos continued in next post.

[kebwi]

Re: 36" in Seattle

Previous post continued.

This photos show the core-pouring job after completion, with a little additional rebar, namely a single very long corner halfway around the structure across both openings and an additional vertical rebar in the "weak" corner.

[ThisOldGarageNJ]

Re: 36" in Seattle

Hey Keb,,
I think it looks great.. Dont worry about the small stuff it all works out..

How are you eventually covering the blocks ? I used the Quikrete Surface Bonding Cement, ( i know I push this stuff alot,No I dont get a commision() Great stuff, very beginner friendly and adds structural strength to your block base.. You can do both the inside and outside with it,, You can also add Acrylic Fortifier for water proofing and color as well...

you cant see it to well in the pic, But I used a grout sponge for a slightly rough finish, or you can trowel it smooth...

Keep up the good work your doing fine, Your re-bar looks great..and practical
Cheers
Mark

[kebwi]

Re: 36" in Seattle

ThisOldGarageNJ:

You're asking specifically about the concrete blocks, not the dome? My first preference would be ledgestone, which I've seen on some perimeter walls and house sidings around town and which I absolutely love. I suspect I may rule it out once I start pricing it though. Sigh.

I had been shooting to stucco (or the Quikrete alternative) the dome, just not necessarily the storage area. I figured, consistency probably didn't matter since the hearth around the dome won't be horizontal stucco anyway. I'm would like to flagstone the foundation where people stand in front of the oven and am therefore considering flagstone for the hearth as well.

...but I am very interested in the Quikrete for the stucco dome. I've read about it on FB before.

...lastly, I am considering some non-stucco options for the dome, some pretty off the wall stuff that I won't disclose here yet bearing in mind that I really dislike rectangular "buildings" with conventional gabled roofs.

Cheers!

[fxpose]

Re: 36" in Seattle

Looking good so far!

I heard good things about the QuikWall SBC too. More expensive than regular stucco, it is supposed to add additional structural strength, especially on mortarless block walls and such. I intend to use this on my oven build as well as on my current concrete wall/patio job. Orchard Supply Hardware sells them for $18. I've seen them at Lowe's for like $23.

[ThisOldGarageNJ]

Re: 36" in Seattle

I got mine at lowes,,, I think i paid 19 at the time.. If you can Ice a cake you can use this stuff... It has fiberglass strands in it, and they claim its much stronger than a mortar type joint wall.. Though the way Ive seen most of us here (over) build our ovens, I just hope Im not cooking a pizza if they ever drop a bomb, cause thats where Im gonna hide...
Cheers Mark

[Dino_Pizza]

Re: 36" in Seattle

Great job Kebwi on the oven base. It will be soooo much easier to frame your upper slab pour with 2x8's and take your time leveling that to make up for any not-so-level points along your base. It's your last chance to things level but it's easy since you're working at waist height and not on the ground .

What's your plans for supporting the upper slab pour? Will you put plywood under your rebar cage with supports and remove it all after it's cured a week or will you use durock under your upper slab and just leave it in? -Cheers, Dino

[kebwi]

Re: 36" in Seattle

Yeah, I already have the interior filled with plywood precariously balanced on a bunch of loose 2x4s. I'm going to screw the whole assembly together with frame anchors (L-shaped metal brackets) tonight, frame up the exterior with 2x8s tomorrow, and if all goes well, pour the hearth Saturday.

One of the hardest things to find is cheap wooden handles for making my own wood concrete float. I don't want to *pay* for a plank with a stupid handle on it.

I went back and forth on whether to protrude a curved lip over the front entry way (the short axis). If I want to do that, I suppose I need to put in a new piece of rebar hanging over the corresponding area. I dunno, probably not worth the trouble. I would prefer to avoid a perfectly rectangular shape, but whatever.

[kebwi]

Re: 36" in Seattle

Spent the last week building the frame for the hearth slab. There will be a final layer of plastic over the plywood, just to prevent the concrete and the plywood from sticking.

[kebwi]

Re: 36" in Seattle

Poured the hearth slab today. Phew! This is my third batch of concrete for this job (including filling the cores) and I still think it's too dry. I've mixed it wetter each time -- this time to the point where a fistful grabbed from the mixer was downright muddy -- and I'll be damned if I just can't get it to look wet after dumping and distributing it. After screeding, I pounded it down with a 4x6 (no kidding) end on, which reduced the height of the entire slab by a quarter inch. I didn't bother to add more concrete after that, so it came out slightly thinner than intended. Then, no "sweating": no water came to the surface. I eventually misted the surface to get enough water to actually use the float, which was only a partial success. In the end I still didn't achieve that really smooth look of concrete in which all the aggregate has sunken below the surface. I have no idea what I'm doing wrong...and I don't care anymore. I'm sick of how difficult smooth concrete has turned out to be. I thought it would be relatively straight-forward.

I'll probably flagstone the hearth at some point anyway, so in all honesty, it really doesn't matter.

Now, I desperately need to build a stand for my tile-saw. That's the next subproject.

Cheers!

[kebwi]

Re: 36" in Seattle

Oh, just as a follow-up, I really wish my wife had taken photos of me working the concrete mixer up onto that retaining wall. I did it single-handedly by placing 2x6 planks the entire way, including a ramp. It would have made a hilarious time-lapse video.

[fxpose]

Re: 36" in Seattle

Judging from that one photo of the pour the concrete looks a bit on the dry side, but I wouldn't worry about it. It should set up fine.

I have the habit of mixing concrete a bit on the wet side. I've had people tell me my mixes look too slushy and I used to get a lot of water floating to the top. But on my last few concrete mixes I think I've got them just right, adding either more water or more concrete to the mix while mixing to reach that just right slushiness.