Mongo's 42" CT Build

[Gulf]

Re: Mongo's 42" CT Build

Monago,
"What they said" .

I see a marked discoloration in the top inch or so of your slab. Is that an acrylic that you applied before or after wrecking the forms?

[mongota]

Re: Mongo's 42" CT Build

Thanks for the kind words.

I have an old Red Lion mixer that I bought years ago, but it's on the fritz. That mixer has a roughly 8" long axle that threads into the back of the mixing barrel. Even with proper greasing, that axle is simply worn out, so there's a bit of wobble in the barrel as it rotates, causing the cogs on the perimeter of the mixing barrel to intermittently miss the gears of the drive motor.

For this oven project, it's all hand-mixing. It moves at a pretty good pace with my wheelbarrow and a masons hoe. I get into a pretty good rhythm when mixing by hand.

The mix that will be a pain will be when forming up the slab going on top of the hearth. It'll probably be a 35 bag pour, with maybe one-fourth of the bags being pigmented for integral slab color. With the top of the slab forms being about 36" above the ground I'll have to transfer the mix from the wheelbarrow to drywall buckets then hand-dump them into the form.

THAT will be a pain. You'll probably see more than one celebratory beer being consumed when that slab is done. lol

[kbartman]

Re: Mongo's 42" CT Build

Great start, you mixing all that concrete by hand just saw a wheelbarrow sitting in the back ground.

Wow !!! Impressive pool setting. The Oven design will definitely complement all. Look forward to following you build.

It's a shame your not a lot closer I have a cement mixer I picked up off of Craig's list that will be going back on the market soon. Surely you didn't hand mix all that Quik-crete If you did, I would not want to get in any tussle with you

Good Luck,

[UtahBeehiver]

Re: Mongo's 42" CT Build

Great start, you mixing all that concrete by hand just saw a wheelbarrow sitting in the back ground.

[mongota]

Re: Mongo's 42" CT Build

The slab. I let it sit until it was pretty well set, then hit it hard with the trowel. It's about as flat as I could have gotten it and I'm happy with the finish. This is after misting it the next day:

[mongota]

Re: Mongo's 42" CT Build

I used 12" blocks for the two courses of mortared CMU that would end up below grade.



With the two courses mortared in, I compacted backfill inside and out, then tied off the rebar.



And yup...more Quikrete...22 bags worth.



Followed by a beverage of my choice:

[mongota]

Re: Mongo's 42" CT Build

Okay...some bad, but in the end, it's all good.

Pulled out the sloped section of pool fence. Dug a hole that seemed to be more full of stone than earth. Oh, how I love Connecticut!



The original plan was to use the earth as the form below grade and just do a perimeter wood form around just the top of the hole to create the finished edges of the slab on grade. Then have a concrete truck delivery come and do a monolithic pour, creating my entire foundation from footing to slab in one shot.

That didn't happen. Concrete guys were apologetic. They've been running hard all summer. Got bumped up to a supervisor, his comment was why send out a truck with two yards when he can send out nine yard loads all day long? They gave me an estimate of two weeks, and admitted that even then it probably won't happen nd I should expect to get slipped.

So...Quikrete is my friend!

Instead of using the earth as my form as I had planned with a truck delivery, I wanted a more precise footing and stem wall volume so I could have an accurate bag count.

So I poured the footings, then formed up the stem walls with old PT lumber I had in a scrap pile. I back-filled around the forms with earth to keep them from bowing, then started mixing bags and placing loads of mix. Final stem wall height is about 20" below grade.

Since I'll be putting two courses of CMU on this, I didn't want a perfectly smooth surface. So it was lightly troweled with a wood trowel to maintain a bit of texture.

[mongota]

Re: Mongo's 42" CT Build

I used graph paper. You used paper with just horizontal lines? That IS old school. lol

Doing some concrete today. Just came in for lunch. I do have a few photos to post. Got to get them uploaded first.

[UtahBeehiver]

Re: Mongo's 42" CT Build

I am old school too, all my plans were on a college rule spiral note book.

[mongota]

Re: Mongo's 42" CT Build

Mongo,

If you have the inclination, Sketchup...

Excellent recommendation regarding Sketchup. I've dabbled with it many times over the years but I just never took the time to learn how to really use it.

I travel for work and don't carry a laptop when I travel. When I'm on the road, that's when I do most of my project planning, which includes the drawing. And the erasing.

I even built my house off of my pencil and graph paper hand-drawn plans.

I'm usually quite late to the show when it comes to using certain forms of technology or software. Heck, I just got a smart phone last month.

[GianniFocaccia]

Re: Mongo's 42" CT Build

I've used my eraser quite a bit, so there's a chance that dimensions in one drawing may not follow through perfectly to the next. It'll all be ironed out in the end

Mongo,

Love your backyard. A WFO will certainly be a nice addition and provide great place to get together.

If you have the inclination, Sketchup provides a free version of their CAD software, which I used extensively in the design of my oven. Its easy to learn and because it keeps all the dimensions accurate automatically, it also forces you to look at design and construction parameters you may not have thought of until they came up - conveniently in the planning stage.

Good luck in your build. Remember to post lots of pics.

John

[mongota]

Re: Mongo's 42" CT Build

Chris, thanks.

Russell, I appreciate the feedback. Multi-day cooking is indeed a goal.

My elbow height is 45-1/2", I can get that with the 44" height as drawn plus I can get an additional inch or so by having the walking surface in front of the oven being lower than the oven's base slab.

The info on the compressive strength of the insulboards will help in my research.

Thanks, Mongo

[UtahBeehiver]

Re: Mongo's 42" CT Build

Quite a post. But you appear to be thinking it out. IMHO here are my answers to you questions:

I have 42" igloo.

1. You can never over insulate but you can under insulate. I have a total of 3.5" of floor insulation. 2" of FoamGlas and 1.5" of ThermoGold 12 Ca Si Board. 4" would not be too extreme especially if you want multiday cooking.
2. Elbow height is a good rule of thumb, you do not want to have to stoop over to load and unload your oven.
3. Same as #1, I have 3" ceramic fiber blanket with 3" of Vcrete. You will have to spend some time fitting the CF blankets to your dome shape since you are not installing v or p crete. Using this helps take the irregular shape out of the blanket. You will only have 1" of stucco avail. for shaping.
4. I used Thermgold 12 which has a compressive strength of .69Kpa, Insblok19 has .3Kpa, and FBs board has .5Kpa. I am sure there are others out there too but I choose one with a higher compressive strength.

Good luck

[mongota]

Re: Mongo's 42" CT Build

It's October and I'm juggling a few other projects. All I really hope to do this year is to get the base structure done. Footings to frost (42" here in CT), 12" wide CMU walls below grade to get to grade, then a slab-on-grade to cover the below-grade work. On top of that slab will go the hearth walls, then a slab to cap the hearth. The mortared stone walls are what will slow me down.

The following spring I'll do the dome.

Now for the oven plans...I drew these up over the past couple of days. I've used my eraser quite a bit, so there's a chance that dimensions in one drawing may not follow through perfectly to the next. It'll all be ironed out in the end. Or cast in concrete?

Here's a rough view of the front of the oven:



The slab-on-grade will be 76" square, with the top edge chamfered. The flat surface of the slab will be roughly 74" square. The corner posts will be set in 1" from the edge. The base structure will be roughly 72" square.

The base will have 10" square cast concrete "corner posts". The front and back of the base will each have a 24" wide door, the doors will be surrounded by a cast concrete arch. Wood will be loaded through the "back door" and taken out of the "front door". That'll prevent me from having to drag wood through a couple of gardens and a couple of gates to load the base with wood.

The walls will be CMU construction covered with a roughly 6" thick veneer of stone. I live in CT. I have no shortage of stone. lol

The slab that the WFO will be built upon will be roughly 80" square and is right now pegged at being 5-1/2" thick, it'll overhang the walls below by about 4". I'd like the slab to have a bullnose edge, probably a covered bullnose.

The oven will be an igloo design, right now I'm planning on covering the igloo with a veneer of stone bout 3" to 4" thick. More on that later. Because I won't have a doghouse full of perlite/vermiculite, I have this drawn with 4" of insulation around the dome oven.

With 4" of board insulation under the oven floor brick, that gives me a cooking height of 44" above grade. I'm 6'4" tall.

Question #1: Is 4" of board insulation overkill?

Question #2: Is a 44" cooking surface too high?

I can maintain the 4" of insulation and lower the cooking surface a bit. Or I can reduce the 4" and reduce the height of the cooking surface. Either/or, or leave it as is.

More foundation detail, this shows the wall structure that makes up the base:



The above should show the 10" square corner posts that are "notched" to receive the corners of the CMU wall. The notching reduces the volume of concrete needed to cast each post to exactly three 80-lb bags. Nothing is perfect in the world of concrete, but I'll take it where I can get it, even if it's just in the design phase.

Combining the thickness of the roughly 6" mortared stone veneer and the 8" CMU wall, the foundation walls will be about 14" thick. That load will be carried through to the footings below grade. Overkill in so many ways. But my igloo will be heavy as planned.

Next, the drawing below shows two separate things combined on one sheet of paper; on the left is a simple detail that shows the CMU wall meeting the corner post. The right side shows the rough scale and detail of the cast concrete corner posts.



And finally, a cutaway of the oven dome structure and how it will sit on the slab:



The dome has a 42" interior diameter. Dome bricks are 4-1/2" thick. Bricks are covered with four 1" layers of blanket insulation. Blanket insulation is covered with a ~1" thick rendering of lath and stucco/mortar. That may end up thicker. We'll see. That 1" thick render layer is covered by a stone veneer roughly 3" to 4" thick.

Question #3: Is four one-inch layers of blanket insulation too much? Diminishing returns? Again, I'll have no vermiculite/perlite. So this will be it.

The drawing shows the edges of the igloo veneer to be a couple of inches away from the edge of the lab. Realize that the slab in the above drawing is actually the 74" square slab-on-grade that the hearth is built upon. The 5-1/2" thick cap slab that the igloo will sit on will is 4" wider in each dimension than what is shown in the drawing. So if built as drawn, the igloo veneer will actually be about 6" from the edge of the slab. I hope that makes sense.

The oven vent size and landing size are guesses at this point. They can be tweaked as needed.

At the bottom of the drawing, what was drawn is a cutaway view of a cast concrete arch that will cover the raw edge of the firebrick arch and stone veneer.

Question #4: Is one type of board insulation stronger than another regarding compressive strength?

I'll have a roof over head. Might be built as a part of the oven. It might be built as an extension of my pergola roof. Either way, the chimney will be properly detailed.

A long post, I know, Probably repetitive, I know. Time to get my wheelbarrow, my pickaxe and my shovel.

Any comments are welcome.

Best to all, Mongo

[hodgey1]

Re: Mongo's 42" CT Build

Nice space, love the pool and patio. Best of luck with your build.