How To Pour Concrete Wall Footings

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Down And Dirty

The earthbag-wall home I’m building in southeastern Arizona is at the point of needing concrete footings poured for the interior walls. All but the full length, central, east-west bearing wall, that is. That one is already in place, sitting on nothing more than a row of loose concrete bricks. It was dead-center winter when the time came to build that wall, and even this far south (about a mile north of the Mexican border), it was too cold to risk pouring concrete.

We did have one concern. About 60 square feet of soil (the home still has a dirt floor at the moment) got wet, or at least damp, and stayed that way for weeks. While the most likely cause involved heavy rains prior to installation of the French drain system, it was also possible the incoming water main line could have begun leaking. Fortunately, just today it became absolutely clear that the ground is drying out at last. No leak, just not that much airflow to dry the surface. We’re good to go.

The footings only needed to be wide enough to accommodate a 2″ x 4″ sill board on top, so a short chunk of board in that size was simply placed between two cut-to-length pieces to keep the width accurate. Between that and leveling the ground with nothing but a shovel, a level, and a piece of string, however, took more time than anticipated. In all, 14 lengths of 2″ x 4″ needed to be cut, assembled, placed, and secured in place with 12 inch spikes driven into the ground at various points. By the time it was done, pretty close to 14 hours of painstaking labor had been expended–nearly an hour for each board!

Thankfully, the end result was satisfying.

We now have the south half of the home precisely divided into two bedrooms, each with a full bath. On the north side, one half was “moved back” an extra foot to allow an additional 16 square feet in the living room. Then in the northwest “short half”, what had been originally designed as a mere hallway was widened to become a true room with shelving for tools on one side and the other side allotted to a linen closet plus a pantry. Moving those two walls cut down my office size by about 20 percent, but there’s still enough left for comfortable function. Pam gets the credit for those adjustments.

The key "crossroads" where forms come together between the two side-by-side bathrooms.

The key “crossroads” where forms come together between the two side-by-side bathrooms.


One bathroom corner (note the triangular braces to keep things at right angles). The form ends at what will be a bathroom doorway.

One bathroom corner (note the triangular braces to keep things at right angles). The form ends at what will be a bathroom doorway.


The form for the rest of the bathroom wall footing (in my bedroom).

The form for the rest of the bathroom wall footing (in my bedroom).


The form showing the wider space on the left which transformed this area from a simple hallway to the back door into a space to accommodate tools, linens, and groceries. The stack of bricks was needed to hold down a warped board.

The form showing the wider space on the left which transformed this area from a simple hallway to the back door into a space to accommodate tools, linens, and groceries. The stack of bricks was needed to hold down a warped board.

Oh, Yeah, The Mixer

At age 66, I’d never owned a concrete mixer until a few days ago. My Dad had one on the ranch when I was a kid, but as an adult I’d been cementitiously deprived. A mixer will be absolutely necessary for mixing stucco in a few weeks, however…so we had the perfect excuse to go buy one.

The three big building materials stores in town are Home Depot, Lowes, and Sutherland’s. All three stock mixers, but the catch of the day turned out to be at the smallest of those three, i.e. Sutherland’s. It had the only propylene tub (as opposed to steel), which seemed like it ought to clean up fairly easily and which certainly won’t rust.

It came in a box with the cool name of “Black Lynx”.

Putting the machine together was no big deal. The only two momentary head-scratchers in the process were:

1. From the manual, it looked like the leg brace ought to fit one way (inside the front legs) but that turned out to be impossible; it absolutely had to go on the outside.

2. When it came time to mount the half-horsepower motor, the mounting nuts and washers were nowhere to be found. Turned out they were already on the motor itself and simply had to be removed before mounting, then reapplied. The manual was not really clear on that point.

Be that as it may, the fully assembled and power-tested Black Lynx concrete mixer with front-accessible dump handle was resting comfortably in a storage shed well before sundown.

Tomorrow: We mix and pour! Hm. Sounds like a bartender….

Black Lynx in the box.

Black Lynx in the box.


Parts, front view.

Parts, front view.


Parts, rear view.

Parts, rear view.


Motor up close.

Motor up close.


Drum up close.

Drum up close.


Legs brought together via pivot pin.

Legs brought together via pivot pin.


Brace applied.

Brace applied.


If you ever need to know the definition of a "shoulder bolt", here are two examples.

If you ever need to know the definition of a “shoulder bolt”, here are two examples.


Everything but the all-important drum.

Everything but the all-important drum.


Ready to rumble!

Ready to rumble!

Today Is The Day

It seemed like it took forever to actually get everything set up to pour concrete today. Some of the steps:

1. Move the pickup truck containing ten 80-pound bags of concrete premix into position.

2. Wrestle a few of the bags back onto the tailgate into “ready position”.

3. Tools in place–three different shovels (long story), a scoop thingie that wound up not being used, one trowel.

4. Place temporary “plank bridge” over the doorsill to proide an easy-access ramp for the wheelbarrow.

5. Check wheelbarrow clearance with mixer in dump position.

Uh-oh. Either the Black Lynx is a poorly designed model, or our wheelbarrow stands taller than most. The rotating drum will actually come into contact with the wheelbarrow. This is not a good thing. The solution wasn’t difficult. Four 10d nails pulled together a three-inch step. Place the rear wheelbarrow legs onto the step, tipping the barrow forward, and drum clearance is achieved. Time to mix!

Safety note: All concrete “instructions” advise the use of safety goggles, a breathing mask, and gloves when handling the powdered gray stuff. I use none of those. OSHA is, in my opinion, highly overrated. Concrete dust has never bothered either my eyes or my skin, and to avoid (or at least reduce) lung contamination, I do at least check which way the wind is blowing and…take a deep breath and more or less hold it when opening a new bag of premix.

It had been a while since I’d done much with concrete, and very little of what I had done in the past involved finish work. Getting the water-to-cement ratio right isn’t difficult for me, but I’m hardly an ace with a trowel. Fortunately, these wall footings will all be hidden by framing lumber shortly, so strength trumps beauty by a humongous factor.

Whew!

One key pointer: The instructions on the premix bags said to pour the dry cement and then add the water for mixing. Bad idea. That worked okay for the first trial batch. After that, dry mix would jam up in the bottom of the mixer. Water would fail to penetrate the jam. Slow, irritating shovel work would ensue, followed by finishing the mix the hard way–manually–in the wheelbarrow. Switching the sequence so that the water was circling ’round and ’round in the mixer tub first…worked very well. In the end, here’s how it worked:

1. After dumping a load of mixed concrete into the wheelbarrow, pour 2.25 gallons (easily measured by using one gallon jugs for water supply) into the mixer and let it run.

2. Place the wheelbarrow of ready concrete into the forms using a shovel, then smooth things out with a trowel.

3. Get the next batch going by pouring in two bags of premix and…repeat the process.

Worked like a charm. It took all afternoon to fill all the forms, a total of roughly 72 running feet. Pam wants me to leave those forms up for a very long time–she’s afraid the concrete won’t “dry” quickly. Even though it’s a matter of “curing” rather than “drying”, that’s fine. When they do get removed, I’ll take a few last photos of the finished footings.

In the meantime, it’s been another fine day in the neighborhood. The ten bags of premix got the job done with no more than two shovelfuls of concrete to spare. The polypropylene tub cleaned up slick as a whistle with nothing but a bit of water from the garden hose.

And I even improved my game with the trowel…a little.

Ready to get started.

Ready to get started.


Checking clearance. Note low step under rear legs of wheelbarrow.

Checking clearance. Note low step under rear legs of wheelbarrow.


A bag of premix.

A bag of premix.


Mixing.

Mixing.


Shoveling out dry cement stuck in the bottom, a problem solved by pouring the water first.

Shoveling out dry cement stuck in the bottom, a problem solved by pouring the water first.


One form filled.

One form filled.


Making progress.

Making progress.


Definitely not too soupy--note the left half, all piled up, before being smoothed with the trowel to match the right half.

Definitely not too soupy–note the left half, all piled up, before being smoothed with the trowel to match the right half.

The Final Footings

When the forms were removed (two days after pouring), one glaring boo-boo was…um…glaring. Worrying about getting the concrete mix too wet, too “soupy”, had led to producing lots and lots of lousy lower edges in the finished concrete beams. In other words, the mix was too “stiff” to flow easily into every crack and/or crevice. If this concrete work was to remain exposed to view, it would be entirely unacceptable.

Fortunately, that’s not the case. Interior paneling and flooring will eventually cover ever square centimeter of the gray stuff. Nobody will know about my substandard concrete pour except my wife, me, and however many folks view this hub over the years.

I can live with that.

After all, these footings aren’t even for bearing walls. All they need to do is hold the sill boards away from direct contact with the Earth, and they’ll do that job just fine. I’ll do better next time.

Beyond that corner lies Pam's bathroom-to-be....

Beyond that corner lies Pam’s bathroom-to-be….


...and here we have the laundry!

…and here we have the laundry!


Closeup of one footing which shows the rough lower edge where concrete failed to fill the form smoothly and completely.

Closeup of one footing which shows the rough lower edge where concrete failed to fill the form smoothly and completely.

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