Monday, November 4, 2013

CONCRETE SHOES... ERR, FORMS

With the patio base almost complete, and the slate paving stone on order, it dawned on us that it was time to create the concrete base forms for our two raised garden beds, and the large step we had planned from the deck to the patio. We had been procrastinating on these projects because it meant mixing concrete by hand, which is a slow and back-breaking process. 

Also, this was going to be a project that would end up buried beneath the ground, and by this point we were getting a bit tired of "base work" and were ready to move on to the fun stuff.

But, it had to be done, so we set to work creating concrete forms and concrete footings.



The picture above is a before and after of one of the future garden beds. We wanted about 24" of planting area, which meant it needed to be just under 40" from the house to accommodate the ventilation space behind the bed and a seat along the front (but more about that in my next post).  

Not too much to look at, right?

Either way, here was our process.


The frame in the picture above is for the step down from the raised deck to the patio. We wanted it to be good size, and of course I pushed for a curve instead of a rectangle because it would be harder to make prettier as a finished product. 

We used some doug fir 2x10"s that we had on hand to create the three straight sides of the frame, and some thin plywood that was also kicking around for the curved outside, then secured everything with wooden stakes for support. 

The most important thing when creating a frame like this is to make sure everything is level. I was under the impression that concrete was sort of liquid and therefore self leveling but I was wrong. If you build a wonky frame and fill it with concrete, you will end up with a wonky concrete structure. Luckily, we had already gone to the painstaking process of leveling the base, so this wasn't too tricky to do.

The frames were FAR from works of art, but Ryan assured me that it would be fine. Their only real purpose was to keep the concrete in place as it set up. We cut and placed some rebar in the step, then raised it from the ground with a couple concrete wird Dobies (small blocks with wires on them to keep rebar off the ground, not to be confused with everyones favorite house elf), then it was time to get going with the concrete.


I had never worked with concrete before, and had a couple of DUH moments as we began this project, so don't judge me, but here were my realizations:

1. Concrete is HEAVY. Each of those bags weighed 80 pounds, and they weren't all that large in size. 
2. A bag of concrete doesn't go very far. I don't know why I magically expected the concrete to double in size when we added the water, but it didn't. 
3. As it's one redeeming quality, concrete is cheap! Like under $3 per bag... score.

That being said, my recommendation to anyone doing base work with concrete would be to call around local home improvement stores to find a good deal and free delivery, and have twice as much as you think you are going to need delivered to your house. 

We did not do that. Instead we made no fewer than four trips to Home Depot, and had to shlep it home ourselves. 

Live and learn.


If getting the concrete home was hard, it was nothing compared to the arduous task of mixing it all in a wheel barrow. I'm not gonna lie, Ryan did most of this work. We mixed two bags at a time, following the directions on the package, with a garden hoe as a mixing tool, which we quickly learned was a way more efficient mixing tool than a shovel (which we started with, and quickly abandoned) - it allows you to push and pull the concrete around the barrow, as opposed to scooping and rotating with a shovel.

Ryan got a good system going that seemed to work well for him. He started with both bags in the barrow, then added one gallon of water (about half of the total needed) to begin with in the center. He made a volcano-like crater in the center and started by placing the water in it. Then, he slowly began working the water from the crater to the front of the wheel barrow, mixing the concrete as he went. He quickly learned that expanding the crater slowly and allowing the water to help was much easier than trying to mix the whole wheel barrow at once. The closest thing I can relate to this is kneading dough. Start with your wet ingredients in the center, and incorporate the dry material a little at a time slowly into your mix, working outwards towards the edges. This ensures that you have a uniform consistency throughout. 

We had a rather large bowl (a wheel barrow), so we used a rather large mixing cup, in our case a one gallon beer growler that we picked up at Hop Valley Brewing Company on a recent trip to  Bend (some people buy milk in gallons, we prefer beer), it worked the same way as a mixing cup would, assuring we added the same amount of water to each batch and had consistency batch to batch (seen in the picture below).


Once he had two bags mixed, he'd shovel it in to the form, and I'd work on evening it out.


The picture above was taken after four wheel barrows were mixed (640 pounds of concrete). We layed down a second set of rebar in the concrete at this point, this time perpendicular to the first row, to stabilize it and add some support (you can read more about rebar here if you're interested).  


And here's the step closer to being finished. It took 1000 pounds of concrete to create the step, which is 46" wide, 18-24" deep and 9" high. 


The last step was to smooth the concrete out with a trowel to get a nice, clean finish. I really liked the way the concrete settled together into a clean, smooth surface at the end, so different from the original texture it had in the wheel barrow. The concrete float (which Ryan is using in the picture above) worked like a spatula, smoothing out the concrete the way one would smooth icing on to a cake. Very fun. 

After finishing the deck step, we repeated the process at the future sites of our two raised garden beds. We needed a strong and level foundation for the cinder blocks which would be the walls of the beds. Making sure everything was level was trickier over here, but we got it done. In the third of the four pictures below, you can see how we checked for level as we went. We used a board to float across the semi-solid, soupy surface of the concrete, then place the level on it. 


Just to build the bases of the step and the two garden beds, we used just over 2000 pounds of concrete, which meant 13 wheel barrow mix loads by hand and one mighty sore husband.


But we did it together, side by side, so it wasn't SO bad. And Ryan (or as I had affectionately started calling him by this point, Captain Overkill) has the peace of mind that there is good structural support for our step and beds. They aren't going anywhere. At least not until "the big one" hits.

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