Sunday, 9 June 2013

Concrete Raised Beds - Second Try

Today we poured the walls of the second 4x4 concrete raised bed, and the floor of the first one.
Ready to pour
Our first attempt proved to have design flaws - the inside walls were very difficult to remove. To remedy the situation, my husband purchased a sheet of treated 3/4" plywood to make the inner walls of the form.  This time they were joined by metal corner pieces and allowances made for walls to slip out easily once the concrete had hardened.  The smooth finish should make them easier to remove.
Pouring the floor
First we poured the walls of the new bed which took a little over 4 wheelbarrow loads of cement with the leftover from a 5th going to the floor.  Then another 2 wheelbarrow loads were poured into the floor of the first bed.  We used a rake to push the cement into place.
Floating the wall top
To finish the tops of the walls, my husband used a yellow cedar float made for him by our friend, Ken, who had come up with the idea of making forms for raised beds.
Floating the floor - note the drainage pipe which will be cut off when the cement has hardened
A larger yellow cedar float was used to finish the floor of the first bed.  Later, when the cement has settled a little, my husband will smooth the floor with a metal finishing float.  The edges of the walls will be shaped with a metal finishing edger.
Finishing tools
We plan on building 4 of these beds and it works really well to pour a wall and a floor at the same time.  And of course, I already have plans for these new beds.  One will be a strawberry bed and another will have winter vegetables.  A third will be a cold frame and I'm thinking this will be achieved by inserting hoops in the bed and covering them with plastic.  This way, a wooden frame won't create any shade for the plants, or provide a structure for wood bugs to hide under.  I can hardly wait!

3 comments:

  1. Did 4" prove to be thick enough? I was considering doing this, but with 6" (to ensure all rebar is covered by at least 3" of concrete)

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    1. 4" was adequate. Our original forms were given to us by a contractor friend who had used them for his own raised beds. Those beds were 4'x13' and needed ties to hold the sides together because of the length. 6" ties had to be cut down for the 4" sides. The only problem we ever experienced with the sides was when we took the forms off too soon and one side cracked. The 4'x4' beds were small enough that they didn't need ties.

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