Table of Contents
- 4About the measurements, Materials you will need and Informative notes
- 5Materials continued and cutting list for the form
- 6The plans - dimensions
- 7The form plans - schematic
- 8Step 1.1 Cutting and assembling the frame pieces of the seat form
- 9Step 1.2 Cutting the plywood, the plastic, and assembling the seat form
- 10Step 1.3 Cutting the form pieces for the legs
- 11Step 1.4 Assembling the forms for the legs
- 12Step 1.5 Aligning and bolting the leg forms to the seat form
- 13Steps 2.1 to 2.3 Cutting, shaping and tying the mesh
- 14Concrete mix information
- 15Steps 3.1 to 3.2 Dry and wet mix
- 16Steps 4.1 to 4.3 Applying the release agent, half filling the seat form and placing the reinforcing
- 17Steps 4.4 to 4.5 Topping up the seat form and attach the leg forms to the seat form
- 18Step 4.6 Topping up the leg forms
- 19Step 4.7 Releasing the leg forms
- 20Step 4.8 Releasing the seat form
- 21Appendage: Easier options
Part 3. Making the concrete
Concrete mix information
This concrete seat will take about three-quarters of the average heavy-duty wheelbarrow full of concrete to make.
For this project we are going to make the concrete mix a little bit wetter than normal and add a slightly larger ratio of cement to the mix than usual. This will allow the concrete to get to every corner of the form without too much of a problem. If there is any ponding i.e. liquid puddles of sorts on top of the mix when finished (mixing), then it is too wet. If that is the case, mix in some more aggregate and cement. Likewise, if the mix is too dry, add water. The ready-to-pour mixture should be a good even, flowing consistency.
Three ingredients make the concrete: aggregate, cement, and water.
Aggregate (in this sense and for this purpose) is a mixture of different size stones ranging from 20mm (¾”) diameter maximum, down to the size of a grain of sand. The smaller stones fill up the cavity created by the bigger stones.
You can make your own aggregate by mixing 3 parts gravel and 2 parts sand.
The mixture to make the concrete seat
A standard household plastic 2 gallon (9 or 10 liter) bucket.
Four and a half buckets of aggregate.
One bucket of cement.
Approximately ⅝ of a bucket of water. This can vary depending on the dryness or dampness of the aggregate.
Start with ½ a bucket and add more if needed.
Note: You can purchase concrete mix in handy bags from most building supply stores. The bags contain the aggregate and the cement already mixed, and only require the addition of water.
It is a more expensive way to go but usually more convenient for a one-off project.