Finishing tools are shown in figure 11 and they are used as described below. Immediately after compaction, pass the float from the front to the back of the concrete surface to make it smooth and eliminate any irregularities. This operation also brings enough mortar to the surface to facilitate finishing.

However, do not overwork the surface, as this may affect its durability. Use a hand float when working on small surfaces.

Immediately after grading, pass a trowel over all the forms to a depth of approximately 25 mm.

Finishing operations on edges and joints and smoothing of surfaces is only begun once the concrete has started to set and there is no more bleed water on the surface.

Finishing should be started when there is no more free water on the surface and the concrete can support the weight of a foot with an imprint of no more than a few mm.

To start, the edges are first shaped with a small radius edger (12 mm or less). The edger should be passed along the length of all the forms, including the pieces of wood that are to be left as joints. If you are using a groover to make joints by hand, the work should be done at the same time as the edges. The edges and joints should be finished at the same time as the surfaces.



Control joints (fig.1 and fig.2) should have a maximum spacing of 3 m in all directions. It is a good idea to indicate the placement of these joints on the forms before starting the placing, using string lines or straight boards.

The joints are made with a groover once the concrete has started to set, with a concrete saw after it has hardened, or by attaching to the forms 19 mm x 89 mm or 38 mm x 89 mm strips of sequoia or cedar that will remain embedded in the concrete. These strips are held in place by wood stakes that should be removed after grading before the concrete hardens. If you plan to remove these stakes, do not nail the strips to them. However, if you are going to leave the stakes in place, you will have to drive them in or saw them off 50 mm below the surface of the finished concrete.

You can choose to keep the relatively smooth texture produced by the float for the final texture without glazing. An attractive finish can be obtained by making circle arcs with the hand float. This final smoothing operation is done after the concrete has started to harden. Install 125 mm x 600 mm boards over the concrete surface so you can walk around and kneel on it. The finisher makes wide circular movements, moving backwards.

If you prefer a rough texture with no float marks, pass a wet broom over the surface. The concrete must be hard enough for the marks left by the broom to remain there. The texture will be more or less rough depending on how stiff the broom fibres are.

If you want a really smooth surface, use a steel trowel after floating. However, a smooth finish is rarely desirable for outside surfaces such as sidewalks patios. We recommend not using this technique in these cases. The reason for this is that when trying to obtain this smooth finish, there is a tendency to grade and smooth the surface too much, before the concrete has sufficiently hardened. All outside construction is subject to extreme temperatures. Premature or excessive trowelling weakens the surface which will then have a tendency to scale, crack, and produce dust.

Wash your tools in water as soon as you have finished.

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