How to Make Concrete Paths and Lay Concrete Floors
Care should be taken in siting a concrete path, or any other structure of concrete, to ensure that it is being laid in the most suitable position. Obviously large slabs of concrete cannot be moved once they have been laid. After deciding the siting of the path, the sides should be marked out. This may be done with pegs and a garden line. A reasonable thickness for a garden path would be 2 in. to 3 in., providing the under surface is firm. If the ground is loose, a layer of earth to the depth of about 2 in. should be excavated, and the excavation filled in with brick rubble, or gravel, which should be firmly rammed into the soil.
With this done the edges of the path may be defined by the use of formwork. This simply consists of pieces of wood which are fixed in position with wooden pegs, as illustrated below. It will be seen from this illustration that the pegs inside the formwork are knocked down well below the surface of the shuttering boards. The boards should be aligned with the cord or line used for making out the site, and the boards should be levelled with a spirit-level. If it is necessary to alter the level of a path, as in a sloping garden, this is best done by inserting steps at intervals rather than sharply sloping the formwork. It is not necessary to completely shutter all the edges of the path at one time.
When the section inside the available formwork has been filled, the formwork may be moved, after the cement has set off, and re-positioned for the work of completing another section of the path. The inside surfaces of the formwork are best coated with lime-wash to prevent the concrete sticking to the boards. In addition to the shuttering having a level run, the formwork should also be level across the site, the path being slightly cambered to the middle to allow rainwater to run off.
With the formwork prepared the concrete should be mixed, and labour will be saved if the mixing bunker is placed as near the site as possible. A good strong mixture for garden paths consists of one part cement to two parts sand and four parts shingle. If ballast is used – ballast is a mixture of sand and shingle — the proportion of the mixture can be one part cement to six parts ballast. Mix only as much concrete as can be laid within 30 minutes of mixing at a time. Immediately after mixing the concrete should be laid between the formwork. This is done with the mixing shovel, and the concrete should be roughly levelled and tamped down within the formwork with a rake.
Each batch of the mixture should be laid and finished before the next batch is knocked up. The surface of the path may be roughly finished or it may be topped up with a smooth mixture of one part cement and three parts sand. In most cases, it will be found best to finish a garden path without a top facing, which may become slippery in icy weather. The path is finished with screeding and floating. The screed is a piece of wood which is slightly hollowed in the middle of its length to form a raised camber in the middle of the path. The screed is used to level the path and the surface of the concrete is gone over twice; the first movement consists of resting the ends of the screed on the formwork at the sides and working along the concrete with a chipping movement; when this is done the screed is again worked over the surface this time with a slight see-sawing movement of the screed, to fill in any pits or small irregularities in the path.
The screeded finish is suitable for most types of garden paths. A better surface may be given by working over a path, as the concrete commences to set off, with. The float is drawn lightly over the surface of the concrete to smooth it and the inexperienced handyman will soon get the feel of the job after a few practice movements of . With the path laid and the surface finished, the concrete should be covered with wet sacks. Newspapers will do if sacks are not available, and these should be left undisturbed for about four days, when the sacks or newspapers (which should be re-dampened throughout the setting period) and the formwork may be removed.
Floors of garden sheds, greenhouses, garages, etc., are laid in the same way, and a note of suitable mixes is given in the table of quantities. In the case of floors for outbuildings, the formwork should be arranged so that the level of the floor, which should not be cambered, runs downwards towards the door. The run need only be very slight; its main purpose is to prevent rain-water entering. The floor should extend 6 in. beyond the sides of the building.