Once the foundations and footings are in place on the building plot, and whilst digging machinery is still on site, it may be a prudent time to lay drains.
It may be easier to draw out a diagram of the intended drain works to ensure the correct amount of pipe and fittings are present on site.
It is important to ensure everything is in place and working before backfilling, as solving problems after completion can be difficult and expensive.
Modern houses have two types of drainage, surface water, which deals with rainwater only, and foul water which carries sewage and grey water from showers, washing machines, sinks and W.C.’s.
The trenches will need to be dug to a depth which puts the top of the pipe at least 300mm below the surface level. The best machines for groundworks are at www.hanlon-case.co.uk along with parts, maintenance and servicing.
The necessary gradient is very important to ensure flow. A bed of gravel or pea shingle supports the pipework.
Ideally, to achieve the best flow, pipe should run in a straight line, but this is rarely possible and bends have to be introduced.
It is prudent at this stage to foresee the most accessible places to build in access to the system, rodding points and manhole chambers, for when the building is complete.
The covering lids for the manholes will depend on what is going to travel over them once in place. So the lids can vary from light weight plastic to high tensile steel.
This is also a good time to lay the pipes, ducting and cables of services and utilities. Although not connected by the suppliers, it is easier and much less expensive to lay these at this stage.
Water, gas and electricity pipes are colour coded, and these, along with telephone lines and any other cables can be laid in deep trenches and filled.
The building inspector will have to pass the drain system before backfill can go ahead.
Once this stage has been reached, the house construction can proceed in earnest. Blockwork can be laid if it is to be a masonry type build, or timber frame can be started if this is the type of construction.
Timber frame construction, from this point will appear to be far quicker, but the factory design and build will have been going on for the previous two or three months.
The masonry build will seem much slower by comparison, but once the roof level has been reached, most modern housing is then topped with pre-engineered roofing trusses and completed in days.