Do this before you start drain set up
Do this before you start drain set up
Before starting any plumbing and sewage work yourself you should find out about any Local Authority rules that relate to your area.
You need to explain your work plan in detail to the authority if you wish to install a new drainage system or alter an existing one, the officials will then go through the plan to check if it is in accordance with the rules. However, you will probably not have to inform the Local Authority for replacement of damaged parts or sections of sewage as permission will have already been granted for the initial fitting.
Surface water is basically water from rain and is handled differently from dark waste water in a modern drainage development. An earlier method was to directly discharge this surface water into the sewage drains, but modern homes use a surface water sewer or watercourse or soakaway to drain or absorb rainwater. In a system combining both functions, the rainwater pipes clear out into the dirty water drains through the gully traps that prevent fetid air from sneaking out of the drains. However with the new drainage systems, the foul and the surface water can be kept apart. It’s absolutely crucial that you keep the dirty water sewage system apart from the one for surface water. You should get advice from the local authority Building Department before you start any work in a situation when you are not sure about the sewage system around your house.
Before starting your work, finalise the routes the waste pipes would take. Sewage pipes must be aligned as straight as possible, with inspection chambers at short intervals. You must avoid making your pipe runs too steep. Using surveyor’s site level you can calculate the fall of a drain over a distance to check the values. By establishing a datum point and using a hose filled with water to establish levels you can calculate the fall from the datum in a situation when do not have one of these measures available.
You will need to see to it that you do not impact on the stability of the house whilst installing your drain trench. You have to make sure that no house foundation is weakened if you are laying a drain pipe running parallel to the building.
When fitting in a new sewage system, you should not dig the trench too long before placing the pipe as the ditch could collapse. The pipes should be laid quickly and the trench back filled after the system has been examined thoroughly and tested as required.
Depending on the depth and soil conditions, the ditch may require support. Avoid risks when working in the trench. If you are not entirely confident of the stability of the trench you should add support. Keep the ditch as narrow as you can but of course make sure that there is enough room to work in the trench including any plan, machinery or tools you require. The base of the trench should be clean and even and free from protruding stones or bricks etc. You may need to import a suitable material for the base of the trench if the existing material is unsuitable.
For pipe support do not use bricks or other hard materials in the trench. This will damage the pipe and must never be used as temporary or permanent support. The bedding should be properly compacted with hollows made to accommodate the joints in the pipes. The support should be smooth and even, from the beginning of the pipe to its end.
When designing your sewage system, it is important to make all parts of the pipework reachable via a set of drain rods should a blockage occur. This need for drain rod access can be easily achieved by keeping the pipeline straight and in short sections. Always make sure that rodding access is allowed in an inspection chamber at any point where the direction of the pipework changes.
DIY plumbing and drainage is certainly within the bounds of most DIY enthusiasts.
