Dealing with drains

Noel Larkin answers a readers question published in the Irish Times May 12th 2016

Q My son recently bought an old terraced house. It has a small kitchen extension that was probably exempt from planning permission. On removing the old laminate floor he discovered that the extension was built over an access junction about 10in square which had been concreted over. Is it acceptable to put a double seal cover on the AJ, leaving a tile or floor board from which access can be gained if required. Would a double seal cover eliminate odours?

A It is not unusual during restoration or alteration works to uncover old concealed drainage runs. These may not always still be in use. Old redundant pipes should be removed or capped as they can allow odours to enter the building. In this case, the drain appears to be live and therefore in my opinion, you have two options in order to deal with the matter.

If the drain serves your property only, you do have the option of relocating the drain so that it runs around the perimeter of the extension. This has the advantage of removing the possibility of ingress of odours and also means that access for rodding of the drains would be much less disruptive. It is possible however that the drain also serves neighbouring properties as well as your own. It is therefore likely to operate at a higher capacity and the number of bends on the drain should be kept to a minimum. If this is the case I would not recommend the reconfiguration of the drainage runs.

If you decide to retain the cover at its existing location, the use of a double sealed cover would be satisfactory. These covers are specifically designed to eliminate the ingress of odours and resist back pressure.

In general, these covers can be used with ceramic tiles, rather than with floorboards. Typically, a brass or metal edge detail will be seen, showing the junction location. The fact that the cover remains visible is not to everyone’s taste, but offers a cheaper solution to relocation of the drains.

If you are unsure as to whether the drain is shared or private, a chartered building surveyor working in the locality should be able to advise following a quick inspection.

Noel Larkin is a member of the Society of Chartered Surveyors Ireland

Published in the Irish Times 12th May 2016