Pitch fibre drains: condition and repair options

Material identification

Confirm from records and competent inspection

Inspect closely

Deformation, internal condition and remaining passage

Possible decisions

Specialist preparation, lining or replacement

Key limitation

A liner does not automatically correct the pipe route

Identifying pitch fibre drainage

Pitch fibre is an older drainage material and should not be treated as modern plastic pipe. The survey needs to establish both the material and its condition. If identification is uncertain, the repair assessment should say so.

The important points are whether the pipe still has a usable shape and whether it can be prepared for the proposed repair. Material name, property age or a recurring blockage on its own is not enough to specify a method.

Deformation and restricted access

Deformation and restrictions can stop a camera or cleaning tool from passing through part of the run. Any unseen length remains unassessed and should not be treated as sound simply because no defect was recorded there.

Recorded distances, the extent of deformation and branch positions help define the affected section. The route and fall may also need investigation. Clearing one blockage does not show that the rest of a distorted pipe is sound.

Preparation and lining suitability

Pitch-fibre rehabilitation may need specialist preparation before a lining system can be installed. The method depends on the actual pipe condition and the requirements of the selected liner rather than a single rule for all pitch fibre.

If the pipe cannot be prepared to suit the chosen lining system, or has failed severely, local excavation or replacement may be necessary. The repair specification should record the chosen method and any conditions that would require it to change during the work.

Repair scope and completion evidence

The repair record should identify the length treated, the required finished bore, how connections were dealt with and the completion inspection. Any length that could not be surveyed should remain clearly marked as unassessed.