Requirements for building over sewers
If you are building or extending a building that is within 3m of the centreline of a public sewer the work must meet with certain standards to protect both the sewerage authorities' asset (the sewer) and the building from any possible damage. In some cases it may be necessary to obtain a formal written consent (Building Over Agreement) from the sewer authority ( United Utilities) before proceeding with any building work.
How can the sewer cause damage to a building
Damage to the building or extension may be caused if:
- foundations are not suitably designed or constructed and this causes settlement of the ground around the sewer pipe; or
- where the sewerage authority need to carry out repairs to the sewer pipe and, in doing so, excavations occur that might undermine the stability of the foundations of the building - causing settlement.
Conditions that require a formal building over agreement from the water authority
In cases where a building or extension is closer than 3m to the centreline of a sewer pipe and the sewer pipe is greater than 225mm in diameter or the depth of the bottom of the sewer pipe is greater than 3m below ground level, then it will be necessary to obtain a Building Over Agreement, from United Utilities before work to construct the building or extension begins.
In such cases the protection measures that the sewer authority stipulate in any Building Over Agreement will be inspected by engineers from the sewer authority.
Conditions where Manchester Building Control can inspect the work and inform United Utilities that your proposal is adequate to satisfy their standards for a building over agreement.
Where a building or extension is within 3m of the centreline of a sewer pipe, and the pipe is less than or equal to 225mm in diameter, or the bottom of the pipe is less than 3m deep below ground level then Manchester Building Control has been given authority from United Utilities to approve the sewer provided the protection measures indicated in the building regulations are followed and the work is inspected by the council's surveyors.
Advantages of the agreement with United Utilities
By working with United Utilities we have reached agreement to avoid their inspectors having to also inspect the drain providing it satisfies building regulations and is within the size/depth limitations referred to above.
Your Building Control Surveyor will be able to advise you further