What gets checked during building control inspections

What gets checked during building control inspections. By now we know that most types of home extension will be subject to building control, and that there are different types of building control applications. What the Inspector specifically checks will depend on the type of extension under construction, but here, according to Merton Council.

Commencement. This meeting kicks-off the build phase of the project. In it, you will discuss the implementation plan ahead and is particularly salient if you did not opt for a full plan application, where potential risks would have been surfaced early doors.

Foundations. Ground conditions and excavations are checked for load-bearing suitability prior to being filled. Proximity to trees, drains, excavation depth and width are key considerations.

Oversite. Before the floor concrete can be poured, the suitability of the substrate beneath it must first be validated, which includes checking the appropriateness of the hardcore used, damp-proofing and floor insulation.

Damp proofing. Any damp-proof courses, membranes and methane layers physically eyeballed for compliance before progressing with brickwork and/or concreting.


Drainage. This is to ensure the drains have been properly laid, and will look or appropriate sizing, material type, fall and line, bed and border material and correct rodding points for maintenance. The drains will also be tested at (a later stage) as part of this inspection.


Structural beams and openings. The beam openings, footings, size and connection will be carefully examined for physical adequacy and cross-checked against the structural calculations previously supplied. Works will only commence to the next inspection milestone once this has been satisfied.


Roof structure & floor joists. Timber work that goes to making the floors and roofs is inspected for adequacy. Amongst the inspected aspects are timber size and grade, structural member centres, bracing, restraints, strapping and noggins.


Thermal insulation. At this stage of works, the shell and core will be up and internal partition framework constructed. Before the new surfaces can be covered up, the Building Control Inspector will check to ensure that the adequate level and type of thermal insulation has been fitted.


Fire proofing. Measures to safeguard against fires are assessed both in the newly extended area, as well as the rest of the house, to ensure a continuous safe means of escape for inhabitants in the event of an emergency. Measures can be wide-ranging depending on the project, though you can expect glazing, staircase, smoke alarms, suitable use of non-combustible materials and escape routes to be looked at closely.


Completion. This final inspection verifies that the newly extended dwelling meets the various regulations and is fit for habitation.


Building control inspections are not designed to regulate the quality of workmanship. Instead they serve a critical function in ensuring that works proceed sequentially and in line with the minimum regulatory standards required. This general list of what gets checked during building control inspections also serves as a convenient project milestone guide to which scheduled stage payments can be hitched.


If you would like some free planning advice, get in touch with us.