Building regulations drawings in Hillingdon

Foundations, drains and the order of work

Deep foundations affect more than the wall. Drains that run through shrinkable ground need flexible joints and falls that allow for movement. New trenches must avoid the protected root zone, which can mean moving a soakaway or a manhole. We draw the drainage on the plan with connections, falls and cover levels, so the builder does not have to guess on site.

Because a protected tree can restrict how the trenches are dug, we recommend settling the foundation and drainage design before the builder is chosen. Two quotes for the same drawing are comparable. Two quotes for a vague plan are not.

A short note on boundaries: a drain or foundation placed close to a neighbour's tree can affect their property, not only yours. Where that is likely, we say so on the drawing and flag the need for a conversation with the neighbour before digging starts.

Large houses, large extensions

Hillingdon is a borough of houses: 68.9 per cent of households live in one, and 56.6 per cent own their home. Where the plot allows, owners add a long rear extension, a side addition or a detached outbuilding with a bedroom.

Any of these can pass through the usual checks: structure, fire safety, ventilation, energy and drainage. A detached outbuilding used as a bedroom or office sits in a different category, because its distance from the boundary affects fire rules for the wall and roof. We confirm which category your build falls into before drawing, then show the right construction. Where the work needs an engineer, our structural engineering in Hillingdon service coordinates the two.

Energy is the other thing a big house changes. A larger extension has more glazing, more roof and a bigger heated volume, and the energy rules ask for a wall, floor and roof that perform together. We show the insulation in each element, the junctions where cold bridges form and the glazing type, and where a home energy rating is needed, the SAP assessor checks that the whole design passes.

Timings and notices

Building control body must decide a full plans application within 5 weeks, or longer if agreed in writing. On the planning side, Hillingdon decided 1,147 householder applications in its latest year, granted 90.2 per cent and decided 94.3 per cent on time.

After approval, the rule is: Give notice of intention to start; work may start 2 days after the notice. Notify completion within 5 days of completing the work. We list both on the handover sheet, with the commencement rule for an extension, so the approval does not lapse because of a start that never quite counted.

Prices, checking and levy

Building regulations drawings start at £845 with VAT included. A second chartered technologist checks every sheet, and if the examiner raises points we revise at no extra charge.

Hillingdon's levy is a single borough-wide residential rate of £160.43/m² (Residential dwelling houses C3, borough-wide) under its London Borough of Hillingdon CIL Charging Schedule (adopted 10 July 2014), together with the Mayor's scheme at £72.73 per square metre in band 2. A terraced house averages £457,686 here. We flag the levy in the handover pack so it is never a surprise after the build.

Related services and neighbouring boroughs

Sheets for site use are covered in construction drawings in Hillingdon, and the home's energy rating is handled by SAP calculations in Hillingdon. If you need consent first, start at planning drawings in Hillingdon, or read architectural drawings in Hillingdon. Nearby, the service is also described for Hounslow, Harrow and Slough.