Flat Conversion Drawings in Harefield UB9
Fixed-fee, MCIAT-chartered flat conversion drawings for Harefield (UB9) homeowners — London Borough of Hillingdon validation and local constraints handled from the start.
Harefield (UB9) is one of Hillingdon's most rural neighbourhoods — a historic village core wrapped in Green Belt on the northern edge of the borough — and that setting, rather than a standard suburban street pattern, drives how extensions are assessed here. Schemes that keep additions subordinate and in-keeping with the village grain are the ones that move smoothly through the council.
The Harefield Village conservation area protects the scattered building layout, the green and the countryside views, so rooflines, materials and the openness between buildings are treated as part of the heritage. We check both the conservation-area boundary and the surrounding Green Belt designation before advising on what a UB9 plot can realistically support.
Planning in Harefield (UB9): what to know before you apply
UB9 combines two of the strongest planning controls in the borough — a rural conservation area and widespread Green Belt — so extension scale and siting matter more here than almost anywhere else in Hillingdon. We design Harefield schemes to read as modest, subordinate additions that respect the village setting, which is what the council looks for.
Typical Harefield housing stock
A dispersed village centre of cottages and period houses around the green and St Mary's Church, mixing medieval and post-medieval buildings with Victorian and 20th-century infill, set against open countryside on the borough's northern edge.
Streets we regularly draw for in Harefield
High Street · Church Hill · Park Lane · Rickmansworth Road
Flat Conversion Drawings for Harefield (UB9) homes: the package and the process
Every flat conversion drawings we prepare for an Harefield property is drawn to London Borough of Hillingdon’s validation standards and tuned to the UB9 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.
Converting a house into flats is one of the few residential projects in London that always needs planning permission, whatever the size of the property or the number of units created. Splitting a single dwelling into two or more self-contained homes is treated as development regardless of whether any external work is proposed, because the change affects how the building is used and how many households occupy it.
DrawingsDirect draws house-to-flats conversions from the first survey through to a submission-ready planning and building-regulations package. Sound insulation between units, separate escape routes, individual services and London's minimum space standards are designed in from the layout stage, not retrofitted once the council asks for them — which is a large part of why our schemes are approved first time.
Do I need planning permission to convert a house into flats?
Yes, always. Converting a single dwelling into two or more self-contained flats is a change from one home to several, and that subdivision is treated as development requiring a full planning application — there is no permitted development route that allows it, regardless of the property's size or whether the exterior changes at all. The application has to demonstrate that each flat meets space, layout, amenity and parking standards in its own right, not just that the building as a whole is being used sensibly.
Boroughs also weigh the loss of a family-sized house against their local housing policy, since converting a larger house into several flats reduces the stock of homes suited to families even as it adds smaller units. We take that policy context into account when advising on layout and unit numbers, rather than simply maximising the number of flats the floor area could technically support.
What sound insulation is required between flats?
Part E of the building regulations sets minimum sound insulation standards for the walls and floors separating flats, covering both airborne and impact sound. Where an existing house is subdivided, the drawings specify how the party floors and walls between units will be upgraded — additional layers, resilient bars, or a floating floor — and pre-completion sound testing is normally required before the flats can be signed off. Getting this detail right on the drawings from the outset matters, because retrofitting sound insulation after a failed test usually means taking up a finished floor or ceiling that has already been decorated.
| Conversion | Typical scope | Route | Fee from |
|---|---|---|---|
| House to two self-contained flats | Vertical split, separate or shared entrance | Full planning plus building regulations | £1,600 |
| House to three or more flats | Multiple units, fire strategy required | Full planning plus building regs plus structural | £2,400 |
| Flat conversion with a side or rear extension | Additional floor area added to create compliant units | Full planning plus structural calculations | £2,800 |
Flat Conversion Drawings in Harefield UB9 — FAQs
Do I need planning permission to convert a house into flats?+
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What sound insulation is required between flats?+
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Do I need planning permission for a loft conversion in Hillingdon?+
How does the Colne Valley green belt affect my Hillingdon project?+
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