House extension Wembley work for ordinary HA0 and HA9 houses starts with a Brent planning decision tree — permitted development, prior approval or a full householder application — then a design that matches the stock. The most common ask we see is a rear single-storey kitchen-diner. GSMS Construction Ltd builds rear, side, wrap-around and double-storey extensions on a fixed-price contract after a free survey. Call 07717 790273.
Updated 30 September 2026 by GSMS Construction Ltd, Southgate N14.
- Brent SPD (January 2025) plus national PD depth tests (3 m / 4 m; 6 m / 8 m prior approval) decide the route before drawings leave the office.
- Kitchen-diner use-case: open the back wall on many Sudbury, Preston and Tokyngton semis; side-return fills on tighter HA0 terraces; wrap-around where the plot and 45-degree tests allow.
- Sudbury Court and Wembley High Street conservation areas — with Article 4 — change what is possible under PD.
- Fixed price after survey. 5-year workmanship guarantee. In-house RC frame capability for heavier structural jobs.
5-year
Workmanship
Fixed price
After free survey
HA0–HA9
Brent coverage
10–16 wks
Typical single-storey
VAT
429761270
Book a free house-extension survey in HA0 or HA9.
This is the dedicated house-extension page for Wembley. For RC frame, basements and commercial work see our construction company Wembley page. Combining a loft with the ground-floor work? See loft conversion Wembley. For a published Croydon overview see house extensions Croydon.
Brent SPD and PD decision tree for a house extension in Wembley
For a house extension in Wembley, national permitted development rights for rear work are summarised on the Planning Portal extensions page. Depth, height, eaves and materials limits still apply.
Decision tree we walk on the free survey
- Title and designation. House (not flat)? Outside Brent’s 22 conservation areas and Article 4? Not listed?
- Modest rear PD? Single-storey rear up to 3 m (terrace/semi) or 4 m (detached), within height/eaves tests, matching materials → often PD outside designated land.
- Larger rear? 6 m attached / 8 m detached needs neighbour consultation / prior approval — not available on designated land.
- Side, wrap-around, double-storey? Usually a householder application. Brent’s Residential Extensions and Alterations SPD (January 2025) guides depth, height, 45-degree neighbour tests and street character.
- Paper trail. On a clean PD scheme we still recommend a Lawful Development Certificate. Building Regulations sit on a separate track either way.
Read Brent’s conservation areas pages and the Residential Extensions and Alterations SPD before you assume a route. Where planning is required, expect decision timescales that can stretch toward 8–13 weeks before you break ground.
Kitchen-diner and other extension types for HA0 and HA9
Wembley housing is mixed: 1930s semis, terraces around Wembley Central and Alperton, and regenerated stock near Wembley Park. The right extension follows the plot, not a catalogue — and the kitchen-diner is the use-case most families actually start with.
01
Rear kitchen-diner
Open the back wall on many Sudbury, Preston and Tokyngton semis. Slab, insulated walls, pitched tile or flat GRP with a lantern, bi-folds or sliders to the garden. Modest depths often stay PD outside conservation areas.
02
Side-return / wrap
Reclaim the alley, or combine side and rear into an L when the 45-degree neighbour tests allow it. SPD amenity tests matter most here. Side PD falls away in conservation areas.
03
Double-storey
Kitchen below, bedroom or bathroom above, shared foundations and roof. Usually needs planning. Typical on-site 20–28 weeks, plus 8–13 weeks if planning is required.
Single-storey rear kitchen-diners
Single-storey rear kitchen-diners
The most common ask. Open the back wall, add a concrete slab, insulated cavity walls, and either a pitched tile roof or a flat GRP roof with a lantern. Bi-folds or sliders take you into the garden. Many modest rear schemes stay inside PD outside conservation areas if they meet the 3 m / 4 m depth and height tests.
Side-return and wrap-around builds
Side-return and wrap-around builds
A side-return build reclaims the alley beside many semis and terraces. Wrap-around combines side and rear into an L-shape when the plot and the 45-degree neighbour tests allow it. These are the schemes where Brent’s SPD amenity tests matter most. Side extensions are not permitted development in conservation areas.
Double-storey options in HA0 and HA9
Double-storey options in HA0 and HA9
When you need a larger kitchen below and a bedroom or bathroom above, a double-storey extension shares foundations and roof. It usually needs planning permission. Two-storey rear PD, where it exists at all, is tightly limited and is often the wrong fight on a Wembley semi.
GSMS timescales for a standard single-storey rear extension are typically 10–16 weeks on site; double-storey or structurally complex work can run 20–28 weeks, with planning adding 8–13 weeks where required.
How we quote a Wembley extension
We do not invent a Wembley pound-per-square-metre table for this page. Every quote is fixed after a free survey of structure, drainage, access, neighbours and finishes. Planning, structural-engineer and party-wall fees stay extra unless we wrap them into a managed package.
What moves a Wembley quote (no rates — just factors)
- Drainage — foul and surface connections that satisfy Building Control
- Glazing — bi-folds, sliders, lanterns and how much wall becomes glass
- Storeys — single-storey kitchen-diner vs double-storey with a room above
- SPD amenity — 45-degree lines, neighbour outlook and street character
- Structure — steels or RC where openings and spans demand it
Call 07717 790273 or 07453 292996, Monday to Saturday, 9am–5pm, for the free survey.
Building Regulations and party walls
Every extension is building work. You need Building Regulations approval for foundations, structure, insulation, ventilation, electrics, drainage and fire. We coordinate inspections with Brent Council Building Control. Party wall notices follow the Party Wall etc. Act guidance on GOV.UK where the Act applies.
Structure, thermal, drainage and party wall — tap to open
Structure, thermal, drainage and party wall — tap to open
- Structure. Foundations and steels sized to the span — our in-house RC frame capability matters on the heavier jobs.
- Thermal. Walls, floors and roofs to current Approved Document L.
- Drainage. Surface water and foul connections that satisfy Building Control.
- Party wall. Notices where the Act applies on terraces and semis in HA0/HA9.
How GSMS builds your home extension in Wembley
Your extension stays on one fixed-price contract from the free survey to Building Control sign-off.
Five steps, one crew
01
Free site visit: scope, access, designation, drainage and neighbours.
02
PD, Lawful Development Certificate or householder route confirmed in writing.
03
Fixed-price contract. Structure, roof, windows, electrics and finishes itemised. VAT 429761270.
04
Build from groundworks through second fix. Single-storey 10–16 weeks; double-storey 20–28.
05
Building Control sign-off and a 5-year workmanship guarantee.
GSMS Construction Ltd is registered at Southgate N14 and already publishes Wembley HA9 coverage with HA0 Sudbury and the wider Brent radius. Hours: Monday–Saturday, 9am–5pm.
Areas we cover in Wembley
We build extensions in Wembley Central · Wembley Park · Alperton · Tokyngton · Sudbury · North Wembley · Preston · Barn Hill · Kenton edge · Northwick Park edge.
Postcodes: HA0, HA9 — with wider Brent and North West London coverage on request. See also areas we cover.
This page covers home extensions across HA0–HA9. Borough-wide planning and cost context is in the House Extensions in London guide — use that for research, then book the Wembley survey here. Roof-space projects: loft conversion Wembley.
Related GSMS services nearby
- Loft conversion Wembley — dormer, hip-to-gable and Velux in HA0–HA9
- Construction company Wembley — general building across Brent
- Loft conversion Ealing — 1930s Metroland hip-to-gable lofts
- House extensions in London — London-wide planning and cost context
Frequently asked questions
Many modest single-storey rear extensions on ordinary houses outside conservation areas can be permitted development if they meet national depth and height limits (typically 3 m attached / 4 m detached). Double-storey, wrap-around, side extensions on designated land, flats, listed buildings, and homes in Sudbury Court or Wembley High Street conservation areas usually need a full application. Larger 6 m / 8 m rear depths use the neighbour-consultation route and are not available on designated land.
We give a fixed price after a free survey. We do not publish a pound-per-square-metre table. Structure, drainage, glazing, kitchen fit-out and whether the scheme is single- or double-storey move the figure more than the postcode.
A standard single-storey rear extension typically takes 10–16 weeks on site. Double-storey or structurally complex extensions can take 20–28 weeks. Planning, where required, usually adds 8–13 weeks before you break ground.
It is Brent Council’s January 2025 design guide for householder extensions and alterations. Applications that need planning are judged against it — depth, height, the 45-degree neighbour tests, and how the addition reads from the street. We read it before we draw.
Yes. We sequence structure, scaffold and finishes so the two packages do not fight each other. Start the conversation on this page or the loft conversion Wembley page for your roof type.
Party walls, conservation and choosing single or double storey
Party walls, conservation and choosing single or double storey
Usually yes in HA0 and HA9 where the new wall, foundation or roof sits on or near the shared boundary. We flag this on the free survey and can coordinate notices under the Party Wall etc. Act 1996.
Some rear PD can remain, but side extensions, cladding changes and the 6 m / 8 m larger-home route are typically off the table on designated land. Article 4 on residential conservation streets can remove further rights. We check the map before we promise PD.
Choose single-storey when the need is a kitchen-diner and the garden can spare the depth. Choose double-storey when you also need a bedroom or bathroom above and you are ready for planning. We will not upsell a second storey that the plot or the SPD will not carry.
Drainage connections, glazing area, single vs double storey, kitchen fit-out level, SPD amenity tests (45-degree lines and neighbour outlook), access for groundworks, and whether steel or RC is needed. That is why we survey before we fix a price.
Yes. VAT number 429761270. Quotes say where VAT applies.
Book a free extension survey in Wembley
If you want a house extension Wembley that starts with Brent’s planning route and ends on a fixed-price contract — kitchen-diner, side-return, wrap-around or double-storey — call GSMS Construction Ltd.
Monday–Saturday, 9am–5pm. Free survey. Fixed-price contract. 5-year workmanship guarantee.
Call 07717 790273 07453 292996 Email the survey pack
HA0–HA9. gsmsconstructionltd.co.uk