House Extensions Oakwood

Long rear gardens are why people extend in Oakwood, and the trees around them are why the foundations need thinking about first. GS Renovation builds rear, side and wrap around extensions throughout N14, handling groundworks, steel, roof and fit out as one job, with Enfield Council building control inspecting each stage as the work proceeds.

In Oakwood, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Oakwood: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Depth, height and the wide N14 plot

On these plots the constraint is rarely space. Under permitted development a single storey rear extension is limited to three metres on a semi and four on a detached house, with up to eight metres possible on a detached house through the larger home extension route, which needs prior approval from Enfield Council and a neighbour consultation before you build. Side extensions are treated less generously, particularly where filling the gap between two houses would close up the rhythm of a street laid out with space between every pair.

Double storey work brings the daylight rules on neighbouring windows into play and almost always needs a full application. We look hard at what the house has already had done to it, because a 1970s rear addition eats into the allowance and previous owners rarely leave the paperwork behind. Where a plot backs onto the open land north of Oakwood Park, designations can apply that change the policy position entirely, so we check the address against Enfield's mapping rather than assuming a street is all the same.

Housing in Oakwood

Count the homes in Oakwood and you get about 3,450: 52% built since 1945, 44% between the wars and 3% before 1919, with flats at 44% and houses at 56%. A rear extension on a semi in Oakwood digs beside the attached neighbour, so one party wall notice is usual, and 37% of homes here are semi-detached.

Checking Oakwood designations and the levy before drawing an extension

Before an extension is drawn, check the address against Enfield's conservation areas, because they change what can be built without an application. Planning Data records the Trent Park Conservation Area, designated in 1973, as covered by the Enfield Borough Conservation Areas Article 4(2) Direction 2006. Inside any conservation area, a side extension, a rear extension of more than one storey, a roof extension and external cladding fall outside householder permitted development. A single storey rear extension keeps its rights unless a direction withdraws them. Look the Oakwood address up on the Planning Data map and on Enfield's own map, and read any direction that applies, before paying for drawings that assume a freedom the plot does not have.

The Mayoral levy is the other thing to settle early. Under the MCIL2 charging schedule, Enfield is in Band 2 alongside Barnet, Brent, Bromley and Ealing. A modest householder extension sits under the minor development exemption, and a larger one can be exempt too, but that exemption has to be claimed and acknowledged before work starts on site. Starting first can forfeit it. An Oakwood extension that creates a separate dwelling is different, because a new home is liable whatever its size unless a relief is claimed first. We check the paperwork is in place before the first trench is dug.

Foundations, clay and the trees behind Oakwood Park

This is where extension budgets move. Oakwood is on shrinkable London Clay, and where a mature tree stands within influencing distance the foundation goes deeper, sometimes considerably deeper than an optimistic quotation assumed. Depth is worked out from the species, its mature height and its distance from the trench, so on a garden with an old oak or a line of poplars near the boundary a two and a half or three metre trench fill footing is not unusual, with compressible board to the sides where heave is a risk.

That is a cost worth knowing at quotation stage rather than discovering when the digger stops. We put in trial holes before pricing groundworks wherever a tree is anywhere near the footprint. Drainage matters just as much: plenty of these houses connect into a shared run, and where an extension crosses what is now a public sewer you need a build over agreement from Thames Water, which takes time to obtain. We apply for that early, so it is never the thing holding up the slab.

Kitchen extensions in Oakwood

77% of the houses in Oakwood are semi-detached or detached, which usually leaves room for a kitchen extension across the full rear width, with a steel beam over the opening into the house. The fit-out is priced on its own page, kitchen renovation in Oakwood; the build figures are in the table above.

Side return extensions in Oakwood

Side returns belong to Victorian and Edwardian terraces, and only 3% of homes in Oakwood predate 1919, so they are the exception here; most extensions run across the full rear width instead. Our side return extension page covers the build in detail, with build rates of £2,400 to £3,200 per m².

Double storey extensions in Oakwood

Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Oakwood often needs planning permission from Enfield Council. With 43% of homes here semi-detached or detached, the side of the house is often an option too. Planning Data gives the Trent Park conservation area in Enfield a designation date of 1973 (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• Foundations, groundworks and steel frames
• Flat and pitched roofs with rooflights or lanterns
• Side-return and rear extensions

VOA Council Tax stock of properties, March 2025, for Oakwood Park & Highlands. Counts rounded by the VOA.

Before committing to house extensions in Oakwood, it is worth looking at RSJ and steel beam installation in Oakwood, house extensions across Enfield, basement extensions, party walls and extensions, our London house extensions page and Getting Planning Permission.

The GS Renovation Difference in Oakwood

One team from the trial hole to the last coat of paint. We advise honestly on whether you are within permitted development or need a planning application to Enfield Council, price the groundworks from what the ground actually shows rather than a guess, and keep building control inspections and any Thames Water build over agreement moving in parallel with the build instead of behind it.

• Weathertight shell reached before the fit-out begins
• One point of contact on the phone, not a call centre
• Brick and mortar matched to the existing elevation

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.