Extensions · 51 photographs

Anatomy of a rear extension

One job, photographed from the first cut in the lawn to the ochre feature wall — every stage of a full-width rear extension on a 1930s pebbledashed semi.

The rear elevation, finished

The story

Most builders show you the last photograph. This is the whole story of one extension — the same house, from the day the digger arrived to the day the family got their kitchen-diner — because the stages nobody photographs are the ones that decide whether an extension is still perfect in twenty years.

The house is the commonest type in outer London: a 1930s semi with a decent garden and a rear elevation asking to be opened up. What follows is exactly what we would do at yours.

Breaking ground

The dig is where an extension is won. These footings were cut clean into London clay to the depth the structural engineer specified — not the depth that was convenient — and building control inspected the open trench before a drop of concrete went in.

Spoil went out by grab lorry the same week. On a suburban street, how fast you clear muck decides how long the neighbours stay friendly.

Rear garden of a 1930s semi-detached house before extension works begin — Day one — the rear garden

Mini digger and breaker excavating footings at the rear of the house — Breaking ground

Excavated foundation trench in London clay awaiting inspection and concrete — Footing trench, cut clean

Grab lorry removing excavation spoil from the front of the house — Muck away

Operative compacting hardcore sub-base with a plate compactor — Compacting the sub-base

Steel and blockwork

One steel beam carries the back of the house where the old rear wall used to be. It was sized on calculation, craned in by hand the old way, and inspected on its padstones before anything covered it.

Then the cavity walls came up in blockwork — insulated, tied, and levelled off ready for the roof. Two bricklayers, a line, and no shortcuts you would ever see from the kitchen.

Operative positioning a red-oxide steel beam over the new opening — The steel goes in

Two bricklayers building blockwork cavity walls off the new footings — Cavity walls rising

Bricklayers raising blockwork walls with materials staged on a board — Blockwork off the line

Operative laying blocks on the boundary wall with paving stacked nearby — Working the perimeter

A roof built like a tank

This is a warm roof: thick insulation over the deck, OSB over that, and a single seamless skin of GRP fibreglass laminated on top. No felt, no joints, no places for water to think about.

Two lantern openings were trimmed into the deck and their upstands laminated by hand. The grey membrane you can see cured into one continuous surface — then the lanterns dropped on and the room below got its sky.

Insulation boards laid over the flat roof deck before boarding — Warm roof build-up

Operative fixing OSB deck over insulation on the new flat roof — Decking the roof

GRP matting being rolled onto the flat roof deck — Fibreglass matting down

Rooflight upstand opening framed in the new flat roof deck — Lantern opening trimmed

GRP resin being applied around the roof lantern upstands — Upstands sealed

Operative laminating the GRP upstand for a roof lantern — Detail at the kerb

Cured grey GRP fibreglass flat roof surface — The finished membrane

Aluminium roof lantern installed on its upstand, seen from the roof — First lantern in

Roof lantern glazing against a blue sky — Sky through the lantern

Roof lantern seen from inside the plastered extension — Lantern from inside

The floor nobody sees

Under the finished floor there are five layers, and each one exists for a reason: compacted sub-base, blinding, damp-proof membrane lapped up the walls, a pumped concrete slab, then insulation with underfloor heating clipped over it in tight red circuits.

Every loop was pressure-tested and left under pressure while the screed went down — so if a pipe had been nicked, it would have shouted before the floor was buried, not after.

Compacted sand blinding across the extension footprint — Sand blinding, levelled

DPM laid across the new floor area ready for concrete — Damp-proof membrane

Damp-proof membrane dressed up the walls before the slab pour — Membrane lapped and taped

Concrete being pumped over the membrane for the ground floor slab — Pumping the slab

Red underfloor heating pipe clipped in circuits over insulation — Underfloor heating, zone one

Operatives laying and clipping underfloor heating loops — Circuits pressure-tested

Completed underfloor heating circuits ready for screed — Every loop back to the manifold

Freshly laid screed with levels and straight edge on the floor — Screed struck level

Matching the house

An extension should look like the house grew, not like something parked against it. The render here is pebbledash, matched to the original — the same aggregate, thrown the same way — and the windows sit in the same white as the rest of the elevation.

Inside, first fix, boarding and a full skim. Then the part that makes the room: large-format polished porcelain, laid with levelling clips so every edge kisses the next one flat.

Operatives installing windows in the rendered rear extension — Render to match

New pebbledash render on the extension flank wall — Pebbledash, matched to the house

Stud partition and chop saw during first fix inside the extension — First fix carpentry

Plasterer working on fresh boarded walls inside the extension — Boarding and skim

Skimmed extension interior drying out before decoration — Ready for finishes

Plastered open-plan extension interior with French doors to the garden — Open plan, first light

Large-format floor tiles being laid with levelling clips — Large-format porcelain

Polished porcelain floor tiles with levelling clips mid-installation — Tiling across the slab

The room they wanted

A white shaker kitchen with a black range and gloss metro tiles on one side; a deep ochre feature wall on the other; French doors and coach lamps onto a new patio with rendered garden walls.

That ochre wall was the client's call, and it makes the room. Our job was everything that lets a wall like that be the only thing you notice.

White shaker kitchen units being fitted with black metro splashback — Kitchen going in

Black range cooker positioned during kitchen installation — The range cooker lands

Kitchen sink run and units during second fix — Second fix underway

White kitchen with black metro tile splashback and range cooker — Metro tiles, gloss black

Black chimney hood over range cooker in the finished kitchen — Extraction over the range

Completed kitchen run with black worktops and white cabinets — The working wall

Open-plan room with deep ochre feature wall and polished porcelain floor — Ochre feature wall

Polished floor tiles reflecting light from the garden doors — Light off the porcelain

Black granite worktop against the ochre wall in the finished space — Worktop, lit

Finished open-plan kitchen-diner with ochre wall and French doors — The room they wanted

Completed extension rear elevation with double French doors — French doors to the garden

Finished extension with French doors and exterior lighting — Coach lamps either side

Completed rendered rear extension with French doors and new patio — The rear elevation, finished

New patio and rendered garden walls behind the finished extension — Patio and boundary walls

Finished extension with patio, lamps and rendered walls — Garden handed back

Rear garden with painted wall before landscaping works — The garden it replaced

How every job of ours runs

It starts with a survey, not a phone estimate — then a fixed, itemised written scope before any deposit is discussed. Skips, scaffolding, licences, making good and waste removal are named in it rather than discovered later.

On site you get a named project manager and online progress tracking with photographs like the ones above. You pay in arrears of work completed, and where the work is notifiable, building control inspects at stages and issues the completion certificate — the paperwork a buyer's solicitor asks for years later.

Service: Extensions
Photographs: 51
Payment: In arrears

Answers

Common questions about work like this

Do I need planning permission for extensions in London?

It depends on the property type and what is proposed. Many single-storey rear extensions and loft conversions fall under permitted development, but those rights do not apply to flats and are restricted in conservation areas or where an Article 4 direction applies. We check the planning position for your specific address before quoting, and tell you in writing which route applies.

How do you price the work?

From a site survey, written up as a fixed and itemised scope before any deposit is discussed. If something genuinely unforeseen appears once work is opened up, it is priced and agreed in writing before we continue — never added to the final invoice after the fact.

When do I pay?

In arrears of work completed. You pay for work that has been done and inspected, not for work that has been promised. This has been how the company operates since 2008.

Do you handle Party Wall notices?

Yes, where the work requires them. Under the Party Wall etc. Act 1996, notifiable work on a shared wall needs 2 months written notice to the adjoining owner, while excavation near a neighbouring structure and building at the line of junction need 1 month. We serve the notices and manage the award process as part of the job.

Will I get certificates at the end?

Yes. Electrical work is tested and certificated under Part P, and building control issues a completion certificate where an application was required. You receive the handover pack — it is what a buyer's solicitor will ask for when you eventually sell.

How long will it take?

It depends entirely on scope, and we give a programme with the written quote rather than a guess on the phone. What we will not do is start a job we cannot resource, which is the usual reason a build stalls halfway through.

Other projects

Boutique fit-out, retailRefurbishments A loft conversion, start to finishLoft Conversions Extension and loft together, North FinchleyExtensions A whole-house refurbishmentRefurbishments Bathrooms we have builtTiling Kitchens we have fittedCarpentry

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