Post-War and 1950s House Extensions in London

Ideas, Costs and Practical Advice for 1950s Homes

After 1945, London had to rebuild fast. War damage, returning servicemen and a baby boom created the worst housing shortage of the century, and the decade that followed produced a very particular kind of home: practical, modest and built to a budget. Today, those post-war semis, terraces and bungalows line the streets of Bromley, Bexley, Harrow, Enfield, Croydon, Sutton and Hillingdon, as well as filling the gaps left by the Blitz in inner London.

They rarely win prizes for their looks, but they often sit on generous plots and have sound, straightforward structures. That combination makes a 1950s house extension one of the best-value ways to create a modern family home in London. Small kitchens, separate dining rooms and narrow halls can be transformed into bright, open spaces, and because most post-war homes have few period features to protect, there is real freedom in the design. A house extension from Simply Extend can turn a dated post-war layout into a home that works for the way families live now.

What Makes a House Post-War?

Post-war housing usually refers to homes built between 1945 and around 1960. In the years immediately after the war, building materials were rationed and private housebuilding was tightly controlled by licences, so most new homes were built by councils. Many were temporary prefabs or permanent houses of “non-traditional” construction, using precast concrete or steel frames instead of brick. By the mid-1950s, controls had eased and private developers returned, building the brick semi-detached houses and bungalows that fill so many outer London suburbs.

A typical 50s house is simple and functional. Expect plain brick or rendered walls, shallow hipped or gabled roofs, large metal or timber casement windows, a small porch canopy and very little decoration. Inside, rooms are compact and ceilings lower than in Victorian or Edwardian homes, usually around 2.4 metres. The kitchen is often a small galley at the back, with a separate dining room, a front living room and sometimes an outside toilet or store that has long since been absorbed into the house.

In London, the most common types are the post-war semi-detached house, the council-built terrace and the 1950s bungalow. Semis and bungalows in particular often come with wide side gardens, driveways and long rear plots, which gives owners plenty of options when they come to extend.

Why Are 1950s Houses So Good to Extend?

The things that make post-war homes feel dated are exactly the things an extension fixes. Kitchens were designed for one person cooking alone, not for families who want to cook, eat, work and relax in the same space. Dining rooms and living rooms were kept separate, and the connection to the garden is often just a single back door. A well-planned extension brings these spaces together and opens the house up to the outdoors.

Plot size is the other big advantage. Many 1950s semis and bungalows were built at lower densities than earlier suburbs, with wider frontages, side access and deep gardens, so there is usually room to extend to the side, the rear or both without losing too much outside space. And because most post-war homes are not in conservation areas and have little ornate detailing, there is often more flexibility in how an extended 1950s house can look, from a seamless brick addition to a bold contemporary design.

What Should You Check Before Extending a Post-War House?

Most privately built 1950s homes are of conventional brick and block construction and are straightforward to extend. But post-war housing includes a wide range of building methods, and a few checks at the start will save problems later.

• Non-traditional construction: Some post-war houses, especially former council homes, were built using precast reinforced concrete (PRC) systems such as Airey, Cornish, Wates, Unity or Reema, or with steel frames. These can be extended, but a structural engineer with experience of non-standard construction should assess the house first, and the extension must not affect any repair certification the property relies on for mortgage purposes.
• Previous extensions: Many post-war homes already have a lean-to kitchen, conservatory or flat-roofed addition from the 1970s or 1980s. These are often poorly insulated and are usually best demolished and replaced as part of the new design.
• Asbestos: Materials containing asbestos were widely used in the 1950s, from soffits and garage roofs to floor tiles and textured ceilings. An asbestos survey should be carried out before any demolition.
• Foundations and soil: Shallow 1950s foundations on London clay may need careful detailing where the extension meets the original house.
• Ceiling heights: Lower ceilings mean the new extension needs thought to avoid feeling squat, and to line up neatly with the existing rooms.

A full house survey at the start of the project identifies these issues early, so they can be designed for and priced properly.

What Are the Best 1950s Semi Detached House Extension Ideas?

The post-war semi is the most common 1950s home in London’s suburbs, and it is also one of the most versatile to extend. The best 1950s semi detached house extension ideas make use of both the side and rear of the plot:

• A single-storey rear extension that replaces the small back kitchen with a large kitchen, dining and family room opening onto the garden.
• A wraparound extension that runs along the side and across the back, creating an L-shaped open-plan space with room for a utility and WC.
• A double storey extension to the side, adding a fourth bedroom or en suite above a larger kitchen or study.
• A garage conversion or rebuild where the original garage is too small for modern cars and better used as living space.
• A front porch extension that adds storage and gives a plain 1950s frontage a more welcoming entrance.
• A garden room or home office for owners who want extra space without changing the house itself.

Post-war semi detached house extension ideas often combine two or more of these. A wraparound downstairs and a side extension upstairs, for example, can transform a three-bedroom semi into a four-bedroom family home with a kitchen to match.

What Are Good Post War Semi Detached House Rear Extension Ideas?

The rear of a post-war semi is usually the easiest place to start. A full-width single-storey extension can add a substantial kitchen and living space, and with a deep 1950s garden, there is often room to go further without overwhelming the plot. Popular post war semi detached house rear extension ideas include:

• Full-width glazing: sliding or bifold doors across the whole rear elevation, so the kitchen and garden feel like one space in summer.
• Roof lanterns and rooflights: essential for bringing light into the middle of the house, where the old back wall used to be.
• Raised or vaulted ceilings: a pitched roof with exposed beams, or a flat roof set slightly higher than the original rooms, counteracts the lower 1950s ceiling heights.
• Broken-plan zones: a kitchen island, built-in seating or a change of floor level to separate cooking, dining and lounging areas without walls.
• Garden-level terraces: where the garden slopes, stepping the extension down creates extra ceiling height and a smoother transition to the patio.

On many semis, the original back wall is load-bearing, so steel beams are needed to open up the existing kitchen and dining room into the new space. This is routine work, and it is where most of the transformation in a 1950s house extension happens.

What Are Good Post War Semi Detached House Side Extension Ideas?

The side of a post-war semi is often taken up by a driveway, a narrow garage or an unused strip of lawn. Bringing that space into the house is one of the most effective ways to add room. Post war semi detached house side extension ideas tend to fall into three groups:

• Single-storey side extensions that house a utility room, boot room, downstairs WC or study, or widen the kitchen. Under permitted development, these can be up to half the width of the original house. Simply Extend’s semi-detached side return extension projects show how much difference this can make.
• Two-storey side extensions that add a bedroom and bathroom upstairs and extra living space below. These need planning permission, and most councils expect the upper floor to be set back from the front and the roof to sit slightly lower than the main ridge, so the extension does not unbalance the pair of semis.
• Garage replacements where an attached 1950s garage is too narrow for a modern car. Rebuilding it as part of a side extension gives far more usable space.

Corner plots, which are common on post-war estates, can offer even more scope. A side extension on a corner plot can sometimes be angled or shaped to follow the boundary, creating a large kitchen and family room without eating into the rear garden.

What Should You Consider for a Post War House Kitchen Extension?

For most owners, the kitchen is the main reason to extend. The original 1950s kitchen was designed as a small, efficient workroom, often barely big enough for two people. A post war house kitchen extension turns it into the heart of the home: a space for cooking, eating, homework and entertaining, with a direct view of the garden.

Good layouts usually place the kitchen where the old dining room or back wall was, with the dining table and seating in the new extension closest to the glazing. An island or peninsula helps zone the space, and enough room should be allowed around it for people to move comfortably. A separate utility room, tucked into a side extension or the old larder, keeps washing machines and clutter out of sight.

Because post-war homes have such plain interiors, there is no need to match period detail. Many owners take the opportunity to bring in mid-century inspired design instead: warm timber, slim-framed glazing, terrazzo or polished concrete floors and simple handleless cabinetry all suit the era while feeling thoroughly modern.

What Are Your Options When Extending a 1950s Bungalow?

The 1950s bungalow is one of the most adaptable homes of the era. Bungalows typically sit on wide plots with gardens on several sides, and their single-storey form means there are options to extend outwards, upwards or both. Extending a 1950s bungalow can follow several routes:

• Rear and side extensions: a single-storey extension to the back or side can add a large kitchen, family room or extra bedroom, often under permitted development.
• Loft conversions and dormers: many 1950s bungalows have usable roof space, and a loft conversion with dormer windows can add bedrooms and a bathroom upstairs.
• Adding a storey: for larger families, removing the roof and building a full first floor turns a bungalow into a house. This needs planning permission and a structural assessment of the existing walls and foundations.
• Remodelling the layout: bungalows often have long internal corridors and small, separate rooms. Combining a rear extension with an internal reconfiguration can create an open living space at the back and keep the bedrooms quietly at the front.

Bungalows also make excellent long-term homes because everything can be on one level. A well-designed extension can add step-free access, wider doorways and a ground-floor bedroom suite, making the house suitable for every stage of life.

Should a 1950s House Extension Match or Contrast With the Original?

There are two broad approaches, and both can work well. A matching extension uses similar brick, roof tiles and window proportions so the addition looks as though it has always been part of the house. This is usually the best option for two-storey side extensions, which are visible from the street and sit alongside a neighbouring semi.

The alternative is to create a clear contrast between old and new. Exact matches for 1950s bricks and tiles are often hard to find, and an extension that is nearly but not quite the same can look awkward. Instead, many owners choose timber cladding, render, zinc or dark aluminium glazing for rear extensions, giving the house a crisp, contemporary character from the garden while the frontage stays much as it was. The mid-century movement that ran alongside post-war housing, with its emphasis on light, glass and indoor-outdoor living, is a rich source of post war house extension ideas.

What Does an Extended 1950s House Look Like Before and After?

The before and after of a post-war house extension can be striking. Before, a typical 1950s semi has a narrow kitchen at the back, a separate dining room with a small window, a tired lean-to and a single door into the garden. After, the same house has a large, light-filled kitchen, dining and family space running across the back, a utility and WC along the side, and wide glazed doors opening onto a terrace.

Often the front of the house barely changes, apart from new windows, a refreshed porch or fresh render. The transformation happens at the back and inside, where the extended 1950s house finally has the space, light and flow that its original layout lacked.

How Much Does a 1950s House Extension Cost?

The cost of a 50s house extension depends on its size and type, the level of finish and how much work is needed on the existing house. A single-storey rear extension will cost less than a wraparound, and a two-storey side extension or an additional storey on a bungalow will cost more again. As a guide, Simply Extend projects in London start from £50,000.

On post-war homes, a few costs are worth planning for specifically. Removing an old lean-to or conservatory, asbestos surveys and removal, structural steelwork to open up the back of the house, and specialist engineering for non-traditional construction can all add to the budget. The kitchen extension cost also depends heavily on the kitchen itself, from cabinetry and worktops to appliances and underfloor heating. Professional fees, planning or Lawful Development Certificate applications, Building Regulations approval and party wall costs should also be included.

Every Simply Extend client receives a transparent, detailed quotation before work begins, so there are no surprises and owners can decide where to invest and where to save.

Do You Need Planning Permission to Extend a Post-War House?

Many single-storey post-war extensions can be built under permitted development. A single-storey rear extension can usually project up to 3 metres from the original rear wall of a semi-detached or terraced house, or 4 metres for a detached house or bungalow, rising to 6 and 8 metres respectively through the prior approval process. A single-storey side extension can generally go ahead if it is no more than 4 metres high and no wider than half the width of the original house.

Two-storey side extensions, wraparound extensions and adding a storey to a bungalow all need full planning permission. It is also worth checking whether permitted development rights have been removed, which is common on some post-war estates, and whether any restrictive covenants apply to former council homes. Few 1950s homes are in conservation areas, but where they are, extra care is needed with materials and anything visible from the street.

Even where planning permission is not needed, a Lawful Development Certificate is strongly recommended. Building Regulations approval will apply to every project, and the Party Wall Act will apply to most work on semis and terraces. Simply Extend’s team checks the planning position for every property and manages the process on the client’s behalf.

How Do You Choose Post War Home Extension Builders?

Postwar house extensions are usually less complex than period projects, but the right builder still makes all the difference. Look for post war home extension builders who can show completed projects on similar homes, who understand the range of construction methods used in the 1940s and 1950s, and who handle design, planning and construction under one roof. A clear, detailed quotation, a dedicated project manager and a proper warranty are all signs of a builder worth trusting.

Why Choose Simply Extend for Your 1950s House Extension?

Simply Extend has extended post-war homes across London, from semis in Bromley and Harrow to bungalows in Sutton and Enfield. Whether it is a rear extension that finally connects the kitchen to the garden, a side extension that turns an unused driveway into a utility and study, or a full wraparound that transforms the ground floor, the team delivers these projects week in, week out.

Every project is handled from first survey to final finish, with in-house design, experienced construction teams and a ten-year guarantee. As part of the Simply Construction Group, Simply Extend can also draw on Simply Architects for more complex designs and Simply Loft for homeowners who want to add a loft conversion at the same time.

Whether you are just starting to explore 1950s semi detached house extension ideas or are ready to move forward, Simply Extend would love to hear from you. Get in touch today to arrange a free consultation, or call us free on 0800 917 7571.

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