Typology Study: Mid-Century Semi

A typical pair of mid-century semi-detached houses

Family semi-detached houses, built in the mid 20th Century, remain sought after as family homes. They are typically located in suburban areas, close to schools and local amenities. Often, they sit on large plots, meaning there is flexibility to expand and adapt the home. This article gives an overview of the characteristics of a typical 1930’s semi and suggests a number of ways these properties can potentially be improved, both to increase space and to bring them closer to modern standards.

Characteristics

Layout
Typically these homes have two reception rooms and a small kitchen on the ground floor, with three bedrooms and a bathroom on the upper floor.

The front door opens onto a hallway, which contains a stair to the upper floor. Three doors off this hallway lead to a sitting room at the front of the property, a dining room to the rear and a kitchen that sits behind the hallway.

Upstairs the plan follows largely the same layout, with a bedroom sitting over both the dining room and sitting room and a bathroom sitting over the kitchen. A third, smaller bedroom sits at the front of the property, over the entrance area below.

Typical Ground Floor Plan

Typical First Floor Plan

Construction
It was during this era that cavity wall construction became the norm for external walls. Typically, these would consist of two single brick walls, either side of a slim uninsulated cavity (50-75mm), held together with wall ties. External render was also common, usually to conceal walls constructed from concrete or clinker blocks. Load-bearing walls were typically built on concrete strip foundations. 

At ground floor, the internal walls were also constructed with brick or block work to support the upper floors. In some cases, the load bearing walls extend to the upper story to support the roof. Internally walls were finished with plaster. Non load-bearing walls on the upper floor were typically timber stud walls. Homes constructed prior to 1940 may still lath and plaster walls and ceilings. However, plasterboard was introduced in the 1930s and had largely replaced lath and plaster by the end of the decade.

While suspended timber ground floors continued to be standard in this era, tongue and groove floorboards replaced square edged boards, making the floors less draughty than their Victorian counterparts. Timber joists, supporting tongues and groove floor boards, were also used to construct the upper floor.

Roofs were usually a hipped timber purlin structure, clad with clay or slate tiles. Originally these houses would have featured cast-iron gutters and drains, though in most cases these have likely now been replaced with plastic alternatives. External doors and window frames were typically timber, but again many of these have now been replaced with uPVC.

Original features may include:

• Tiled fire places

• Decorative stained glass

• Timber panelling, doors and other fixtures

Benefits

1930s semidetached houses are typically located in suburban areas, close to schools and other useful amenities. Their suburban location means they tend to sit on large plots, providing potential to extend. Additionally, it is common for these properties to have large loft spaces that are generally uncomplicated to convert into  habitable space.

Disadvantages

As with older properties, 1930s houses were still typically constructed with suspended timber ground floors. These can be susceptible to rot if the void beneath is not adequately ventilated. Be sure any air-bricks or vents remain unblocked.

Internal alteration can be slightly complicated in comparison to contemporary properties as some or all of the internal walls are likely to be load-bearing. This doesn’t completely rule out making internal alterations, it just means you must make sure changes do not impact the structural integrity of your home and alterations to load-bearing walls will require Building Regulations Approval.

Potential Improvements

Cutaway of an altered mid-century semi

Insulate
Most older properties can benefit from improved or additional insulation. Insulation can be added to the cavities within the external walls, however this must be done by a professional and requires building regulations approval. Insulating the void beneath the ground floor and the loft space are also great ways to improve thermal performance. It is important the correct techniques and products are used when installing insulation to avoid potential issues with condensation.

Alter
Small internal changes can go a long way in making your home work for you. For example, homes of this era typically have relatively small kitchens, as at the time they were considered purely functional, utilitarian spaces. Removing the wall between the kitchen and dining room could create a more open space, better suited to modern lifestyles. Remember, the internal walls at ground floor level are likely to be load-bearing so seek appropriate professional advice before undertaking any work.

Extend
Typically sitting on large plots, these houses are often well-suited to extensions. A rear extension, running the width of the property, could further enhance your ground floor space creating a fully open plan living area. You’ll want to keep this single storey though, to ensure enough daylight can reach the interior spaces.

Example of ground floor with wrap around extension

Example of first floor with side extension and new stairs leading to habitable loft

The side of the property may be a good location for a two storey extension. The layout of these properties means it is often fairly straightforward to plan these new spaces, without requiring alteration to the layout of the existing property. Loft conversions are another great option to further maximise your space.

To discover ways you may be able to extend your home without applying for planning permission, see our article on permitted development.

Final Word

Well located and generally on large plots, mid-century semi’s can make great family homes. Existing cavities can provide the perfect location to add wall insulation, making your home more sustainable and potentially cheaper to run. While the load-bearing internal walls can add complications when considering alterations, the simple layout and large plots make these houses highly adaptable. Just remember, before undertaking any structural work seek professional advice. Building control approval will likely be required.