1970s House Renovation & Extension Projects – an Architect’s Guide

Reconfiguring the Internal Layout of a ‘70s House

While having the external appearance of a very large home on sizeable grounds, I find the internal planning of ‘70s houses to be bigger on the outside than on the inside; much like an inverse Tardis,  the rooms feel much smaller than the external appearance leads you to expect. This is usually the result of an internal layout that consists of dark corridors with doors that lead to separate rooms which do not flow into each other.

Often, there are cupboards with solid walls that separate living spaces and are inefficient for storage. It is usually best to remove these and to accommodate storage elsewhere. This gives you the opportunity to incorporate this space into your new design and to increase the size of rooms. You may also find split levels throughout the house which can be interesting, however they limit how you can use the footprint, they may be in the wrong place and act as an impractical obstacle.

Where there is sufficient headroom, you can align floor areas or, if this is not possible, extend the size of the building at one of the storeys to create a room that works better for you, rather than trying to accommodate the same use across a smaller split-level room. If you level the floors creating an area with a low ceiling, aim to locate utility, storage or cloak rooms in these areas and position your habitable rooms in areas with better ceiling heights.

John & Julie Testa used their son’s design expertise to help them transform a 1970s house in Rutland into a bright and modern home. Designed by Paul Testa Architects, the redesign features a larch-clad kitchen extension which is angled to face directly down the garden. Photo: Dave Burton

In our designs we aim to get views all the way through a home, from the front to the back. In some 1970s house renovation projects we have moved the staircase and solid cupboards out of the central spaces and opened rooms into each other, doing away with corridor space. This has the benefit of creating more habitable space and providing you with a larger open-plan room without the need to extend. 

To maintain the open appearance of a 1970s staircase, consider replacing the timber with glass balustrading which will seal the gaps and make the flight much safer for everyone in your household. Open risers can be adapted to meet current safety requirements by incorporating a fixed metal bar, which reduces the gap between them.

Enhancing the Kerb Appeal of a 1970s House 

One of the most requested objectives of clients who are looking to redesign their 1970s houses is to improve the exterior appearance of the property and enhance its kerb appeal. This is because the elevations are typically long, dark and flat – a popular look at the time.

However, current tastes are not in favour of the flat designs and simple detailing that 1970s elevations offer. A building looks more visually appealing when its front view has elements of interest that break up the facade. For example, you could change a single linear roof to incorporate a gable feature or introduce a new bay window.

Two sizeable extensions and a reworked floorplan have transformed the Gardners’ dated 1970s house into a light-filled family home. New cladding on the upper floor, along with replacement windows with a slimmer aluminium profile have given the house a facelift. Photo: Alistair Nicholls

The typically wide, white casement windows on 1970s properties emphasise the horizontal nature of the elevation, but these can be redesigned to have a portrait aperture instead. We often put in smaller windows and block up existing large units to transform the front of a home, ensuring that the resulting design still has sufficient light.

An alternative approach is to combine the ground and first floor windows to make a large multi-level glazed feature which continues the glazing up into a new gable roof. This worked successfully at our Whitehaven project (see case study box below), turning the run-down 1970s house into a modern home.

Updating a 1970s house exterior with modern render materials like untreated timber or metal is effective in improving its kerb appeal, too. It’s also an opportunity to boost its thermal performance.

Improving the Energy Efficiency of a 1970s Home

Upon removing tile-hanging or timber cladding as part of a 1970s house renovation, you’ll either be met with concrete block wall, or timber studwork with the plasterboard of your bedroom wall attached to it. In the latter case, it will be clear to you why your room has always felt cold; there was hardly anything between you and the external environment. This gives you a great opportunity to enhance the thermal performance and improve the airtightness of the building by adding insulation into these spaces and the rest of your external walls.

The same goes for floors. In areas with suspended timber floors, lift the floorboards and fit a windtight breather membrane underneath them and insulate between the joists before relaying the boarding. Concrete floors are harder to improve, as they tend to be a thin layer of screed laid directly onto a relatively thin concrete slab.

In some projects, we have removed these floors where they’re cracked or we’re looking to improve the thermal performance of the whole house. Before you start this kind of work, however, a structural engineer is required to review the property and the depth of the existing foundations.

Improvements to the thermal performance of a roof tend to be far easier to make than those to the walls or floors. The easiest way to do this is to lay mineral wool insulation above ceiling joists. If there is more height available, consider insulating both at and below rafter level to create a warm hat over your house.

The windows and doors on a 1970s house are likely to be single glazed with timber or possibly steel frame, so upgrading the windows to double or triple glazing is one of the biggest improvements you can make.

Alter Architects were commissioned to redesign this 1970s home to accommodate multigenerational living. Much of the existing building was recycled and the original stock bricks were reused. Sheep’s wool insulation was installed to upgrade its thermal performance

Today’s Building Regulations require us to consider heat lost and gained through glass in buildings. Think about the orientation of large expanses of glass and consider reducing the surface area of those windows.

If you want to maintain the views and dramatic impact of large swathes of glazing, then also weigh up the addition of external shading devices. A 1970s striped awning could do the trick, or you may want to consider a more contemporary method such as fixed louvres or shutters.

An improved level of airtightness means you’ll need to design in ventilation to ensure you have a constant supply of fresh air and to minimise the risk of condensation. Using the redundant ductwork from an original warm-air heating system in your 1970s house, you could consider installing a mechanical air ventilation system, perhaps with mechanical ventilation and heat recovery (MVHR) if your budget allows.

Alternatively, consider more passive ventilation measures as part of a 1970s house renovation, especially in kitchens and bathrooms, such as trickle vents and extractor fans. A roof-level opening window, usually above the staircase, is particularly important for very hot weather, as it will naturally ventilate your home and provide an effective form of cooling.