Remodelling the 1930s semi: what the street gains and what it loses

Few house types divide opinion like the remodelled 1930s semi. Critics argue that modernisation strips these homes of their period features and leaves suburban streets lined with pale rendered boxes that all look alike. The irony that the houses looked identical when they were built is often lost in the argument. Homeowners and the people who design for them argue that an unaltered 1930s semi is cold and cramped by modern standards, and that a house has to work for the family living in it. Both sides have a point, and the best schemes take something from each.

The case for remodelling

The strongest argument is thermal performance. Most 1930s semis were built with cavity walls that were left empty and with single glazing throughout. The ground floor is usually suspended timber over a ventilated void, which lets draughts come straight up through the boards. Original steel windows, where they survive, lose heat badly and run with condensation in winter. Cavity fill, external wall insulation, floor insulation and new glazing can transform running costs and comfort. External wall insulation is usually finished in render, so some of those white boxes are white because they have been wrapped in insulation.

Layout is the second argument. The 1930s plan was built around a front parlour kept for best and a small back kitchen with no room to eat in. Upstairs, the third bedroom is a box room over the hall. That arrangement suits few households now. A rear extension with the kitchen opened up to the dining room, and perhaps a loft conversion above, turns a cramped three-bedroom house into a family home with room to grow, which keeps families in established suburbs.

Remodelling also keeps the building standing. Upgrading an existing house avoids the embodied carbon of demolition and rebuild, and the structure of a 1930s semi is generally sound enough to justify the investment. The work often deals with neglected problems at the same time, such as failing pebbledash and rusted window lintels. A house modernised this way usually sells for more.

The case against

The critics' point about sameness deserves more attention than it usually gets, because it cuts both ways. The speculative builders of the 1930s did sell near-identical houses, but they designed them as matching pairs repeated along the road, so the street read as one composition. Walk past a run of semis with bay windows, recessed porches, hipped roofs and tile-hung gables and you can see the rhythm. Give one half of a pair a hip-to-gable loft conversion and white render, leave the other half in red brick under its hipped roof and the houses no longer match. Repeat that along a street and the rhythm falls apart. What the critics are objecting to is the loss of cohesion, and on that they are right.

Because the houses were modest, the details carried most of the character. Builders set one estate apart from the next with sunburst stained glass, leaded lights, decorative brickwork, tile hanging, oak front doors and original windows. Remove those and very little is left to tell you when the house was built. Putting them back is expensive.

There are technical risks as well. Render or insulation in the wrong materials can trap moisture in older brickwork and cause damp the original construction never suffered from, and chunky uPVC frames change the proportions of a front elevation more than most owners expect. Much of this work falls under permitted development, so outside conservation areas there is very little design control over how any of it is done.

Front gardens and flooding

Part of the critics' complaint is aimed at the front garden. Many 1930s homes have had their lawns and hedges replaced by hard paving for parking, and the consequences go further than looks.

In England, paving more than five square metres of a front garden with an impermeable surface needs planning permission unless the rainwater drains to a permeable area within the property, such as a lawn or a soakaway. The rule has been in place since 2008, but it is rarely enforced and many fully sealed driveways went in without challenge.

The flooding problem is cumulative. One paved garden makes little difference, but a whole street of them sends rainwater straight into drains designed for a suburb of lawns and hedges. In heavy storms those drains overflow, and where sewers are combined the overflow carries sewage into rivers. Front gardens also keep the street cooler and give wildlife both a haven and a corridor.

Parking and planting can coexist. Permeable block paving looks like a conventional driveway but lets water through its joints into a gravel sub-base. Gravel over a stabilising grid is cheaper and also drains freely. Grass-reinforced grids support a car while staying green. Two paved wheel tracks with planting between them suit narrower plots and echo the original driveways of the period. A planted strip along the boundary, or the original front hedge kept in place, softens a rendered frontage more than any architectural detail.

Where we stand

Our role is to deliver the home the client wants, and the decision is theirs. Where we can, we advise keeping some green at the front and treating the street elevation with care. The better schemes put their ambition into the rear extension and the interior. At the front they keep the bay and the roof form, and they keep the original windows or replace them with something close in proportion. Insulation can go on the inside of the front wall, or beneath the floor, without changing the face of the house.

Done that way, a remodelled 1930s home can perform like a modern one and still sit comfortably beside its unaltered twin.

By Joe Garner MRICS

Director