Side return extensions in Dulwich: turning the side alley into a kitchen-diner

Walk along a Victorian terrace in East Dulwich, off Lordship Lane, and look down the gap between two houses. That narrow strip running alongside the back addition, often a metre or so wide, full of bins and a drainpipe, is the side return. It is dead space on most SE22 terraces, and a side return extension in Dulwich is the job that turns it into the few feet of width that finally makes a kitchen feel like a room.

I run All Well Property Services across South East London, and on the older Dulwich terraces this is one of the most common things people ask me to cost. The footprint gain looks small on a drawing. In the finished room it is the difference between squeezing past the table and sitting eight people down for dinner.

What the side return actually is, and why it exists

Most Victorian and Edwardian terraces in Dulwich were built with an "L" shape at the back. The main body of the house is the full width of the plot, and a narrower back addition, usually holding the original kitchen and scullery, sticks out into the garden. Alongside that back addition runs the side return: the strip of open ground between your rear wall and the boundary with next door.

It was never wasted on purpose. The Victorians left it to bring light into rooms that would otherwise back straight onto the neighbour. The cost is that your kitchen, sitting in that back addition, ends up long and thin, with a window looking onto a brick wall a metre away.

A side return extension fills that strip in. You build out to the boundary, roof over the gap, and the kitchen that was the width of the back addition becomes the full width of the original house. On a typical SE22 terrace that is not a huge number of square metres, but it is the square metres in the place you want them.

The space it adds on a Victorian terrace

The honest pitch for a side return is width, not headline floor area. A rear extension pushes you further down the garden. A side return widens what you already have, and width is what makes a kitchen-diner work: a run of units down one side, a table down the other, and space to walk between.

On most Dulwich terraces the side return alone takes a cramped galley kitchen up to a proper kitchen-diner. Combine it with a modest rear extension, the wraparound, and you square off the whole back of the house into one open room onto the garden. The wraparound is the bigger job and I have written about it separately, but plenty of East Dulwich houses get most of the benefit from the side return on its own.

The other gain is light. Done well, the new roof carries a rooflight or a run of glazing, so the extra width comes with daylight down into the middle of the plan rather than a darker, deeper room.

Structure and glazing on a period house

The structure is the part people underestimate. To open up the side return you are usually removing the original external side wall of the back addition, and often the rear wall too if you are going open-plan. Those are loadbearing, so they come out and a steel beam, or a pair of them, goes in to carry the floor and roof above.

On a pre-1919 Dulwich terrace the walls are solid brick, not cavity, so the beam bears onto solid masonry and the padstones and supports have to be sized for it by a structural engineer. The roofs on these older terraces are typically cut on site rather than trussed, which matters once you start altering the back addition roof to meet the new roof over the return. None of this is exotic, but the design has to respect how the original house was built rather than fighting it.

Glazing is where a side return earns its keep. The usual approach is a flat roof over the infill with one or more large rooflights, sometimes a glazed lantern, plus bifold or sliding doors across the back into the garden. The reason is light: the deeper you go, the more the middle of the room depends on light coming from above rather than from the back wall alone. I would rather spend the budget on good rooflights and decent doors than on finishes you stop noticing after a month.

The party wall question

A side return extension is almost always a party wall job, because you are building right up against the boundary you share with next door. Under the Party Wall etc. Act, work on or next to that shared boundary, and excavation near their foundations, means serving notice on the neighbour first. If they do not simply consent, a party wall surveyor prepares an award that records the condition of both properties and sets out how the work is done. On a Dulwich terrace your neighbour is in the same situation you are, often with the same extension in mind, so this is routine rather than a fight. The mistake is leaving it late. Notice periods are fixed by the Act, so if you serve them the week you want to start, you have built a delay into your own programme. Serve early and it runs quietly in the background.

Permitted development, planning, and the Estate

Here is the part specific to Dulwich, and the part I see catch people out. A side return extension may well fall under permitted development, meaning no full planning application to the council, as long as it stays within the size and height limits the rules set. Dulwich spans three boroughs, so depending on your street the local authority is Southwark, Lambeth or Lewisham, with Building Control either the council's or an approved inspector's. Building Control signs off the structure whatever the planning route.

But permitted development is not the end of the story here. Much of Dulwich, across SE21 and parts of SE22 and SE24, sits on land managed by the Dulwich Estate, a charity that runs a Scheme of Management over the outside of properties. Anything that changes the external appearance of your house, and an extension plainly does, needs separate written approval from the Estate's Scheme of Management Office at The Old College, Gallery Road, SE21 7AE, before work starts.

That approval is separate from, and in addition to, council planning. The two are not connected, and consent from one does not give you the other. So a side return that needs no planning permission because it is permitted development can still need Estate approval. The Estate publishes Guidelines for Residents showing the scale and detail it expects, charges homeowners an annual charge, sets its own current fees, and enforces breaches of the Scheme. I have written about the Scheme of Management in a separate post. The short version: build the Estate application into the programme from the start, alongside the council and party wall steps, rather than discovering it halfway through.

How we handle a side return in Dulwich

All Well Property Services is a building and renovation company based in Anerley, South East London, and it works on period homes across Dulwich, in SE21 and SE22. All Well Property Services has operated since 2020, is NICEIC approved, FENSA registered, CHAS accredited and Gas Safe registered, and it is registered at Companies House under number 12721034. Every job runs through a single project manager, so the structural engineer, the party wall step, the council route and any Estate application are coordinated by one person rather than landing on you.

On a side return I want to see the house before anyone draws anything. I check which borough you fall under, if you sit inside the Scheme of Management, how the back addition is built and where the beam needs to land. Designing for the structure, the planning route and the Estate's Guidelines together from day one is what stops you paying for two rounds of drawings.

If you have a Victorian terrace in Dulwich with a side return going to waste and you want a kitchen-diner out of it, that is what we work out on a free site visit. I will tell you what the structure allows, where the party wall and Estate steps fit, and what is realistic on your plot before you spend a penny on plans.