Side-return infill drawings for Dacorum terraces — the glazed extension that fills the redundant side alley and opens up the kitchen, drawn to Dacorum Borough Council's guidance, delivered in days and revised free until your decision, with a free approval-odds check first.
Dacorum Borough Council granted 87% of the householder planning decisions it made in its latest published year — level with the 87% England-wide householder average. Extensive Metropolitan Green Belt covers the rural borough, concentrating growth on the three main towns and allocated sites, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Victorian (1837–1901), interwar (1918–1939) and postwar (1945–1970) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Dacorum carries at least one Article 4 direction, and conservation areas including Hemel Hempstead Old Town, Berkhamsted and Tring remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Dacorum is determined against an 8-week statutory target.
Hemel Hempstead (a postwar New Town of planned neighbourhoods around the Marlowes centre), Berkhamsted (a historic canal-side market town in a Chilterns setting), Tring (a historic market town at the Chilterns gap), Kings Langley (a historic commuter village with a conservation-area core), Aldbury (a model rural conservation village below the Chilterns) and Bovingdon (a rural Green Belt village) — these are the Dacorum pockets our drawings cover most. Heritage designations here include Hemel Hempstead Old Town, Berkhamsted, Tring, Aldbury, Kings Langley and Bovingdon. Dacorum Borough Council weighs each proposal against the Dacorum Core Strategy 2006–2031 (adopted September 2013), where the Chilterns National Landscape (AONB) covers and adjoins Berkhamsted and Tring, adding landscape-protection constraints on design and siting. Converted and purpose-built flats appear across Hemel Hempstead and the town centres, and none of them hold householder permitted-development rights.. On roofs the borough is pitched tiled roofs on the postwar New Town housing and steep tiled and gabled roofs on the historic market-town and village cores, over postwar New Town planned neighbourhoods across Hemel Hempstead around the Marlowes centre, medieval, Georgian and Victorian market-town cores at Berkhamsted and Tring, interwar and Victorian stock and vernacular cottages in the surrounding villages and larger detached housing on the Chilterns fringe.
The side return is the classic terrace fix, and Dacorum has the stock for it — the borough is built largely from postwar New Town planned neighbourhoods across Hemel Hempstead around the Marlowes centre, medieval, Georgian and Victorian market-town cores at Berkhamsted and Tring, interwar and Victorian stock and vernacular cottages in the surrounding villages and larger detached housing on the Chilterns fringe, and the Victorian and Edwardian versions almost all have an L-shaped back addition with a wasted alley beside it. Fill that alley and the dark galley kitchen becomes a bright, square room the full width of the house. Dacorum Borough Council judges the infill against the Dacorum Core Strategy 2006–2031 (adopted September 2013), and because it runs along the party boundary, the neighbour relationship is read before the design.
That boundary is where the drawings earn their keep. We set the infill wall on or up to the line, keep the roof — usually a glazed lantern or a shallow pitch tying into the existing back-addition slope — below the neighbour's first-floor windows, and detail the rainwater and party-wall junction so the build is watertight and the Party Wall Act is satisfied. Extensive Metropolitan Green Belt covers the rural borough, concentrating growth on the three main towns and allocated sites, so we resolve it on the section rather than leave it to the case officer.
Many of Dacorum's terraces sit in conservation areas — Hemel Hempstead Old Town, Berkhamsted, Tring, Aldbury, Kings Langley and Bovingdon among them — where a side extension is no longer permitted development. Dacorum's Article 4 directions, confirmed in November 2022, cover employment and town-centre areas and retain the requirement for planning permission to convert identified properties to residential use, and the borough's twenty-five conservation areas add further character controls. We confirm the designation before a line is drawn.
Some single-storey side returns in Dacorum are permitted development, but the width and boundary make an application more likely than for a straight rear extension. You will normally need to apply to Dacorum Borough Council if any of these apply:
We draw the infill wall on the boundary, the glazed roof below the neighbour's windows and the party-wall junction on the page — the details Dacorum Borough Council's officers and your neighbour both check — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Dacorum Borough Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Dacorum grants a fair share of householder applications, with green-belt containment, the Chilterns AONB and its many conservation areas the recurring constraints on larger schemes. Side returns hinge on width, roof glazing and the party boundary, so a pack that resolves those details upfront is decided faster and refused less often than a DIY submission.
Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
Across Hemel Hempstead, Berkhamsted and Tring, the approved side return is a single-storey infill roofed with a glazed lantern or roof light to pull daylight deep into the plan, its flank wall built on the boundary and finished to match the host brick. On the borough's postwar new town planned neighbourhoods across hemel hempstead around the marlowes centre, this is frequently the single biggest gain in usable ground-floor space, and where it stays within the width and height limits it can proceed under permitted development or a lawful development certificate.
The Chilterns National Landscape (AONB) covers and adjoins Berkhamsted and Tring, adding landscape-protection constraints on design and siting. We keep the glazed roof below the neighbour's cill line, set the gutter and the party-wall flashing so water and maintenance are designed in, and — where owners want the full open-plan room — pair the infill with a rear extension as a single wraparound application. That way Dacorum Borough Council sees one coherent scheme rather than two overlapping ones.
We draw side-return infills on every terraced street in the borough. A few of the neighbourhoods where Dacorum side returns come up most often:
Side return extension drawings for Hemel Hempstead's a postwar New Town of planned neighbourhoods around the Marlowes centre — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Side return extension drawings for Berkhamsted's a historic canal-side market town in a Chilterns setting — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Side return extension drawings for Tring's a historic market town at the Chilterns gap — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Side return extension drawings for Kings Langley's a historic commuter village with a conservation-area core — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Side return extension drawings for Aldbury's a model rural conservation village below the Chilterns — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Side return extension drawings for Bovingdon's a rural Green Belt village — width-checked, party-wall detailed and drawn to Dacorum Borough Council's guidance.
Whether a side return in Dacorum needs permission comes down to width, storeys and whether the street is designated. This is how the cases compare.
| Side return type | Permitted development? | What it gains | What Dacorum Borough Council checks |
|---|---|---|---|
| Single-storey infill, within limits | Often yes, if under half the house width | Full-width kitchen-diner | Width, 4m height, roof glazing |
| Single-storey, over half width | No — full application | Wider room, more light | Boundary treatment, neighbour amenity |
| Two-storey side return | No — full application | Room above as well as below | Bulk, overlooking, terrace rhythm |
| Wraparound (side + rear) | No — full application | L-shaped open-plan ground floor | Combined footprint, garden retained |
In conservation areas such as Hemel Hempstead Old Town and Berkhamsted, side extensions are not permitted development and always need a full application.
A fixed process built around how Dacorum Borough Council validates and decides side-return applications — most drawings are submission-ready within seven days of survey.
Send us your Dacorum postcode and terrace type. We confirm your conservation and Article 4 status, whether the infill stays within the side-extension width limit, and score your odds against live Dacorum Borough Council decisions.
We measure the side alley, the back-addition wall, floor and eaves levels and the neighbour's window heights — the numbers the width limit, roof pitch and party-wall detailing depend on.
Chartered designers develop the infill and its glazed roof to your brief, drawn inside the permitted-development limits or to Dacorum Borough Council's extension guidance, with the boundary and party-wall junction detailed.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Dacorum Borough Council issues its decision.
Sometimes not. A single-storey side-return infill can be permitted development if it is no wider than half the original house, no higher than 4 metres, and the property is not on designated land. In Dacorum you will need a full application to Dacorum Borough Council for anything wider or taller, for a two-storey side return, and for any side extension in a conservation area such as Hemel Hempstead Old Town and Berkhamsted, where those rights are removed.
It is an infill that fills the narrow open alley running alongside the rear back-addition of a Victorian or Edwardian terrace — the strip of ground that is usually too small to use. Building over it squares off the ground floor, so a cramped galley kitchen becomes a full-width room. Dacorum's period terraces are ideally suited to it, which is why the side return is one of the borough's most common extensions. Dacorum Borough Council is the decision-maker.
Almost always. A side return is built on or up to the boundary with your neighbour, so the Party Wall etc. Act applies and you must serve notice before work starts — this is entirely separate from Dacorum Borough Council's planning decision. We detail the party-wall junction on the drawings and flag the notice early so a surveyor can be appointed without delaying the build.
Yes, and it is common — the combined L-shape is a wraparound extension. Once the side infill joins a rear projection beyond the permitted-development depth, the whole thing needs a full householder application to Dacorum Borough Council rather than qualifying as permitted development. We draw it as one coherent scheme so the council assesses a single footprint, which reads more clearly than two overlapping proposals.
A householder planning application in Dacorum runs to a statutory eight-week target, and a lawful development certificate to eight weeks as well, though an incomplete pack can stall at validation. Because a side return involves the boundary and roof glazing, a complete, well-detailed submission matters — we prepare it validation-complete and manage officer queries to keep the decision on track. Dacorum Borough Council is the decision-maker.
We price each Dacorum side return individually, because alley width and roof form vary house to house, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Dacorum Borough Council approves, and we confirm at the outset whether your infill is permitted development or needs an application. Call 020 7864 7245 to start.
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