Akenside Road, Hampstead
3 Akenside Road, NW3 5BS
Project overview
The Project
The property is an Edwardian building in Hampstead. It’s arranged as three separate flats across the ground, first and second floors. AC Design Solution was appointed to take over the technical delivery of a structural reconfiguration of the ground- and first-floor flats. The brief included a single-storey rear extension and a first-floor roof terrace, within the Fitzjohns/Netherhall Conservation Area.
The client had concerns about a previous appointment. The drawings in place had incorrect dimensions. Internal walls had already been removed. No trial pits had been carried out to check the foundation conditions. The client knew our team because we were already working on another property further along Akenside Road, and asked us to take over. Our brief covered:
- Architectural design
- Structural engineering
- Building regulations
- Party wall matters
Throughout, we had to maintain the structural support, fire separation and acoustic separation required for the second-floor flat above.
Drawings and project imagery
Project Gallery
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Selected architectural drawings, technical details and project views from the coordinated design package.
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Spatial design
Architectural Design
When we were appointed, internal walls had already been removed. The earlier drawings’ dimensions didn’t reliably match the building. We carried out a site review and rebuilt the drawing package from verified measurements. We reconciled the consented rear extension and terrace with the property’s real dimensions, levels and structural arrangement. That gave the architectural, structural and building regulations packages one dependable base to work from, instead of separate information built on conflicting assumptions.
At ground level, the rear extension created a larger open-plan kitchen, dining and living space with a direct connection to the garden. At first-floor level, the reconfiguration included:
- A new terrace over the extension’s roof
- A wider restructuring of the flat’s layout
- Coordination with the retained walls, structural openings and the second-floor flat above
Within the Fitzjohns/Netherhall Conservation Area, the design followed the form and external appearance of the approved scheme. It also resolved the junctions and construction detail needed to actually build it.
Engineering coordination
Structural Engineering
No trial pits had been carried out before the earlier structural information was prepared. That meant the depth, condition and configuration of the existing foundations hadn’t been verified before internal demolition and structural opening-up began.
We arranged trial pits after our appointment. This let us design the extension’s foundations around what was physically there, rather than an assumed arrangement. That mattered most where the extension met the existing rear wall, and where loads from the altered layouts had to transfer safely through the retained structure.
Our structural engineering team reassessed the structural arrangement across both floors. We reviewed which walls had already come out, established what they’d previously supported, and traced the loads through the altered building.
The permanent design covered:
- New steel beams supporting retained floors and walls
- Load transfer around the enlarged ground-floor openings
- Structural support for the first-floor reconfiguration and the terrace
- Bearing positions and supporting masonry
- The relationship between the extension’s foundations and the existing building
Every part of it was developed against the corrected survey and the trial-pit findings — not the dimensions the earlier drawings had got wrong.
Technical compliance
Building Regulations
We produced the building regulation drawings package for the ground- and first-floor restructuring, the rear extension and the terrace. It brought the corrected architectural and structural design into one coordinated set of information, covering:
- New structural openings and steelwork
- Extension and terrace construction
- Thermal performance
- Above- and below-ground drainage
The terrace needed its own coordination on top of that: structural loading, waterproofing, drainage falls, threshold details and guarding, all without compromising the weatherproofing of the extension roof below. Because the building remains subdivided into three flats, fire and acoustic separation between dwellings had to be maintained throughout the altered floors.
Our appointment continued during construction. We responded to contractor queries and reviewed conditions uncovered through opening-up against the drawings and calculations, while building control carried out the statutory inspections.
The Building Control application had originally been submitted by the construction company. That company went into insolvency before the process was finished, leaving the file open for several years with no one to close it out. When formal certification became necessary for a property-finance transaction, we reopened the outstanding matters. We coordinated the information Building Control needed and took an application we hadn’t originally submitted through to completion. Camden Building Control issued the completion certificate on 24 September 2025, under application 23/5R/02234.
Neighbouring property matters
Party Wall
The rear extension, terrace, foundation works and structural alterations brought the project within the scope of the Party Wall etc. Act 1996. AC Design Solution provided the full party wall surveying service as part of the wider appointment, rather than the client having to coordinate a separate surveyor unfamiliar with the structural works. Party wall surveying led by Zubear Ali at AC Design Solution.
Consent and delivery
Project Outcome
When AC Design Solution took this on, construction had already started. The drawings didn’t match the building. The foundations hadn’t been investigated. The Building Control file would later sit unresolved for years, after the original contractor went under.
Our job was to replace all of that with verified information:
- Measured drawings
- Trial-pit evidence
- A coordinated structural and architectural package
- A Building Control application we hadn’t submitted, carried through to a certificate
Construction itself finished in 2022 — a single-storey rear extension, a first-floor terrace, and a structural reconfiguration of the ground- and first-floor flats. The second-floor flat above stayed properly supported and separated throughout. The completion certificate followed years later, in September 2025, once it was needed for a property-finance transaction — closing out a file left open since the original contractor’s insolvency.
If you’ve inherited an extension, conversion or restructuring project where work has started but the drawings and structural information can’t be relied on, get in touch and we’ll look at how we can bring it back under control.
Written by Zaeem Chaudhary BA (Hons), LLB, MCIAT, Director and Chartered Architectural Technologist at AC Design Solution Ltd. Party wall surveying led by Zubear Ali.
