AI-led strategy for a tricky infill site in Harborne
Lapworth Architects were appointed by a private residential client to test the potential of a tight side-garden plot in Harborne, using outline planning to establish whether new flats could be accepted in principle. The site sits in a typical suburban street of two-storey blocks and houses, and the project is framed for clients looking for architects in Harborne and the wider Birmingham area who need a clear strategy for difficult infill plots.
The existing plot reads as an underused strip of land between two flat blocks, with deep gardens to the rear and close boundaries on both sides. The street pattern is regular, with simple rectangular buildings, shallow front gardens and parking directly from the carriageway, so any new volume has to sit quietly between its neighbours while respecting daylight and privacy. Our brief is clear, to unlock value without provoking the usual objections about overbearing mass or loss of light that often arise on similar Harborne streets.
Key moves follow from the site geometry. Our design keeps the new building to one and a half storeys, sized at around 72 square metres with a private rear garden of about 45 square metres, so that the ridge line steps comfortably below the flanking two-storey blocks and the outlook from existing windows is maintained. The front elevation picks up the horizontal and vertical rhythms of the street with a simple entrance bay and grouped windows, while the plan arranges compact flats around a straightforward stair core, keeping primary rooms facing the garden and the street rather than side boundaries.
AI and AskArchi are central to the way we shaped this scheme. Working from the massing studies, our team used AI-assisted tools to iterate several envelopes over the same footprint, testing option after option for separation distances, overshadowing and internal layouts before settling on the preferred massing shown in the 3D views. This allowed us to evidence that a modest, well-proportioned infill block can sit between the existing flats without breaching common daylight guidelines or creating unreasonable overlooking, even on such a constrained plot.
The planning route is structured around an Outline Planning Application, reserving appearance, layout and landscaping for a later stage while asking the council to decide only on the principle of residential use. Working through UK Planning Gateway, we coordinate drawings, AI-generated analysis graphics and supporting statements into a single digital workflow, maintaining version control as survey data and consultant input on highways, drainage and daylight are refined during the application process.
This is a perfect example how we approach tricky infill sites as architects in Harborne and architects in Birmingham more broadly, using AI to explore massing and risk before committing to full design development. The same mindset carries across our work in nearby areas such as Edgbaston and Solihull, where modest, carefully scaled buildings can add new homes to established streets when the planning logic is robust and the architecture grows directly from the constraints of the site.
