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Infill sites: a profitable way to fill pipeline voids


With the housing shortage being well documented it can be easy to assume that the only solution is to stack them high and create flats. This has been exacerbated, particularly in cities like London, where we have also seen many properties being converted into flats, meaning that there is a dearth of family housing available.

One area that has the potential to make a significant contribution is infill sites. These are often, smaller sites usually already among residential housing which can be repurposed with clever design as housing schemes. The potential to deliver significant amounts of housing on these types of sites is huge and often overlooked by large developers with appetite only for the largest sites, delivering to them economies of scale.

Whether looking to build a large scale development of more than 50 flats or a handful of houses there will still be the requirement to secure planning permission from the local authority. However, family housing is chronically undersupplied in the London market in particular, and the benefits of providing this along with the repurposing of tired assets, often means local authorities will consider fast tracking or even delegating the planning decision – especially for a scheme which provides private amenity space, particularly valuable following COVID-19. From a developer’s point of view this means a significantly quicker planning process allowing them to get on and deliver. Low rise housing schemes offer better scheme efficiency, lower build cost and shorter build time when compared to flat developments.

I’ve been working with a number of developers who are pursuing infill sites, diversifying their development opportunities to maintain consistent delivery and adaptability within an unpredictable market.

Handling infill sites successfully 

Turning infill sites into a profit can be challenging. Land, in cities especially, is at a premium, and many potential infill sites are overly restricted through planning policy as well as neighbouring land uses. Making an infill site work comes down to the careful balance of understanding what housing can be delivered on the site, understanding the costs of delivery and crucially being able to negotiate successfully with the landowner. Infill land works well in London where housing is in short supply and values of residential property often significantly outweigh other land uses - this type of development opportunity is not transferable to every UK city.

However there are a few pointers that can help when embarking on an infill residential development.

To deliver the most valuable scheme and get the most out of the available site, it’s essential to engage a good architect who can maximise the number of houses which can be achieved on the site. It must also be efficient to build; award winning design without consideration to cost and the ability to delivery the scheme is only going to affect the profit and deliverability. Early engagement with the local authority is key to understand what is deliverable and to ensure clear messaging from the start. A good planning consultant with experience with the planning authority is essential to manage this relationship.

Family housing is high on the agenda for most, and infill sites offer the means to make the most out of underutilised plots of land to help meet the continued demand on housing supply.


About the Author

James Burke, associate director in our residential team, specialises in residential development agency, including acquisition & disposals advice, providing development appraisals and marketing & sales advice for both private and public sector landowners. For further information about selling or buying infill in London and the south east do get in touch -

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James Burke


Residential - Development

London - West End

James has worked within the property sector since graduating from University in 2010. Initially working in the UK Retail Development sector. James joined Colliers International in 2013 and Heads the Residential Development team.

James has worked on a range of projects for both private and public sector clients across the south of England, helping clients maximise the value from their assets through strategic development advice and considered disposal strategies. James specialises in residential development agency, including acquisition & disposals advice, options analysis and modelling, site specific marketing & sales strategies tailored to our private and public sector landowner clients.  

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