Flitch House

The Flitch House.

Completion: 2023

Scope: To design and reinstate the entire second floor as a contemporary extension. Plus, a ground floor extension to create a new kitchen, dining, family room.

Type: Residential

Planning Issues; Grade II listed building consent with protected views.

Sustainable Points: Thermal performance improved to AD Part L1B Conservation of fuel and power in existing buildings

Client: Private homeowner

Consultant Team: Clay Architecture

Alan Baxter Partnership

Contractor: Gransden Construction

Flitch House is a Grade II listed 18th Century house located in a historic conservation area. It was originally a grand double bay fronted three-storey property. The southwest half of the house was demolished after it was burnt down by mutinous soldiers over a pay dispute, during the Food Riots of 1796. At the time, the house was leased to the magistrate responsible for withholding pay. The second floor and pent roof were removed and replaced with a stainless-steel flat roof by a previous owner in 1955 because it was in a very poor state of repair.

Flitch House was acquired in 2018 as a private home and the new owner appointed Clay Architecture to design and reinstate the second floor as a contemporary extension. This new space provides an open plan ‘pleasure lounge’ with stunning views of the nearby castle and river.

Pre-consultation with the local planning authority began in September 2018. Given the protected historic views and proximity to the castle, the Conservation Officer warned that listed building consent for the contemporary second floor extension the client desired would be feasible but challenging.

Extensions to Grade II listed Flitch House

flitch house

We worked closely with our client, with Planning Officers and Conservation Officers and with Historic England. Detailed pre-consultation took 10 months and several design iterations before a design was finally agreed. Listed building consent was granted with minor conditions, which is extraordinary given the significance of the house and the protected view.

The existing front masonry façade has been extended up to the second story, knitting into the surrounding roofscape and repeating the first floor windows and cornice. This reinstated period brick façade screens the contemporary second floor, maintaining protected views from the top of the castle towards the property. The new extension has an M-shaped butterfly roof and an open gable, a large modern picture window on the side with views of the river, and bi-fold doors opening on to a sun deck at the rear.

The new second-floor roof is a lightweight flitch rafter and flitch beam structure, which touches down at just a single point in the middle of the floor through a forked flitch V-post. This point is connected to spreader beams and half-forked posts at either end via a system of steel plates, ties and timber noggins concealed within the diaphragm floor.

In this way, the new second story extension spans the existing outer walls and sits on spreader flitch floor beams to ensure that no point loads are imposed anywhere on the historic, listed building structure below. Consultant engineer Alan Baxter Partnership commented that this design is at the very limit of what is structurally possible with a historic building of this kind.

A ground floor extension, completed in an earlier phase, creates a new kitchen, dining, family room. These projects have increased the area of the client’s home by a third and provide stunning views from the new second floor living space, while enhancing and extending the life of the listed building below, restoring it to its former glory through contemporary interventions.

Working on listed building projects, especially where there is potential to impact on a historic built environment or landscape, create unique challenges and opportunities. RIBA Conservation Architect Registrant and Clay Architecture Director, Camilla Prizeman comments; ‘This is an exciting opportunity to add a contemporary addition to a listed home that has a low impact on the property’s significance, on the conservation area and on protected views, while providing state-of-the-art living space.


For any inquiries please email


Gransden Construction

Gransden Construction