Last edited 02 Feb 2021

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Alterations and extension to The Grange

The concept of the project was to reinvigorate a dated traditional dwelling house and create a contemporary ‘family hub’ section for our clients growing family to enjoy mixed internal use and also create a direct interaction point with their garden.

The grange interior.jpg

This was achieved by creating a simplistic contemporary insertion to the private garden façade of the dwelling, utilising a mixture of traditional materials such as slate roofing with VM Zinc clad fascia’s and posts along with high-performance aluminium clad windows forming the main exterior fabric. The original kitchen was absorbed into the new ‘hub’ with the large-scale removal of the former external walling, in addition, the former structure was stripped out, with new super insulated walls, along with the full replacement insulated floor accommodating a new underfloor heating system.

The design creates a large multi-use and adaptable space providing a mixed kitchen/dining/lounge, with a simplistic link to the main dwelling, forming an open light and spacious area utilising mixed solar gains. The main frame was formed from a simple steel frame built from poured concrete pads which created a quick construction timeframe further protecting the existing dwelling, all being clad externally with folded seam zinc cladding prior to installation of new high-performance windows and sliding-door screens.

The original building was formed from large stone walls abutting suspended timber floors and open roof space, we identified this as a serious performance issue and removed the main leakage points re-forming both floor and walls as highly-insulated and airtight structures, as well as over insulating roofscapes and sealing against existing new adjoining structures. Due to the nature of the project we had to carry out on site adjustments to the main junction points once these were uncovered, ensuring that the changes had a nil effect on cost but maximise the performance. The new sections of structure were fully taped and sealed to further ensure they were built using tested methods utilised on previous projects as a benchmark.

The large vaulted section creates both volume and also a temperature control zone allowing the heat to be collected in the upper area and if required the controllable high level rooflights can act as a stack vent. The floor designed to accommodate the underfloor heating system has been designed with the aim of lifetime gain of a concrete floor being utilised as a heat sink, the floor was formed with rigid insulation to the underside of a concrete slab and full contact flooring, the large expanses of glazing both in wall and roof ensure that even in colder seasons the floor maximises the heat gains and further retains overall heat, creating a lower demand on the heating system, releasing over an extended period.

The overall sustainability and lifetime worth of all elements were well considered through the design process, the overall aim to construct and finish the property in long-term durable materials, we also ensured the waste and ultimate landfill costs were reduced by around 90% of what would be expected from a project of this kind.

The original dwelling provided a complex and largely inaccessible property, as you would expect from a dwelling of its age, one key factor though not required by regulations was to create a fully-accessible entrance route to the dwelling, which would let our client’s parents who have increasing mobility issues a simple route to also enjoy the property. This included re-modelling the external garden space creating an interconnecting terrace from the garden entrance allowing for an accessible route to be landscaped into the garden aesthetic. All sliding screens are provided with level access thresholds which remove any structured division between external and internal spaces, this also removed the need to rely on the original stepped entrance doors and formed a clear flow into the main body of the dwelling.

The grange interior 2.jpg The grange exterior.jpg

The project was highly commended in CIAT’s Alan King Award for excellence in architectural technology. The judge’s comments were:

By exceeding the client’s expectations this simple, yet creative, extension is not only considerate to the host structure but has also succeeded in overcoming access constraints for construction, providing an accessible solution for the main dwelling. The entrant clearly understood the judging criteria and addressed each of the categories in a well-considered manner.

This article originally appeared in CIAT’s Architectural Technology Journal, published in Autumn 2018. It was written by Stuart Davidson Architecture.


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