Self Build Garden Room – General Design

Strategic Definition

In 2021, I managed to get onto the property ladder and have bought my first home. Something that is tragically becoming more and more difficult for young working people to achieve. This moment in my life has coincided with having also becoming fully qualified as an architect. With the skills that I have obtained in the last 10 years, I now want to apply myself beyond my professional life. Instead of singularly surrendering my personal time and resource to someone else, I would like to use my abilities and my new found time outside of eduction to finally provide a little more comfort in my personal life.

At the back of the property is an old block outbuilding. I considered my options as to what i could do with with the old building for a few months. In the end, the best decision appeared to be removing the existing structure and starting again from scratch largely due to the condition of the building and the poor intital contstruction … and so I began to design…

The outcome of this project is for me to continue learning beyond the boundaries of my own profession and to do this another key element of this project personally is for the entire building to be self built. As a visual and practical learning, i feel this will be invaluable to my continued professional development.

Design Drivers

With such a tight space to build in, the primary driving design concept is one of maximum utility and minimal wastage.

Functionally, the design of the project is simple. The primary space is around 20sqm, which will provide space for a guest/ hobby room looking onto the garden. This has an adjacent bathroom and storage to the back.

To the front of the new building is provision for bike storage next to which is a generous deck which will provide space for summer outdoor relaxation.

Ground Floor Plan

Application of Concept

The design of the building has been set out on a 400mm grid. This is based on the structural spanning capabilities of the timber sections being used; the availability of standardised material and the regulations for building performance.

The timber size that has been selected has been informed by the thickness of insulation needed to maintain the required thermal performance. This has in turn informed the span lengths that set out the building. In order to optimise the grid economically, these span lengths have been considered against the standardized sizes of other materials (OSB, Ply, PIR, plaster etc.) needed for the relevant floor, wall and roof build ups. The chosen 400mm grid ultimately reflects an optimal solution for reducing wastage of these standardised materials and thus creating the most sustainable design solution.

Cross Section through Primary Room


The construction of the project in timber was chosen for several reasons.

Firstly, and foremost, the carbon footprint of this project will be a large driver for the selection of materials and construction methods within the obvious constraints of personal practical ability and capital. For this reason timber has been chosen for it’s more sustainable and affordable attributes and ease of design malleability at smaller scales.

Secondly, as timber itself has good thermal properties, utilising it in construction allows for a reduced wall build up relative to other construction methods such as the more traditional masonry cavity wall construction. This will allow me to design the building to exceed relevant U-value regulations to provide a greater thermal performance without losing huge amounts of plan space on a tight plot. Importantly a greater thermal performance acheives greater long term sustainability goals.

Lastly, I personally have experience in building with timber and because this is my first time aiming to construct a project like this myself, having this knowledge will aid the project towards greater success.

External Timber Wall Construction