When we first met with Adrian and Katrin at Lavender Banks, they knew they wanted an oak frame extension but with a modern, clean feel. With this in mind, we worked closely alongside the architect to create a design that would achieve the desired look.
During this design stage, we started to notice a few issues. The large sliding doors wouldn’t work with the movement of the green oak frame; therefore, we needed to create a new system to allow the oak to move and settle whilst still supporting the doors. Working alongside the architect and engineer, we came up with a design whereby we used air-dried oak for parts of the frame, incorporated with some steel to help support the doors.
Adrian was very specific that he wanted the extension to be as eco-friendly as possible. Working with the architect, we created a new slab foundation design. In this design we put insulation under the slab foundations to allow the slab itself to work as a heat storage. Alongside this we increased the amount of insulation in the walls and roof space to trap as much heat as possible whilst allowing for air flow to avoid issues such as dampness and condensation build up.
Once the design was completed work could start on the foundations for the building and we could start the process of building the frame in our workshop. This process all starts with more detailed drawings showing precise measurements and joint placements for the framers to work from. The finer details will also highlight any issues that may arise during the framing process (clashing of tenons for example)
The timber arrived from our supplier and once checked for defects work could start in earnest on building the oak frame. Our team of specialist green oak timber framers would lay out the timber in the workshop, adding datum lines, marking and cutting joints to very precise measurements, ensuring that everything fits together perfectly before being transported to site.
Adrian and Katrin visited the workshop on several occasions to see the process of their dream coming together. They were able to meet the team and ask any questions with regards to the work that was being carried out. Adrian had a particular interest as he enjoyed carpentry as a hobby and was fascinated by the work the team were doing.
The insulated panels that were to make up the walls of the building were also constructed in the workshop. Comprising of 4×2 structural grade timber, inset with 100mm PIR insulation and lined with 12mm OSB sheet material on the outside these panels add warmth and structural integrity to the oak frame.
After several weeks of sawing, drilling, planing and chiseling the frame was completed. Now it was time for the raising of the frame. This is probably the most exciting time of the whole process, not only for Adrian and Katrin but also for our team of framers who can see all their hard work coming to fruition.
The frame was transported to site and offloaded at the rear of the building where a crane was waiting to assist in the frame raising. Adrian and Katrin watched on in anticipation as the first posts were secured in place. Tie beams and braces were next, and the building was starting to take shape. As the day progressed the weather turned against us and the wind started to pick up. A site meeting was held to discuss the risks involved and it was decided that we were safe to proceed but all were to be extra vigilant during this difficult process. By 5 o’clock on day 1 the basis of the frame was up with purlins and a ridge in place and the building secured.
Katrin and Adrian were amazed at the speed in which their extension had already started to take shape and after months of hard work and discussions, pawing over drawings and designs they could at last see the beauty of an oak frame, all be it in its naked form.
Next the insulated panels were secured in place, and the building was made watertight and weather proof, now the frame could be cleaned.
On this occasion, Katrin and Adrian were looking for a clean modern feel to their extension which required the frame to be sandblasted. Sandblasting (firing kiln dried sand at high pressure) an oak frame will remove any surface marks and gives the oak a very tactile feeling, revealing the woods natural grain and colour. We always use someone with experience in sandblasting oak as being too aggressive can produce a negative effect causing permanent and unrecoverable damage to the surface.
It was time for us to move on to the exterior of the building, allowing access for other trades, such as electricians and plumbers to carry on working the interior.
The rear of the building was to be finished with cladding. We offer a number of choices such as Shiplap (overlaying), Tongue and Groove (interlocking boards) and the more traditional option of Feather Edge. The most common timber used in the UK includes Western Red Cedar, Larch and Oak. On this occasion Katrin and Adrian opted for Feather edged Larch.
The first stage was to cover the exterior with a breathable membrane. This membrane acts as a water-resistant barrier that keeps liquid water out but allows water vapor from the inside of the building to escape. This is crucial in maintaining indoor air quality and the structural integrity of the building.
We then fix vertical timber battens to the wall before attaching the cladding, creating an air gap which allows moisture to escape and prevents fungal growth. This layer of trapped air also adds durability to the building and improves the overall insulation. Stop ends are attached to the corners of the building and trims added to window and door frames before the cladding is fixed. These are to protect, finish and seal the exposed edges of the cladding and provide a seamless transition at the end and corners of the building.
That was pretty much the end of our involvement in this building, however Adrian and Katrin still had plenty of work to do. The large sliding doors were installed, walls plastered, and the final finishing stage of the project completed. We added coverboards and other various finishings to help finalize, what we think is a beautiful extension to a beautiful family home.
