Jonny Briggs designs, manufactures and installs traditional green oak frames, timber structures and joinery components including Oak Framed Buildings Yorkshire. Jonny and his team of craftsmen have completed projects throughout the UK, working for estates, private clients, charities and other organisations .
Projects generally fall into two categories: traditional, hand cut green oak frames and engineered timber components.
Traditional oak frames use recently felled oak (green) which has a very high moisture content, this makes cutting the joints easier as it is softer. As the frame ages and dries out it gets harder, stronger, and the joints become tighter. Joints such as mortice and tenon, lapped and dovetail joints are secured with oak pegs to form solid structural frames, that are sustainable, repairable and have natural beauty and warmth.
More recently, timber has begun to be used in conjunction with steel to create structures that can span larger distances and create uninterrupted open spaces – something that would not be possible using traditional timber framing techniques alone.
Using traditional techniques and sustainable materials, combined with efficient building practices, Jonny Briggs aims to keep traditional skills alive and relevant alongside working in today’s ever changing built environment.
Green Oak Framing
The term green oak framing relates to the technique of using recently felled timber, to create a structural framework that forms the skeleton of traditional buildings, bridges, roof trusses, lanterns, lock gates and other heavy timber structures.
After a tree is felled, it is transported to the sawmill where it is cut to the size and length of timber required. Today a bandsaw is used to cut the timber, but this was done by hand before mechanisation.
The timber is fresh, therefore it has a high moisture content, making it much easier to work with and produce the joints needed to connect the individual timbers into the frames and trusses.
Joints such as mortice and tenon, lap, notch and dovetail are all used to lock the timbers together. In a traditional green oak frame, the structure is designed to be held together using gravity, the weight of each component holding it in place. However, oak pegs or dowels are used to draw the joints tight as this provides additional strength to the oak frame. Braces are typically seen in oak frames as they are used to provide structural stability in the frame.
Oak is a slow growing hardwood, making it the perfect material for the structural components within the green oak frames. Over time, the oak will slowly dry out, and increase in strength. Splits, cracks and shakes will appear, along with some distortion of the timber, however the strength of the timber is not compromised in all but the most extreme cases. Although oak is the most common timber to be used for framing, almost any species of tree can be used as long as it is of good quality, defect and diesis free and the right size.
Once the building is constructed, the oak can be finished in different ways, depending on the desired look. There are three ways to remove any dirt and working marks that may be preset after the construction phase. A planed finish can give a smooth feel and remove any bandsaw marks, where as a hand planed finish will result in an axed or adzed finish, this is more fitting when installing a new timber into an existing oak frame. A sandblasted finish is the quickest way to remove undesirable marks, however it does dull the timber down and removes sharp edges. Sandblasting is usually done when there will be no more water ingress into the building. A hand sanded finish is more selective about what marks are removed and leaves the timber with more character. The cleaning process is often overlooked and can be a costly and time consuming process of the build. The simplest way is to leave the oak to grey naturally over the years, unfortunately there is no way to speed this process up.
Tradition oak framing in the modern world
Although oak frames are synonymous with the past, they are ever present and relevant within the construction and building industry today. When well managed timber is sourced, oak frames provide a sustainable alternative way of building. When built correctly, the durability of oak will ensure that the buildings will last for hundreds of years, not tens.
Green oak frames are often build away from the final location of the structure. This off site manufacture allows a very efficient build process as groundworks and construction of the frame can run simultaneously. Once complete in the workshop, the individual components are loaded on to a lorry and transported to site. With the aid of a crane or suitable lifting device, the green oak frames (depending on size) are erected in a very short space of time, allowing the build to progress at a quicker speed.
There are limitations for the sole use of solid timber beams for construction However with the integration of stainless steel plates, shoes and brackets larger distances can be spanned which meets the requirements for structural calculations.