There are a number of different insulation options and many different materials available. You will need to decide what level of insulation you would like or need to pass Building Regulations.
If you are having a small unheated workshop or summerhouse in your garden then you may just want some insulation to take the chill off. The most cost effective way of doing this is with a quilt insulation, usually 100mm thick, which can be put between the rafters and studwork. You will need to make sure you put a breathable membrane on both the roof and the walls.
As soon as you start attaching to your existing property or want to heat your building then you need to up the insulation values. Building Regulations stipulate minimum values for floors, walls and roofs but you may want to improve on these values to help reduce future heating and energy costs. You also need to take into account things like heat loss, thermal bridging and condensation risk analysis. These things are especially important when using a green oak frame because the oak will shrink over time and you need to minimise the effect of the shrinkage.
One easy way of dealing with this is by using Structural Insulated Panels (SIPs) which are positioned on the outside of the oak frame. This also means you see more oak timber inside. There is also the option of having some insulation between the oak frame and a layer outside but since no two jobs are exactly the same we will work out the best way to insulate your frame given the parameters of the building itself and the values you need/want to achieve with regard to thermal, sound and fire performance.
If you would like more details on this or to talk through a project you have then please e-mail us at Insulation@ehbp.com and we will be happy to help you find the right solution for your project.