Timber

As with straw, the use of domestic, mostly local, timber in the Footprint means we are using materials that are renewable, some recyclable, and all biodegradable in the future.

© Scott Mackie

They are all from sustainable woodlands, managed for long term-timber production through careful planting, whilst protecting their biodiversity and recreational value in the present.

The roof is of two-layered oak shingles, with a breathable felt membrane. The shingles are from sustainable sources in the south west; even though it requires further transportation ('shingle miles') and thus higher CO₂ emissions, as it has a stronger, straighter, grain than local 'twisty' oak.

It can be split more thinly, so reducing the number of trees that we will need and making the roof a lighter weight for the walls to bear. The roof batons and laths are from local timber.

Lake District green oak will be used for the frame of the building, the doors and windows, and will come from local National Trust sites. From this, the frame will be manufactured by our principal contractor, Lambert and Gill in their workshops in Cumbria. It will be brought in very large sections ready to erect in one delivery, reducing transport impact.

The suspended interior floor and skirtings will be a mix of reclaimed timbers and beech.

The exterior walkway, steps and flooring in the covered activity area will be made from local larch. The rails on the walkway will be made from local oak. As small lengths are needed it means that more of the tree can be used and this will give the balustrade a more organic appearance.

The gutters will also be timber with a system of timber drainpipes.

Foundations

More than 50 million tyres (over 480,000 tonnes) were scrapped in the UK in 2001, 80,000 tonnes of which ended up in landfill.

The foundations in the Footprint will be recycled car and tractor tyres, infilled with rammed, reused subsoil and clay mix into footings.

Straw walls don’t require foundations to be as deep as conventional buildings. Their construction, however, is very labour intensive and will be undertaken as part of the first training course.

Back to top

Glazing

Pilkington K Glass will be used in the windows and glass walls. It has what is called a 'low emissivity' coating on the surface that faces into the air gap of double glazing.

The heat absorbed by the coated glass is inhibited from radiating across the air gap, and then again from the outer pane to the colder outside. Instead the heat is reflected back into the room by the coatings.

Other material facts

• Internally a cob wall (made from a mix of clay and straw), will separate off the main room from the small kitchen and store. This will naturally draw in excess air-borne moisture when levels are high, aiding humidity control.

• There is only the need for a single heat source and a highly efficient stove is planned, taking on-site coppiced timber. By positioning the stove next to the cob wall we will make the most of the 'thermal mass' properties of the cob, which absorbs and releases heat and moisture to maintain a healthy and comfortable environment.

• The stone for the battered base will be a mix of slate reused from the demolition of an on-site garage, and other, unsawn slate/stone. The amount of stone work needed will be reduced by earth banking, and the additional earth and stone needed is from a local source.

• The roof and floor voids will be insulated using sheep’s wool, which is available from a local manufacturer. They use the fleeces from hardier Northern Fell sheep breeds.

• Although the Footprint is organic in feel and style, it will provide for contemporary needs. This includes power for lighting, networked computer use and other technical equipment, and the capacity to be self contained for the provision of tea facilities and associated washing up.

• After much consideration, it was decided the design and materials of the new building will mean that anticipated additional energy needs will be quite low. A separate energy supply, even one from renewable resources, requires materials, manufacture and transport, and is not the most sustainable approach for us at this stage. Instead, the building will be joined to the existing mains supply with a view longer-term to looking at a renewable supply for the whole site, or for the Footprint building, as technology becomes available.

• The running and drinking water needs, are also not expected to be high enough to justify an independent system at present, and will be linked to the mains.