Cowshed, Koski Manor

Koski Manor produces organically raised Hereford beef cattle which are sold directly to consumers, shops and restaurants. The estate focuses on environmental issues and preserving biodiversity. In 2014, Koski Manor received the WWF award for being the most environmentally friendly farm in Finland.

The farm’s new cowshed is of timber construction. The grounds for the building owner’s choice of timber were its environmentally friendliness and its appearance, coupled with its availability in Finland. The building is fairly sizeable, being nearly 70 metres long and 21 metres deep with a roof ridge almost 10 metres above ground level. An adjoining exercise yard of 600 square metres was built for the animals in conjunction with the cowshed.

The load-bearing structure is a portal frame in LVL (laminated veneer lumber) where the leg of the frame is joined to the top chord by dowelled joints. The leg of the frame is of cross laminated Kerto-Q while the top chord is in Kerto-S where the veneers run in the same direction. The top chord could also have been in laminated timber whereby the need for transverse support would have been reduced as the thickness of the construction increases.

The advantages of a productised timber frame are lightness and speed of erection. Furthermore, it is easy to estimate the quantity of material on the basis of standard solutions. There are no restrictions on openings at each end of the frame. The top chord of the frame is joined to the leg on site according to the frame supplier’s instructions. The unrestricted height inside the frame can be chosen and is usually about 5 metres.

Timber portal frames can be spaced at 10 to 25 metres, but if they are made of laminated timber, the spacing can be as much 40 metres. Three-pin-joint portal frames are mainly used for agricultural livestock sheds, warehouses and machinery sheds. Long-span portal frames are also used for riding schools and bulk storage.

The decisive point in dimensioning a timber frame is the corner. When making laminated arches, the corner should be rounded and usually fairly thick. A corner made of LVL staves with dowelled joints and without the effect of the rounding is stronger, because the unrestricted height of the building is defined according to the inside edge of the structure.

A three-pin-joint frame is joined to the foundations by another joint. In dimensioning the foundations, it is important to take into account the horizontal support at the base of the leg. Consequently, the height of the base of the frame from the foundation must be taken into account when dimensioning the foundations.

Anti-buckling support for the top chord can be provided by board construction on the roof or separate rafters. In a longitudinal direction, the frame of the building is stiffened with gable columns.