Oxfordshire Woodland Group

The cruck barn plan profile was laid out on the framing floor using orange builders line stretched between nails driven in to the plywood floor at each corner of the building.

The long sills were then raised on blocking to check and make sure that there were no screws holding down the plywood underneath the sills and to enable jacking same (and later on the whole frame) using a farmer's jack.

The south sill was rotated to employ the best straight side facing outwards however it was noted that both sills bow outwards slightly (1.5 inches each). The south long sill also dips downwards over its last 8 ft.

After setting both long sills a laser spot level was used to establish the top surface height of same. This revealed that the elevations where the cruck feet will sit vary from 0.5 - 3.5 inches and so further final levelling using shims will be required.

The preliminary attempts to layout and then line & level the irregular shaped sills have identified that a series of cummulative errors are probably at work. The long sills are very heavy and so attempts to repeatedly move these to optimise the layout levels are quite challenging requiring jacking and shimming and so thoughts are turning to commissioning a GeoSLAM ZEB-REVO CAD survey as supplied and performed by Survey Equipment of the sills. This type of survey only takes minutes to identify millions of data points enabling the subsequent production of a 3D AutoCAD model file that can be interrogated and manipulated on screen to help optimise and minimise level differences at the 6 major points where the cross sills meet the long sills. These 6 points are where the cruck blade feet will sit and so differences in level at these positions will need to be reflected in the cruck leg lengths or alternatively by cutting housing in the top surface of the sills to accept the cruck feet.

Though these differences in section and form might appear to make life somewhat difficult it is worth reflecting on the aesthetic and environmental value of using bent timber.

Ken Hume OWG