Before you start, identify the roof boards from the floor boards. Both of these are 19mm thick but will be different lengths.
Divide the roof boards equally and place ready either side of the cabin. Fit the first board at the front of the roof, lining it up with the edge of the roof beams. The tongue should face the direction of laying and with the decorative angled side down towards the inside of the cabin.
Nail each roof board to each roof beam and to the side wall as you go. Take the next board and make sure the tongue and groove fits together perfectly and nail down. Repeat along the length of the roof, both sides.
When you reach the last board, it may be necessary to saw it to fit. Measure the distance to the end of the roof beam, then saw along the length of the roof board and fix into place.
Note – if you have a cabin with a wide gable, you may find the roof boards are supplied in two lengths. In this case you will need to fix the boards in an alternating pattern. Start with long & short, then short & long and repeat this pattern along the length of the roof.