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Roof struts continued

If they are not vertical, struts must be restrained with blocks or chocks.

Diagram showing a vertical strut firmly nailed to a strutting beam or top plate. The nails are 2/75 mm skew nails. Above the strut is an underpurlin with a rafter on top of it. Two nails, one on either side of the underpurlin, attach the strut to the underpurlin. The horizontal distance from the bottom corner of the underpurlin to the edge of the strut is not less than 38 mm on the internal side of the roof and max 12 mm on the external side.



Struts may be perpendicular to the rafters.

Diagram showing a vertical strut set perpendicular to rafters. At its base it is nailed to a horizontal timber with 2/75 mm skew nails. A chock with not less than three nails attaching it to the firm base (strutting beam, top plate, etc) sits behind the strut. Not less than 40 mm of the width of the strut is below the underpurlin, and not less than 25 mm of it is on the other side of the underpurlin for nailing.