Roof Rafter Spread

This is referred to as roof spread.

Roof rafter spread.

Split ridge board causing rafter instability and subsequent applied horizontal thrust to the wall plates. Roof spread occurs when there is a failure to adequately support the main rafters of the roof so as to prevent them spreading further open in a scissor type action. N modern cut timber roofs pre 1970 constructed on site this force is normally resisted by joining the bottom of each pair of rafters see fig. If looking for the obvious and common cause of roof spread then this particular issue could so easily have been missed especially when limited to a head and shoulders inspection from the loft hatch.

This ties them together and prevents any outward movement. It also leaves a void the loft which can be used for storage or the placing of water tanks etc. Roof spread can be dangerous for a house and very damaging for a roof. Please follow and recommend our blog page.

Roof spread occurs when the principal rafters of the roof are not adequately supported causing them to open in a scissor like pattern. Therefore the first signs of roof spread are often cracking bulging or leaning at the head of the masonry causing bowed walls. Roof rafter decking sagging. Since the rafters are fixed to timber wall plates sitting on the head of the masonry wall then roof spread pushed out those wall plates in the process pushing out the masonry below.

Roof spread affects a roof that begins to move after it is installed. 2 with ceiling joists. This article describes a diy repair project using a site built spreader to straighten sagged roof rafters and decking. Factors that cause the situation include bad construction improper materials and water and rot problems.