Standard specification and details
Page 15 – Lead ridges, valleys and raking eaves
Standard Specification and Details - Lead Ridges, Valleys and Raking Eaves
Metal Roll Ridges and Hips
Metal roll ridges should be fixed by a qualified leadworker and installed in accordance with Lead Sheet Association guidelines. The slating should be close cut to the wooden roll and head bedded in mortar so as to ensure that the tails fit closely on the course below. An additional mortar bed should then be formed in order that the leadworker may dress the metal without damaging the slates.
Ridge and hip cappings can be made using Code 4, 5 or 6 lead. We would recommend using Code 5 as standard unless otherwise instructed. When using Code 5 lead, each piece of lead used on the ridge should be no longer than 2m and no longer than 1.5m on hips.
Valleys should be formed in lead (be a qualified leadworker) on a board laid down the length of the gutter in accordance with Lead Sheet Association guidelines. The metal should be dressed over the entire valley with a turned-back welt on each edge. The edges of the slates cut on the rake must overhang the welt, leaving a minimum 100mm clear width of the metal valley showing in the centre. Wide slates should be used if necessary so that sufficient width is provided at the tail of each slate. Secret valleys are not recommended because of the difficulty in keeping the drainage channel clear.
A mitred valley is formed by slates close cut and mitred down the line of the valley and laid with metal soakers of sufficient size to lap and bond with the slates of each course and to be nailed at the top edge. Wide slates may be required for dressing, so that sufficient width is provided at the tail of the slates. The slates should be cut in the reverse way to normal dressing so that there is a straight edge on the face of the slate. Mitred valleys are not recommended below 30°.
Slating should always be laid perpendicular to battens, and where an eave is not square the tails of the eave slate and under eave course must be dressed to size on the rake.