PITCHED VALLEY GUTTERS

Code 4 is the minimum thickness to use. To provide a weathering life equal to that of the tiles or slates which overlap the lead on each side, pitched valley linings should be fixed in lengths not exceeding 1.5m. Each piece should be fixed across the top with two rows of copper clout nails. Diagram 10

Valley boards should be level with the tops of the rafters so that tiling battens and tilting fillets are the same height. With traditional roofing the valley boards can be recessed into the rafters. However when roof trusses are used the boards must be cut to fit between the rafters. For pitches of 30° and above, the lap between pieces should be 150mm, increasing to 220mm for a pitch of 20°.

SOME important points…

Don’t nail the lead down the sides as this will restrict free thermal movement and result in failure.

Don’t lay sarking felt under the lead. It will cause the lead to stick to the boards in hot weather.

Use copper or stainless steel clout nails to fix the lead – NOT galvanised steel or aluminium.

The single welts at the edges of the linings are necessary to provide a weather check.

When bedding tiles down the valley do not mortar directly onto the lead. – use a separator e.g. cement fibre sheet – see diagram10.

LEAD RIDGES AND HIPS  

Lead ridges and hips are normally used on slated roofs. A wood roll is required and should be fixed as shown in Diagram 11.

The flashings must extend over the slates or tiles a minimum of 150mm on each side.

A practical method of fitting the flashings that will avoid thinning at the corners is to form the lead into a trough as in Diagram 11. The lead is pressed down over the roll to fit closely to both the roll and the roof surfaces. Use a minimum of Code 4 lead sheet for both ridge and hip flashings and again, the maximum length of each piece should not exceed 1.5m.  

Laps between pieces should not be less than 150mm – see Diagram 12a – although for pitches below 30° the hip laps should be increased to 200mm.

It is important to fix the top of each piece of hip flashing to the wood roll with copper clout nails – see Diagram 12c. Nails are not required at the ridge laps.

Clip fixings along the sides of the flashings are absolutely essential and should be spaced to suit the

Exposure of the building. Note the extra fixings in the clips shown on both the ridge and hip laps – see Diagram 12. In all but very sheltered

Exposures these fixings will be required.

At the junction between ridge and hip flashings – Diagram12b – and also where the roll terminates at the hip end, the lead will need to be dressed to fit or alternatively can be formed by leadwelding or soldering.