Lead Flat Roof Detail

At vanguard roofing we can install rolled lead sheet roof coverings for bays and panels.

Lead flat roof detail.

Our basic fitting guides are designed to assist installing rolled lead sheet in a range of roofing applications including flashings valleys gutters and flat roofing. Lead is used to make flashings soakers and trays for example around chimneys and dormers. On a low pitch roof where the lead isn t free to move it is more likely to buckle on expansion or stretch as it contracts. Used to join lead together into smaller pieces reduce expansion and contraction issues create up stands and troughs provide.

A new lead bay fitted in a simple one piece bay like this one the lead is nailed into the upstand underneath the guttering the drip is then beaten nice and tight over the edge of the roof and trimmed to about 50mm. For roof detail the gauge of lead to be used will be dependant upon the application. Horizontal flashings should provide weathering to a minimum of 75mm above the intersection with the roof. However it is important to follow the basic principles of sizing and fixings as indicated in the rolled lead sheet manual to reduce the effects of fatigue cracking or creep.

It is shaped to prevent wind lift. Where a pitched roof abuts the wall at an angle. Wood core roll as used on ridges hips and flat roofing wood core roll is to be used to allow for the expansion and contraction in lead sheet and flashing. For sadles near ridge detail or for valley construction at a roof intersection where one pitch joins another.

Investigative work carried out on warm roofs covered in lead has shown that in rare instances moisture can also be introduced by the development of sub atmospheric pressure in the roof space. When a hot roof surface is suddenly cooled by rain the pressure in the area between the vapour barrier and roof covering can fall below atmospheric pressure. Others would treat even steeper pitches as flat roofs. When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off.

Wood core roll is used for joining bays of lead roofing also on steeply pitched roofs and lead cladding where a bold joint appearance is preferred. Where a flat or pitched roof over an enclosed area abuts a wall or a balcony abuts a wall cavity trays should be linked to the flashing to prevent water penetrating into an enclosed area. The definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal however some in the industry would consider up to 15 o as their definition of a flat roof. Lead sheet is a soft and malleable metal which means it s an excellent roofing material because it can be formed and shaped to suit any detail.

Note no nails in the edge.