Lead Roofing is one of the oldest forms of metal roofing and is particularly prevalent in heritage and ecclesiastical works, but is also well used in general types of roofing such a lead flashing on private homes and also on commercial properties.
Because of its natural properties Lead Roofing is easily formed in to a myriad of shapes and is therefore suitable for creating finite architectural lines and small detail. If installed correctly, lead roofing can last for well over 100 years as can be seen in many of the UKs historical buildings.
Being 100% recyclable lead roofing is an extremely green material choice, as it takes a minimum amount of energy to reform it back into sheeting material for use on roofs etc.
There are 3 types of sheet lead used in lead roofing, the first and most common is milled lead created in sheets of particular thickness. It is used on most projects and can be seen in our projects Lead Roof on Small Rear Extension for Residential House and Lead Roofing on Bay Windows. There is also spun cast lead (which is not used very often) and sand cast lead, being the original way lead was formed into sheet and as a result is usually used on ecclesiastical buildings or for other heritage works.
Lead roofing comes in different codes of thickness, the most common ones used in roofing are between Code 4 and Code 8, with Code 8 being the thickest. It does come in more codes, but they are very rarely used. What codes you use depends on what project you are working on, for instance, roof flashings are normally Code 4 or 5, as the thickness is relevant to the square meters due to expansion and contraction the roof is likely to undergo throughout the year. There are also other contributing factors, for instance, if the roof is going see any foot traffic etc. In essence there are predetermined codes that should be used, which are issued by the governing bodies and which are old and exceptionally well tested.
An instance of where we have used code 5 milled lead is shown in our project where we created a large rear extension on a residential house. In this instance the long box gutter was created with expansion joints rather than the traditional step method, which would not have provided the correct heights and falls to the outlets.
An instance where we created a lead roof on a porch using Code 5 Spun Cast Lead, following their architects instruction is also an example of where we also created a fully bossed central intersection joint detail within the design to create the best possible finish, which was not requested but on consultation with us was agreed to enhance and strengthen the design.
On pitched or flat roofs, normally seen on churches etc., Codes 7 or 8 are usually used as the bays are normally larger pieces and this can be seen in our project on a church roof where, due to the heritage of the building Code 7 Sandcast Lead was used for the main bays of the roof and Code 8 Sandcast Lead in the creation of the parapet box gutters. Another heritage instance is our work on the Duchess of Kent Mausoleum (Frogmore House) where we carried out the necessary restoration, replacing the oval parapet box gutters in Code 7 lead. We were specifically contact for this work because of the challenging of recreating the box gutters by ensuring they were correctly bossed into their oval shape.
In essence the combination of all factors should be taken into account and your roofer will calculate which is required.