Lead Welding | A Guide to welding lead
Lead welding is fundamental to the use of rolled lead sheet for roofing applications.
If your roofer cannot weld lead, they will struggle to provide certain details as part of a project.
Our brief guide aims to show you how to weld lead.
Further, we strive to outline the benefits of doing so.
The purpose of lead welding
When carrying out leadwork, the purpose of welding rolled lead sheet is to form details that may otherwise adversely affect the integrity of the material by using traditional bossing methods.
Lead welding allows pieces to be connected without thinning the material.
The practice of welding lead is particularly useful when forming functions and interfaces such as aprons, back gutters, apex interfaces on lead hips and ridges.
Further, welding lead allows custom sections such as hopper heads and chutes for outlets to be formed.
A good Leadworker will always carry welding equipment to undertake their craft.
Moreover, as lead can only be installed in certain lengths, relevant to the code or thickness, lead welding is fundamental when installing expansion joints in gutter linings where a mechanical joint or step is not practical.
Usually, heigh constraints of adjoining roof areas or up stands prevent the formation of steps in gutters and rubber expansion joints are a useful addition to leadwork practices.
Importantly however, expansion joints should always be covered with s separate lead section to mitigate degradation of the rubber in the joint by UV.
Noteworthy, the rubber in an expansion joint, which allows thermal movement to occur, will not last as long as the material around it. Expect therefore for failure of rubber expansion joints to occur sooner than a correctly installed and properly detailed lead gutter lining.
Lead welding rubber expansion joints
Where is expansion joint used?
Expansion joints are used where it is not practical to form a mechanical joint either using a step or timber roll detail.
Commonly, lead expansion joints are used on lead gutter linings.
Such jointing would be used where the base of a gutter exceeds the maximum recommended length of a given code of lead.
For example, code 5 lead could be set in 2000mm lengths before expansion would be required.
Further, expansion joints may be used to split a bay roof where height constraints prevent the use of a wood roll joint or mechanical step.
The use of expansion joints is not best practice. However, it is widely accepted when other methods are not practical.
The ability to weld lead, when using expansion joints is the only method of forming a watertight joint.
Lead welding outlets
The use of welding methods is useful when forming outlets and spitters to ensure effective discharge of rainwater from lead gutters on certain types of buildings.
The example below depicts a fully welded lead chute with overflow weir and outlet spigot on a recent Church roof project.
Welding Lead | Further details
Welding can be used to create a range of details which are fundamental to proper and compliant leadwork.
At The Lead Lads, we rely upon welding lead sheet to execute much of the work that we do.
Importantly, lead welding is often unique to an individual, a sort of signature.
Each leadwork operative will have a slightly different style which will be shown by the weld.
Importantly, the overall aim is to form strong and watertight joints when bonding rolled lead sheet by lead welding.
Note the differences between two Leadwork styles below…
Lead Welding | The Lead Lads
Interestingly, each Leadworker who engages in lead welding will develop their own unique style, sort of a signature.
It is the case that no two welds are the same. However, the nature of each weld will be similar.
Patters will emerge and may depend upon whether the lead work specialist is right or left handed.
Further, how they hold and move their welding torch will also impact the style of the weld.
Importantly, however, you should always use lead sticks when welding.
Essentially, to create a joint in lead using a weld, you are adding more molten material on top of a joint.
However, a pre weld is required to bond the lead sections together before adding the top weld.
