Where a vertical surface meets a sloping roof plane, a step flashing is applied. When flashing material is installed in successive courses up a roof slope up against a wall or chimney, the result is called a Step Flashing.
Chimney Lead Work
The joint between the chimney stack and the roof tiles is a common location for leadwork.
The absence of leadwork or leadwork that has failed is a recognised weak point in the design of most roofs, and may cause leaks.
Valley Lead Work
We have been repairing valleys in the Leeds area for over 30 years. Our expertise, great customer services and skilled trademen can get your leaking valley back to how they should be
Run lengths for step flashing should be between 1.2 and 1.5 metres. They should always be in place before the glazing materials are fitted, but may be put before or after the Glazing Bars. This kind of lead flashing should only be used with materials like brick that have regularly spaced horizontal joints and a drainage channel on the glazing bar. The step finish and the lengths of material used in this flashing type are identical to those used in traditional step flashing (i.e. 1.2 to 1.5m). Lead, on the other hand, is not dressed into a drainage channel as step flashing is, but rather over the Wall Bar Top Cap. Lead work may be added before or after the Wall Bar is erected, but it must be dressed down when the glazing material is in place. It's important to wait until the Wall Bar Top Cap has been installed. Step flashing may be used in situations when stones are put in uniform horizontal courses. The preferable way, however, is to use a unique piece of Lead for each step to avoid the stair's uneven appearance. Lead flashing, like the other forms of flashing discussed, may be dressed into the drainage channel or over the wall bar. Each individual flashing must overlap by at least 70 mm. Cutting a groove into the stone and installing the Lead into it is the best way of flashing when using random stonework.
The lead may be poured into a drainage channel or shaped on top of a wall bar, as before. Each run has to be between 1.2 and 1.5 metres long, with a 70-millimeter overlap.
The front lead apron's objective is to seal the chimney's intersection with the roof's completed surface from rain and snow. It doesn't matter whether your final roof is made of tiles or slate; the front apron installation process is the same for both. If you have a brick or stone chimney, you'll need to cut your lead apron into a mortar course before you can install it. This will tell you how high your apron needs to be (often between 50mm and 100mm above the current chimney). Using this metric, you may determine the best way to diverge from the pack and secure the victory. In order for the lead apron to be installed, the mortar course will need to be chased away. A compact angle grinder may be rented with a cutting disc made specifically for slicing through mortar and removing it from mortar courses in a single motion. When installing a lead apron, little folded lead tacks or wedges (which may be carved by hand or purchased already produced) are hammered into the excavated mortar course to temporarily secure the apron in place until it is pointed or bonded securely into place. The lead apron must be reinstalled on both sides of the chimney. When the side stepped lead flashings are placed, they will cover these returns, completing the flashings and ensuring watertightness for the chimney.
Between tiles and anything that causes breaches in the roof's structure, such as chimneys, skylights, vent pipes, and other fixtures, lead soakers are used to ensure that water doesn't leak in. Lead soakers are often used to fill the space between roof tiles and protruding elements like chimneys, skylights, ventilation pipes, and other similar structures. Soakers are installed beneath the surrounding tiles and up against the obstruction to stop water from getting into the attic and perhaps creating mould or leaks. When lead soakers are properly installed into a roof, water will drain off the tiles and into the gutters, protecting the roof from the elements. There is a wide variety of codes for lead soakers that categorise the various thicknesses and, by extension, the functions of the lead. Code 3 lead sheets, which are 1.3mm thick and used for roof soakers, are the industry standard (although code 4 lead sheets can be used which are 1.8mm thick). Thin lead soakers are utilised since using thicker sheets may compromise the roof's structural integrity and the fit under the tiles.
Lead Gutter Back
A chimney back gutter, or any flashing at the point where a protrusion from the roof slope, such a wall or roof window, interrupts the water's path to the gutter, is there to collect and reroute the water so that it does not damage the structure. The amount of water collected is directly proportional to the length of the back gutter and the amount of roof area that drains into the back gutter. Chimney or projection widths may be anything from a few centimetres to many metres. More depth and width will be required in the rear gutter to accommodate the flow of water from the roof, the greater the projection. It's not a good idea to dump a lot of water from a rear gutter onto the roof. It is possible for the roof tile head and side laps as well as the chimney side flashings to be overwhelmed by point loads of water, especially on low-pitched roofs. Internal outlets or open lead gutters may be required to direct the water to the eaves in such cases. Water from the rear gutter should be directed into a hopper rather than onto the tiles in areas where a chimney is located at a gable wall. Alternately, you might build up the lead flashing to form an upstand and divert the water away from the gable.
When a pitched roof is poorly built, the valley is one of the first places water will find its way in. Because water will be channelled towards rather than away from this space, careful planning and execution are required prior to construction.
The mortar bedding is sometimes misunderstood to be there just to keep water out. A valley, however, should function well even without masonry. Some valleys, like those made from double-lapped plain tiles or slate, don't even need mortar.
Single-lap tile valleys are often laid without mortar in Leeds. So, how does one go about making a valley? It's crucial to start with the foundation beneath the valley. In place of just resting on top of the rafters, the valley boards should be positioned flush with their tops. That manner, the tiles aren't required to extend over the valley's rim. As the boarding must be trimmed to fit between the rafters, support timbers must be fastened to the sides of the rafters to ensure the valley boards are set flat. When installing a lead-lined valley, thin plywood linings are placed over the valley boards to keep the valley smooth.