Lead Valley Repairs
On this project in Skipton, Yorkshire we were asked to make Lead Valley Repairs, due to water ingress into the bedroom below. One of our specialist team members diagnosed the problem, as a split in the Lead Valley.
Our Roofing team attended the property and discovered that the Lead Valley had been laid without a movement joint. This resulted in the lead valley splitting due to thermal movement.
Lead Movement Joints
A movement joint is designed to allow the lead to contract and expand in different weather conditions. The joint helps to reduce stress on the material and prolong the leads life span.
Our roofers stripped back the existing Stone Roofing Slates from around the roof valley. The stone slate were stacked on an access scaffold. Some of the slates had been nailed to the battens, this made it difficult to strip. UK Restorations Services prefer to use aluminium pegs for stone slates. They have a longer lifespan over traditional nails and makes replacing slates easier. When our roofing contractors removed some of the lower stone slates, the length of the slates were over 1 metre long.
The existing lead valley had been laid in one piece, so there was no way for the lead to thermally move (contract & expand). Our roofers believe the leadwork was around 20 years old, so it has done well to last that long. Once the split lead had been removed from the roof valley, our roofers inspected the valley boards below. Despite the water ingress caused by the split lead, the valley boards were in good condition with no signs of rot. The timber valley boards were left to dry out, before a membrane was laid onto them. The membrane creates a smooth surface for the lead work to move on during thermal expansion & contraction.
Choosing the correct Lead
Lead comes in various thicknesses and weight per square meter, these are referred to as codes. Code 3 lead is the thinnest and is often used for Soakers, whilst code 8 lead is the thickest and most commonly used for Flat roofs, Dormers & Canopies. A higher code of lead is often used on building in remote area that are more exposed to weather elements.
Lead Valley Repairs on stone slate roofs are best done in code 5 or 6 lead as most buildings with stone slate roofs are in exposed areas. For the specific prject we used code 6 lead to line the valley. We also repaired the leadwork on the opposite lead valley. Both of the lead valley had splits in them. Our roofers took just 5 days to repair both lead valleys.
Our roofers then laid the stone slates back into there original position. A few new slates need to be sourced as they had split.