Many properties these days have a lead roof. If you are thinking of fitting a lead roof, it is important that this be properly designed and executed. To ensure this, it is equally necessary to have a good understanding of the material and the skills necessary to work it. There are some common things that can lead to the failure of lead roofing and these should be understood.
Lead is one of the best and most durable roofing covers available. It is commonly used on older building such as churches but is becoming more common on other types of building. A hired contractor or specialist needs to understand potential faults that can occur when fitting a lead roof and how to recognise problems:
• Weaknesses, holes, ripples or splits
• using pieces that are too large for the area covered
• poor fittings and fixings
• poor consideration of temperature and potential for movement
• the use of inappropriate or ill-fitting underlays
Each of these can have an impact on how long the lead roofing will last as well as how effective it will be in its protective function.
One of the main causes of failure in fitting a lead roof is making it too tight or the where the sheet is the incorrect size. Because lead is usually fitted on the outside of buildings it is subject to all kinds of weather conditions and in particular changes in temperature. Lead expands and shrinks in changing temperatures and this should be borne in mind when fitting. A fitting should be the correct size for the area and sufficiently tight to keep it in place but not so tight as to not allow it to move, expand and contract in the changing temperatures.
Other aspects that should be considered when fitting are the weight of a sheet and strong winds. Both of these can cause a sheet to rip away from its fittings or move around excessively. Also, corrosion caused by moisture or dampness underneath the lead sheet can be caused by fitting to a damp surface or warm air escaping from inside the building. This can be eradicated by allowing sufficient ventilation between the lead and the surface. Finally, Lead is a highly valuable and desirable material making it vulnerable to thieves all too ready to steal it. There are some protective measures (ask your contractor) you can take and vigilance is highly recommended.
There is little doubt that lead sheet is a good roofing material – keeping a building dry and protected. But it is highly recommended that you use only trained and qualified tradesmen, skilled in the techniques to fit one.