How to correctly store Rolled Sheet Lead - Ideally:

• The environment is to be clean and dry.

• Stored on a raised pallet, eliminating contact with the ground.

• Leave in its packaging, however, ensure to open up the packing ends to allow airflow and to avoid condensation forming on the rolls.

• Stacking pallets will result in the deformation of the rolls below.

Alternatively (stored standing upright):

• The environment is to be clean and dry.

• Check regularly for signs of water ingress

What is it? Lead Carbonate

Cause? Environment damp when installed. Material became wet when transported / wet when installing.

Treatment:: Small areas can be removed using harsh rubbing with a dry cloth. Larger areas of staining will be removed with a mild acid solution – widely available. More server staining, use a fine wire wool ensuring to rub in the direction of the panel and insure all panels are worked in the same way.

Important: Applying patination oil will reveal unsightly rubbing swirls if all panels aren't worked in the same direction).

Appearance: Thick, flaking white residue to the surface of the lead.

What is it? Lead Carbonate.

Cause? Usually seen under windows flashings as a reaction to the incorrect use of acid-curing silicon sealant.

Treatment: If left untreated, the Lead may fail within 6 months of installation. Immediately remove the sealant; clean the lead, and apply patination oil. Reseal with a lead neutral curing mastic.

Appearance: Brown stains on the surface of the lead.

What is it? Lead Oxide

Cause? Apparent at point of install. Usually as a result of the Lead rolls being stored in damp conditions; capillary action has drawn moisture into the roll which has distilled to form Lead Oxide.

Treatment: Light staining can be wiped (treated as above). Specially developed lead cleaners are available.

Severe staining will eat into the surface of the lead and may need removing with a suitable abrasive wool or brush.

Appearance: Brown stains on the surface of the lead.

What is it? Bituminous run off

Cause? Thought to be result of newly applied patination oil reacting with the underside of the continuously bonded bituminous product. The Lead has been affected by and/or contaminated by another product or materials – specifically but note exclusively; chemical attack: i.e. acid, bituminous or underside corrosion attack.

Treatment: This is not a lead related issue and in most cases the staining is aesthetic only. Unfortunately, how to remedy the problem depends upon the response from each individual bituminous product manufacturer as their products may have differing chemical compositions.

Appearance: Brown/red, irregular staining forms post installation.

What is it? Lead Dioxide thought to be caused be Nitrogen Oxide (NOx) emissions.

Cause? The reason for the staining is not entirely understood. There is a consensus that the stain may be caused, by NOx emissions from aviation fuel as staining has been found under flight paths. This theory is yet to be proven.

Treatment: The stain, a brown/red mark on the surface of the sheet can appear at irregular intervals and without any noticeable or apparent cause. No detrimental effect has been recorder to the performance of the lead sheet.

Further reading