What Is Patination Oil and Why Use It on Lead?

Freshly cut lead has a shiny, silver face. Within days of exposure to air and damp it starts to react. A dull grey skin forms in time, and that skin is the lead's own protection. During the early weeks, though, the surface can throw off a soft, white powder.

What is the white powder?

It is a lead carbonate, a salt formed when the metal meets moisture and carbon dioxide in the air. It is not dirt, and it does not mean the lead is failing. Rain carries it off the sheet and onto whatever sits below. On a dark slate roof or a pale render the streaks show clearly, and they can be stubborn once they have dried into the surface.

This is the problem the oil exists to solve. It does not stop the lead weathering, because the grey skin forms underneath it as normal. It simply controls how the early reaction behaves while the sheet is still new. Our page on white staining under lead explains what to do when the marks have already appeared.

A patination oil is a thin film. It sits on the face of the lead and keeps rain and the air from reacting with bare metal too quickly or unevenly. With the film in place, the surface turns the same soft grey all over instead of patchy bright and dark areas.

Where does the oil go?

It goes on the exposed face of the lead once the flashing, soaker or valley is laid and dressed. A roofer wipes or brushes it on a dry day, covering the visible surface and the cut edges, and takes care not to leave pools in joints. It is a finishing job done at the end, and it takes minutes beside the hours spent on fitting the lead.

Is it worth the extra step?

On a prominent chimney, a front-elevation abutment or any lead above light-coloured stone, brick or render, yes. The marks it prevents are the kind a customer notices from the pavement a month after we have left. On lead tucked out of sight over a rear dormer, the case is weaker, though a coat does no harm. On an older stone house, an even grey finish also keeps the lead looking as it should against the walls.

An oil gives a protective surface. It cannot improve a badly made flashing, and it should never be sold as if it could.

Does it make lead last longer?

Not in itself. Lead can last for over 80 years on a sound installation, and that comes from the weight of the sheet, the length of each piece, the fixing and the detail at the wall, not from a coat of oil. A cracked or lifted flashing stays cracked or lifted whether it has been oiled or not. If you want to know why lead splits, read our answer on why lead flashing cracks.

The oil also wears. It is a surface finish that weathers away over time, which is expected and does no harm because by then the lead has built its own patina. Reapplying it to old lead that has long since turned grey makes little difference, and it is not a routine maintenance job.

It is not a sealant either. It does not close a joint or fill a gap, and it must never be used as a substitute for a properly dressed edge.

Because the oil is cheap and quick, it is easy to leave out when the day is running short. That is false economy if the wall below is pale stone or the lead is going on a chimney the neighbours can see.

Should I ask for it in the quote?

Yes, if the lead is new and visible. The question to put is simple: will the new lead be oiled before the scaffold comes down? A roofer who has done this before will give you a plain answer. Remember that lead can only be oiled once it is dry, so the job may wait for a fine spell.

New lead also needs correct fixing and sensible lengths to do its job for a long time, and our types of lead flashing page shows how each position is built. For the full range of work, see lead work. We survey first and show you photos of the roof, and the oiling is agreed with you before the scaffold comes down.