Oak in direct contact with Lead

[Lime]

I'd use the polyester for preference.

There's nothing like using traditional materials.

Unfortunately for us today the oak is not seasoned and the lead is as thin as they can get away with, so little is as it was in the past.
In the past they would have made sure that the subsurface was smooth without anything protuding.
Today they can't throw the lead on fast enough.

 

[Flyfisher]

I'd use the polyester for preference.

There's nothing like using traditional materials.

Traditional or appropriate? I wonder how many 'traditional' materials would have been used in the good old days if 'modern' materials had been available back then? (of course, what we now call 'traditional' materials were themselves 'modern' in their own day).

Our history is one of continuous development. I wonder if the traditional timber-framers of old spent their time bemoaning the loss of mud-hut building skills in favour of modern oak framing. :wink:

 

[biffvernon]

Traditional lead - i.e. pre-industrial revolution, tended to be better. It had small amounts of antimony and silver in it that made it more resistant to corrosion. Then they discovered how to refine these more valuable metals out.

If you have any medieval lead....

 

[Alex F]

Here are the effects of a green oak tannin corroding lead - so it's a genunine issue for as long as the oak releases tannins.

 

[biffvernon]

That's a pretty clear illustration.

So either use old oak, from which the mobile tannins have long since been washed out, or slip in a bit of sacrificial lead that you chuck out after a year.

 

[steveb]

Interesting thread, I'd not noticed the phenomena until it was raised on this thread:



These windows have only been in about 6 weeks and yet the staining is very visible below each window where there is lead underneath - not sure if I ought to do anything or not - the oak used should not exactly be green. Hopefully the staining is cosmetic rather than structural

//edit to add missing word in bold !

 

[Keithj]

I went round with a bucket of soapy water and some cloth, and managed to remove all the tannin from the lead. In a couple of places where there was a lot of tannin, I had to rub back till the lead started to look silver in colour.

Then I gave it all a good coat of patination oil, and it's gone a consistent dark grey colour and looks a lot happier.

I suppose, like filling in the gaps between the (gently shrinking) green oak and the lime render, this is an ongoing maintenance item on the house.