Formula for length of lead roll for stepped flashing.

[epsilonGreedy]

I am looking at a roofing quote and I am trying to work out the labour element once material costs have been deducted.

 

It is a small job just 19 m2 and I will be supplying the natural slates and ridges. I suspect the largest material cost within their quote is lead flashing roll.

 

How much lead roll is needed for a 30 degree pitched roof abutment that is 4150mm long i.e. 2m up one slope to the ridge and another 2m down the other side.

 

My working assumption is the flashing will be a standard design using an angled soaker for each 500 x 250 tile all capped off with a staggered length of flashing tucked into regular facing bricks.

 

If my description of the flashing design is not clear I will be following this video 

 

 

[PeterW]

If you’re using slates why not use a hidden gutter as it reduces the amount of lead by about 30% and also looks nicer as slates will kick with lead soakers under them. 
 

Using soakers and steps you’ll need about 5m of 250mm and similar of 200mm. Budget a 6m roll of each. 

 

[Mr Punter]

The zinc and the aluminium soakers seem to be OK.  Cost about £1 each.  You need to be a bit careful about mixing metals re electrolysis.

[Gus Potter]

39 minutes ago, PeterW said:

If you’re using slates why not use a hidden gutter as it reduces the amount of lead by about 30% and also looks nicer as slates will kick with lead soakers under them. 
 

Using soakers and steps you’ll need about 5m of 250mm and similar of 200mm. Budget a 6m roll of each. 

 

Good points Peter et al.

 

You may wonder how he works this out!  If you search the net for "guide to good lead work" then you will find extra advise and tips on what to do (laps etc) and what not. Make sure you read about patination oil as you don't want a nasty big lead oxcide (white) stain down the roof after you have done all the hard bit.

 

[PeterW]

10 hours ago, Gus Potter said:

If you search the net for "guide to good lead work" then you will find extra advise and tips on what to do (laps etc) and what not

The lead bible is here 

[epsilonGreedy]

11 hours ago, PeterW said:

If you’re using slates why not use a hidden gutter as it reduces the amount of lead by about 30% and also looks nicer as slates will kick with lead soakers under them. 

 

 

I had bumped into hidden gutters in my research but got the impression they were mostly used for abutments where the cover is a manufactured tile and it would be difficult to shape the soaker around the tile.

 

I shall go for a walk around the village and look for the lead soaker tell-tale kick you warn about. Thanks I had not considered this point. However looking at the following diagram, would the secret gutter not kick the slates as well?

 

[epsilonGreedy]

11 hours ago, Gus Potter said:

Make sure you read about patination oil as you don't want a nasty big lead oxcide (white) stain down the roof after you have done all the hard bit.

 

 

There is an example of this near me on a 10 month old roof, the lead oxide has run down a gully on a pantile roof and it looks like 4m of white alarm cable has been left on the roof. While reading up on the subject of patination oil one tip I got was to lift the flashing and oil the inside lip.

[PeterW]

34 minutes ago, epsilonGreedy said:

 

I had bumped into hidden gutters in my research but got the impression they were mostly used for abutments where the cover is a manufactured tile and it would be difficult to shape the soaker around the tile.

 

I shall go for a walk around the village and look for the lead soaker tell-tale kick you warn about. Thanks I had not considered this point. However looking at the following diagram, would the secret gutter not kick the slates as well?

 

Thats a plastic hidden gutter. I’m talking about one done properly in lead. Then you don’t need the flashing over the top. 
 

Like everything, done properly they look fantastic, done wrong they are awful.