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Stepped cover flashing geometry, different for a 30 degree pitch?


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It seems that before I can lay any slates I need to rout out the mortar for the 25mm inserts of the lead stepped flashing. All examples state this should be 65mm above the slate height before the steps are cut out and following on from this a 150mm wide roll of code-4 lead will suffice.

 

However I cannot picture whether a more shallow roof pitch from the average 40 degree pitch will need wider or thinner lead roll. As a follow-on consequence of this I am unsure how high I should start griding out the mortar in the brickwork to accommodate stepped flashing inserts.

 

Think I will have to mock up a 2m run of stepped flashing with cardboard. 

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65mm is the minimum up-stand for any lead, you can do more if you want to.

 

150mm wide code 4 is still fine as long as you stick to the 1.5m max lengths.

Make sure your soakers are code 3 so it doesn't cause any obvious uplift under your slates.

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+1

 

The soakers do all the work. The stepped flashing really just stops water getting behind the upstand of the soaker. 

 

So form a soaker with its upstand and put it in place temporarily at several positions up and down the roof and mark a line on the wall with chalk. Then you can see which mortar lines can be cut without going into the area where soaker upstand will be and mark them

 

Some typical dimensions on righthand side below..  85+65 = 150mm

 

 

image.png.e77ea7563578d4649a075165ecee2fde.png

 

 

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5 hours ago, makie said:

Make sure your soakers are code 3 so it doesn't cause any obvious uplift under your slates.

 

 

I noticed this uplift issue after making a couple of code-4 soakers. Think I will reassign the existing 210mm code-4 roll to the stepped flashing, buy a roll of code-3 and start again with the soakers. There was me thinking more expensive code-4 = better soakers.

 

5 hours ago, makie said:

150mm wide code 4 is still fine as long as you stick to the 1.5m max lengths.
 

 

Fascia to ridge is just 2m which means my sections should be about 1.2 allowing for an overlap and some over reach behind the gutter end.

 

5 hours ago, makie said:

65mm is the minimum up-stand for any lead, you can do more if you want to.

 

 

When I switched to mortar raking this afternoon I had make a cardboard stepped flashing template to visualize where mortar had to be removed. Prior to any slating this required some numeric juggling to allow for the extra height of two slates plus a soaker.

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