From Newsgroup: uk.d-i-y

In the process of reroofing an outside toilet roof - mono pitch, using some old, fairly ropey, but still usable slates.

The original roof lapped the lead flashing under the slates. The builder on a job next door says I should lap it over the slates. I see what he means, makes sense, but it won't look as neat and might mean buying some more flashing. And the old roof remained watertight (AFAIK) for the 100-odd years it was sealed that way. Pics here:

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Any comments?!
--
Cheers, Rob
Sheffield, UK
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From Newsgroup: uk.d-i-y

On 10/05/2026 11:49, RJH wrote:

In the process of reroofing an outside toilet roof - mono pitch, using some old, fairly ropey, but still usable slates.

The original roof lapped the lead flashing under the slates. The builder on a job next door says I should lap it over the slates. I see what he means, makes
sense, but it won't look as neat and might mean buying some more flashing. And
the old roof remained watertight (AFAIK) for the 100-odd years it was sealed that way. Pics here:

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Any comments?!

I'm not a builder! The only similar job I attempted was a Victorian
farmhouse slate roof butting up to a brick chimney.

I bought some lead roll (builders merchant and expensive). Folded the
long lap using two lengths of angle iron in a bench vice backed up with
some G cramps. The risers were cut out using tin snips and the tops
folded ready for insertion in the raked out brick courses.

Installation was a pig of a job: having to avoid damaging the old slates
while retaining the lead in the newly cemented brick courses:-(

Perhaps take your roof membrane up behind the lead? Easier with the old waterproof felt!

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From Newsgroup: uk.d-i-y

On 10/05/2026 11:49, RJH wrote:

In the process of reroofing an outside toilet roof - mono pitch, using some old, fairly ropey, but still usable slates.

The original roof lapped the lead flashing under the slates. The builder on a job next door says I should lap it over the slates. I see what he means, makes
sense, but it won't look as neat and might mean buying some more flashing. And
the old roof remained watertight (AFAIK) for the 100-odd years it was sealed that way. Pics here:

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Any comments?!

It looks like your old lead flashing is in vertical strips aligned with
the lower part of each row of slates, but your new battens may not match
the old rows. In which case I don't think it will work - lying underneath
will need trimming and leave gaps, lying on top will not resist driving rain. --- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 11 May 2026 at 09:42:24 BST, Nick Finnigan wrote:

On 10/05/2026 11:49, RJH wrote:

In the process of reroofing an outside toilet roof - mono pitch, using some >> old, fairly ropey, but still usable slates.

The original roof lapped the lead flashing under the slates. The builder on a
job next door says I should lap it over the slates. I see what he means, makes
sense, but it won't look as neat and might mean buying some more flashing. And
the old roof remained watertight (AFAIK) for the 100-odd years it was sealed >> that way. Pics here:

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Any comments?!

It looks like your old lead flashing is in vertical strips aligned with
the lower part of each row of slates,

Yes - 8 strips of lead.

but your new battens may not match

As it happens they do - slates are same size and hole positions as original.

the old rows. In which case I don't think it will work - lying underneath will need trimming and leave gaps, lying on top will not resist driving rain.

I still don't understand how it worked before. Water drips down the vertical brick-inlaid flashing, under the slate, along the folded behind and under strips of lead, then returns back to the wall.

Admittedly that's quite a convoluted route for water to travel, but I'd think some gets through. I've added another pic of a mocked up start on the bottom course (which will be two slates deep).

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Part moral is that I should have paid more attention pulling it apart - but everything turned to dust on contact . . .
--
Cheers, Rob
Sheffield, UK
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From Newsgroup: uk.d-i-y

On 11/05/2026 13:51, RJH wrote:

I still don't understand how it worked before. Water drips down the vertical brick-inlaid flashing, under the slate, along the folded behind and under strips of lead, then returns back to the wall.

I think it should flow down the slope of the roof, but you will get a
wedge of water between the lower half of each tile next to the wall and the lead flashing underneath. With those edge tiles having a slight slope down/away from the wall, as they lean on the edge of the flashing and the underneath tile at the far side. (If you see what I mean).

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 11 May 2026 at 14:31:19 BST, Nick Finnigan wrote:

On 11/05/2026 13:51, RJH wrote:

I still don't understand how it worked before. Water drips down the vertical >> brick-inlaid flashing, under the slate, along the folded behind and under
strips of lead, then returns back to the wall.

I think it should flow down the slope of the roof, but you will get a
wedge of water between the lower half of each tile next to the wall and the lead flashing underneath. With those edge tiles having a slight slope down/away from the wall, as they lean on the edge of the flashing and the underneath tile at the far side. (If you see what I mean).

Ah - good point. Hadn't thought of the slope. Thanks.
--
Cheers, Rob
Sheffield, UK
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

RJH <patchmoney@gmx.com> wrote:

In the process of reroofing an outside toilet roof - mono pitch, using some old, fairly ropey, but still usable slates.

The original roof lapped the lead flashing under the slates. The builder on a job next door says I should lap it over the slates. I see what he means, makes
sense, but it won't look as neat and might mean buying some more flashing. And
the old roof remained watertight (AFAIK) for the 100-odd years it was sealed that way. Pics here:

https://www.icloud.com/sharedalbum/#B1mG3KxPyGUVgZS

Any comments?!

I am no roofing expert but noted whilst out and about this morning on
similar roofs around here, on slates the flashing was tucked under whilst
on concrete tiles particularly the corrugated type it was lapped over.


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From Newsgroup: uk.d-i-y

On Mon, 11 May 2026 14:31:19 +0100, Nick Finnigan wrote:

On 11/05/2026 13:51, RJH wrote:

I still don't understand how it worked before. Water drips down the
vertical brick-inlaid flashing, under the slate, along the folded
behind and under strips of lead, then returns back to the wall.

I think it should flow down the slope of the roof, but you will get a
wedge of water between the lower half of each tile next to the wall and
the lead flashing underneath. With those edge tiles having a slight
slope down/away from the wall, as they lean on the edge of the flashing
and the underneath tile at the far side. (If you see what I mean).

Wondering if the lead laps over the second row of tiles but under the
first row of tiles.

That would still get rain to flow over the tiles, but perhaps hide the end
of the lead flashing.

Cheers



Dave R
--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 10 x64

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