Having just laid a new slate roof on my outhouse…

Is there a minimum length for the upstand/drop of a lead flashing? The stone work finshes just 3cm above the top slate, will such a small upstand limit the function of the flashing?

Thanks.

If it is low down I’d not bother with lead as it just gets pinched. Flash banding is a cheap alternative.

Be in this somewhere.

http://www.calderlead.co.uk/wp-content/uploads/2011/07/Calder-Guide-to-Good-Leadwork.pdf

Flashband 🙄

Don’t use flash band its ****!
Pics? As I’m a thick builder and don’t quite understand where on the roof we are?

I suppose a pic would help:

It’s a single sloping/mono pitched roof.

In reality it should fully cover that stone work and dress down the back of it, then I’m presuming the slate under the ones you’ve used for your top course abut the stone? If that’s the case I’d come 100 mm down those too. So looking at it would a 300mm roll do? If not, next size up is 450 which is gonna cost more obviously.

Length of flashing down the slates would depend on the pitch of the roof. That looks pretty shallow from the pic, so prob at least 200mm, but integrated with a capping over the top of the wall head as there’s no way you’d be able to cut in to fix a flashing in the vertical section.
Min of code 4 lead, max 1500mm length between joints would be my guess but it’s years since I knew the lead sheet manual inside out.

Jeff

In reality it should fully cover that stone work and dress down the back of it, then I’m presuming the slate under the ones you’ve used for your top course abut the stone? If that’s the case I’d come 100 mm down those too. So looking at it would a 300mm roll do? If not, next size up is 450 which is gonna cost more obviously.

I’ve got some flat wide stones that need to go on top of the stonework in the picture. They are are 12″ wide and consequently overhang the stonework and slate in the picture by about 3″ each side. If I use lead I was planning on sandwiching the chase strip between the stonework in the picture and the stones that go on top. If that makes sense?

Yes, the top course of slate abuts the stonework.

Oh pet hate slates on side on top row, looks shite. 10+ yrs slating roofs

Another row of blocks on top of that dress the lead down and onto slates and a coping on top of lead

Oh pet hate slates on side on top row, looks shite. 10+ yrs slating roofs.

I didn’t think it looked too bad and thought it might give a bit of extra protection. First attempt at roofing.

Another row of blocks on top of that dress the lead down and onto slates and a coping on top of lead

Ok gotcha, is that simply to increase the amount upstand? Would it be worth putting something under the coping stones to help prevent any water that finds it’s way through the mortar joints?

I didn’t think it looked too bad and thought it might give a bit of extra protection. First attempt at roofing.

Look at the 2 slates that are head to head the join is almost in line with the row below.

Ok gotcha, is that simply to increase the amount upstand? Would it be worth putting something under the coping stones to help prevent any water that finds it’s way through the mortar joints?

Dress the lead in 2 parts from the roof up to the top of the block then a cap sheet that goes over the block over lapping the lead from roof and over the back of block then coping on top. Should be in that PDF I linked to. On phone can do a pic later if wanted.

Look at the 2 slates that are head to head the join is almost in line with the row below.

I see what you mean, point taken.

Dress the lead in 2 parts from the roof up to the top of the block then a cap sheet that goes over the block over lapping the lead from roof and over the back of block then coping on top.

Ok that sounds like a good idea. How much should the two pieces (cap sheet + lead from roof) need to overlap by and how much should it extend down the back of the stonework?

Many thanks.

Edit: A diagram would really help, wouldn’t it? Here we go:

With something like that I would ply deck the stone, and use welted cladding in metre lengths with a secret copper clip in the welts and lead clips on the slate side every 450mm. Code 4 will be ok, and you would need a drip edge on the open side at least 25mm from the stonework with a continuous copper strip and the lead turned over and under the edge, and with such a low pitch I would give the slate side 150mm lap.

EDIT: A bit like this:

Blimey, this could end up costing a few bob.

How much should the two pieces (cap sheet + lead from roof) need to overlap by and how much should it extend down the back of the stonework?

Many thanks.

Edit: A diagram would really help, wouldn’t it? Here we go:

Bump for the evening roofers/builders. Any advice on the overlap of the two sections and how much should be extended down the back of the wall?

Thanks.

What width is the flat section of the block? Might be easier to buy a roll width to fit that. Top of my head I think it was about 50mm min to prevent capillary water ingress. Remember that individual pieces of lead must be no longer than 1.5 metres for expansion/contraction.

It very much appears there is insufficient pitch on the roof and the tile bonds are inadequate. I would remove the whole lot, ply sheet and felt. The plan you have for lead is far more complicated that you think. Poorly installed lead will fail very quickly. Particularly if the roof gets a lot of sun.
There is a code of practice for the installation of lead sheet which is written by the manufacturers and strictly adhered to by LCA members. There’s a wealth of easily available information about building roofs and slating, it’s hard to imagine any of that’s been put to use here.
I know this is harsh but it’s just another DIY bodge as far as I can see.
Also the diagrams above are useless without measurements as there are minimum up stand and lap requirements you won’t be able to achieve unless you build up the top of the wall. All this is moot though, because it would be a waste of money to put lead on what you’ve got and trying to form welted joints over capping stones without lead dressing tools will will extremely difficult.

Mono ridge should do the trick.

If money is an issue, and the width of the wall allows for it you may get away with a mono ridge. However as with everything there are many ways to do it 🙂

EDIT: If you are going for cornice stones on top, a flashing fixed into the top of the wall and then dressed down and onto the slates would be ok. I would also put DPC on top of the wall as well though.

It very much appears there is insufficient pitch on the roof and the tile bonds are inadequate. I would remove the whole lot, ply sheet and felt. The plan you have for lead is far more complicated that you think. Poorly installed lead will fail very quickly. Particularly if the roof gets a lot of sun.
There is a code of practice for the installation of lead sheet which is written by the manufacturers and strictly adhered to by LCA members. There’s a wealth of easily available information about building roofs and slating, it’s hard to imagine any of that’s been put to use here.
I know this is harsh but it’s just another DIY bodge as far as I can see.
Also the diagrams above are useless without measurements as there are minimum up stand and lap requirements you won’t be able to achieve unless you build up the top of the wall. All this is moot though, because it would be a waste of money to put lead on what you’ve got and trying to form welted joints over capping stones without lead dressing tools will will extremely difficult.

I ripped off the old roof last weekend and relaid it, this is the new roof.

🙂

Roofer for 28 yrs here.
That’s a very flat pitch, what’s the headlap?
Flashband?? If you don’t know what you’re talking about put the keyboard away….
Some sort of coping stone over the lead flashing would be your best bet. To lead it as has been described would be expensive and frankly beyond DIY

Roofer for 28 yrs here.
That’s a very flat pitch, what’s the headlap?
Flashband?? If you don’t know what you’re talking about put the keyboard away….
Some sort of coping stone over the lead flashing would be your best bet. To lead it as has been described would be expensive and frankly beyond DIY

Went for 3″ of headlap due to the low pitch. I’ve got coping stones to lay on top of the stonework, however in it’s previous carnation the roof leaked through the mortar joints of the coping stones and into the building. Conseuqently, trying to find a solution that will stop it happening again.

Thanks for the help.

I’ve just completed a similar job on a old stone Pig Sty.

As others have said, the pitch looks a bit shallow, but provided you’ve used a modern membrane beneath (with a generous overlap) and the prevailing wind and rain is with the slope, then you should be OK.

Change the top row of slates and then as Wrighty suggest cover the head wall with lead and then finish with a row of single weathered copings.

You could save a few quid by just tucking the lead under the copings of course.

It’ll be reet
HTH
Marko

As has been said a DPC over the stonework ( and over the lead that will be tucked in under the copings) would be a good idea. A 3″ headlap isn’t going to stop damp penetrating IMO, Capilliary action goes 50mm for starters.
I’m not going to harp on about it but if you do have enough spares slates then replace those top ones 🙂

As has been said a DPC over the stonework ( and over the lead that will be tucked in under the copings) would be a good idea. A 3″ headlap isn’t going to stop damp penetrating IMO, Capilliary action goes 50mm for starters.
I’m not going to harp on about it but if you do have enough spares slates then replace those top ones

Fair enough, I’ll check if I’ve got enough spares. Would the coping stones need to be plaed on a bed of mortar on top of the DPC?

Yes ….and the DPC should not be dry bedded. Go for a DPC that has good adhesion to mortar

***HIJACK***

Any of you roofers live near Macclesfield? If so please come and fix my roof, nobody answers their phone around here and I’m leaking!

Thanks…and sorry OP!