Flashing: some sympathetic advice please

[ToughButterCup]

I can hardly believe that I'm writing this post in such a matter of fact mood. I should be furious. But I'm not.  This job needs doing fairly pronto and as usual, I have never done anything like it before. So, please give these images a coat of looking at. Then tell me what you think.

 

There was I, wondering why a bit of water was trickling through my flat roof  - didn't pay it much heed to it  for a while until this recent set of soaking wet, dense, rain-filled Easterly winds. Some of you will know, thats my favourite wind direction here ( Got a strong stomach? Read this).

I strongly suspected that it was my poor rendering skills that allowed water to trickle through into the Durisol, and down into the house. So I toddled up on the flat roof, sucked my teeth, prayed that @nod wouldn't drop by - my workmanship's not that brilliant.  Filled in the odd crater here and there.

 

Lots more to fettle, forgot about it.

Next morning, the hall floor looked like we'd had visit from an incontinent Hefalump. Bugger.

(Not quite a @Russell griffiths 'bugger', but not far off it.)

 

Well now, lets have another little look. Hmm, what about the flashing? 

Heres a piccy the flashing on bottom of the the east facing wall. Part of the capping strip (blue batten) has been removed.

 

(Now, you have to realise, that I know nothing - nothing about flashings, or how to install them. Or best practice, or anything like that.)

 

I bloody well do now.

Never mind who or how it got into that state (but ' Aaahm an it honey, aaaahm an it ') Naughty man. When I see him, I'm going to wee in his fuel tank.

 

My current understanding of the ways of the Flasher is that he shouldn't have installed it like he did.

Because when the water trickles down the superbly efficient parge coat ?, its going to whizz straight past the lead and .... end up on my hall floor.

 

With me so far?   (This is nowhere near as long as a @Nickfromwales post)

Several YooChube videos, and trips to the BM later ... 

 

zooming in a bit ....

 

and then some sealant (CT1)

 

I left half of the wall un-clad. Because its going to widdle down tonight and if I've got the 'fix' wrong, I dont want to have to undo all of my handiwork.

Buckets are already in the correct place for tonight's drips.

 

If the new flashing works, do I back-fill the rest of the groove with mortar (over the CT1)?

 

I'd be so grateful for any advice. Thanks.

Ian

 

[Declan52]

Fill the rest in and make sure you push it in so it completely fills the gap and then leave it smooth and nice and neat. 

It really should have been built in at the start  but you are where you are. The other option would be a grinder and cut a slot into the wall but that won't be easy and will be very messy.

What is your final finish on that section???

[Construction Channel]

I was taught to put the rolls of lead in the groove the other way round, horizontal as such. Then beat them in with the side of a raking chisel so they expand. 

 

Could be wrong but it's how I was taught. 

 

Other lead things would be 6" of lap and max of 1.5m sections but it looks like you have that bit under control

 

Also you can get "lead mastic". dunno if it more flexible or why it would be better than others but they do make one and it's probably cheaper than Ct1 

[ToughButterCup]

8 minutes ago, Construction Channel said:

I was taught to put the rolls of lead in the groove the other way round, horizontal as such. Then beat them in with the side of a raking chisel so they expand. 

[...]

 

Ahhhh, yes, I can see how that would work ...

10 minutes ago, Declan52 said:

[...]

What is your final finish on that section???

 

Pro Clima Solitex Fronta Quattro, then battens then Siberian Larch cladding : it should cover the lead flashing almost completely (all bar 100mm of the lead).

Thinking about it, me telling the roofing membrane (Evalon V) installer that the lead flashing would be almost fully covered ...... was maybe  ermmm, unwise.

.

 

[Declan52]

 I would run a bead of whatever cheap silicone you have knocking about along the bottom edge of the wall to form a temp bellcast to throw the water out from the wall away from the gap till you are ready to finish that front. 

[ProDave]

We seem to do it different up here.  You just fix the flashing to the wall, not in it (might be because I have wood fibre not brick so no easy groove)

 

Then you fit a bell cast drip bead with a built in strip of mesh and render.  The render goes down partly over your flashing, with the mesh to bond to, and terminates in the bell cast bead.

 

It has not leaked yet.

[Ferdinand]

2 minutes ago, ProDave said:

We seem to do it different up here.  You just fix the flashing to the wall, not in it (might be because I have wood fibre not brick so no easy groove)

 

Then you fit a bell cast drip bead with a built in strip of mesh and render.  The render goes down partly over your flashing, with the mesh to bond to, and terminates in the bell cast bead.

 

It has not leaked yet.

 

is that actually that different?

 

You are putting the flashing on before you ave finished the wall, then building the last layer of wall over the top.

 

That is not istm functionally different from the slot and wedge approach.

 

F

[ProDave]

1 minute ago, Ferdinand said:

 

is that actually that different?

 

You are putting the flashing on before you ave finished the wall, then building the last layer of wall over the top.

 

That is not istm functionally different from the slot and wedge approach.

 

F

Except the slot and wedge method will be mostly watertight before the final render.  My method won't be. But this seems the normal method used up here.

[Cpd]

3 hours ago, Construction Channel said:

I was taught to put the rolls of lead in the groove the other way round, horizontal as such. Then beat them in with the side of a raking chisel so they expand. 

This is how I do it as well. 

[Temp]

Think I would turn turn the rolls around, hammer them in well, CT1 bead over the lot eg fill groove including over lead rolls.