lead failing?

[ekon]

NW facing roof-line..2 pitches because of extension to original outer wall in room below (ground floor)... job done c.1990. 20"x10" slates and roofing membrane underneath both sets of slates. Lead sheeting used where the pitch of the roof alters (see photo)..underlying the 2 rows of slates.

We had no problems for well over 20 years..but in the past couple of Winters have had some water ingress into the room below..mainly just staining plasterboard ceiling but last year dripping through.

Really heavy Summer rain ("monsoonal" type associated with warm conditions..you know) does not cause the problem..guess it doesn't last long enough. It happens in Winter when we get days on end of heavy rain..maybe when strong winds really drive the rain too...that can't help. So I don't think its broken slates that just "let it through"..it seems to be cumulative...the slates seem ok.

The lead sheeting seems to be only code 3 (I still have a small amount that was left over ..only just over a millimetre thick) and it's laid in lengths well exceeding guidelines (1.5m max. length per section for code4?) - in our case there are 2 lengths of 3m and one of 2.5 m! (the overlaps though seem ok in terms of length).

Could the lead have failed over time due to the over-long lengths used?..especially given its probably only Code3?

Is there a realistic alternative to lead for this job? If not..would Code4 suffice..or should I go for Code 5? Any other tips gratefully received.
thanks for reading

Untitled

• ekon
• 3 Aug 2014
• 1

 

[Xenon]

I'd clean the crap off first, may be getting some capillary.

 

[ekon]

>Xenon..thanks..it's a fair point & I will do.
Not trying to be clever but it's an annual job here as it goes..Autumn usually..a right pain as no sooner have you done it it starts building again. Problem is the stuff you can't see! We had a 15 ft. bough fall on another section of the roof (almost 70 slates replaced) this last Winter and there were a lot of pine needles under the slates that had built up over the last 25 years behind each of the roofing battens on top of the membrane (which luckily was not damaged and kept the water out of the house..only a few drops got through some small minor puncture holes).

The trees (lots) that cause(d) that mess are almost all taken down now..the rest (eight) go later this Summer. Yes..I'm sure the roof would have been better without them...should have had 'em down years ago in hindsight.

Capillary action could be a factor as you say..however, I am still of the opinion that the lead-work is dodgy and has maybe failed..given the length of the sections employed and the code (thickness) of lead sheeting used. Anyone with experience of lead-work specifically offer any comment? thanks

 

[ree]

Agree with the above.

You will have to start the slow process of cleaning out the pine needles, twig debris and moss from the slates.

Perhaps cut back any remaining overhanging branches?

Work should be done off a roof ladder or you will end up with cracked slates.

Slowly water test from low to high (with an inside observer) after cleaning.

Code 4 in 2m lengths will be fine but first examine, by lifting the lead, to see if there's any damp residue under the flashing. And check for splits.

A gable/ verge pic might help here, given the shallow pitch for the flashing?

 

[Nige F]

[4quote="ekon";p="316600"]
The lead sheeting seems to be only code 3

][/quote]. code 3 is 3 pounds weight per square foot - so you could weigh a piece and check it