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Lead work against parapet wall into box gutter - umbrella or blanket?

My main contractor on an extension has done some lead work on a parapet wall into box guttering, however I know this has not been done by a roofer and I am dubious that the lead has been correctly laid. From the top of the parapet wall there is a two brick drop to a small mortar step about 50mm wide and then a fall into an aluminium box gutter. The lead has been laid in an umbrella fashion i.e. it is secured to the top of the parapet wall, ready for coping, then there is a void between the wall/mortar step before the lead falls into the aluminium box gutter. I would have expected this to have been laid more like a blanket, tight to the parapet wall side and the mortar step. It has also not been laid in sections but as a long strip e.g. 5m long. I would be grateful if someone could advise on whether this is in line with good practice or whether I should go back to the main contractor and have a word. Thanks!

4 Answers from MyBuilder Roofers

Best Answer

The lead needs to be in 1.5lm sections with 100mm laps - by an experienced roofer. 5lm wil split over time due to thermal movement and solar degradation.


Answered 11th Feb 2017

your lead is to long it will crack when it expands and you are correct in the fact it should be flat against the wall, time for a roofer to do the job correctly or a competent builder.

good luck alex


Answered 10th Feb 2017

Any lead guttering needs to have a T-Pren joint welded every 1.5m for expansion and NEVER lapped before the step,as this defeats the object.
A lead gutter needs to be completely watertight as it can carry heavy volumes of water.
Additionally, code 5 lead is the minimum grade of lead that should be used.
I hope you found this advise helpful.


Answered 30th Aug 2018

roofer! you need a plumber who can do lead work properly.


Answered 10th Feb 2017

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