Flashing materials for rooflights

[jesteh]

I've got couple of large rooflights (2.1 x 1.5m) which have to be flashed manually (no flashing kit).
We have experienced local roofer doing them and he's a bit concerned with them leaking with having to be manually flashed.

His concern is about flashing them with lead - he says that lead really goes in lengths of 1.5m and then has to start as a new join which is less than ideal for rooflights.

Also, he's mentioned there is not not enough height to the frame for lead flashing so you'd have to build them up from below (which would make them stand proud which is not what we would have liked).

Overall, he felt that it would be better to flash with something else rather than lead - I know there are number of polyethelene and similar type membranes. He's asked me to find out from manufacturers what they would recommend. Any thoughts on forum on what would be a good material?

Cross posted in Building forum...

 

[Alastairreid]

Dont see what the problem would be doing them in lead!

Other option i would consider would be grp. (fibreglass).

 

[jesteh]

I think he's concerned that there is not enough height on the frame of the rooflight to allow for lead flashing. Apparently with lead you have to put in a certain vertical length of flashing for it to be effective - or so I am told. Alternative is to build up the frame but thats going to make them look very high compared to the roof level.

 

[Alastairreid]

Without seeing the job its difficult to comment.

I have constructed rooflights in the past using 75x50mm on slated roofs and leaded the whole thing, looks good if done properly.
Your roofer is correct in saying you would need a decent upstand on the lead to weather properly.

 

[datarebal]

simply up the code and use longer lengths.. check calders site for length applications. 1.5 does not apply to all situations..