Lead Flashing #2

[ali68]

Getting ready to put some flashing on the roof, couple of questions if you don't mind.

I have an approx 200mm difference in roof levels (new roof lower than existing) therefore I will need to flash between new and old.
New roof just sits approx 10mm above lower edge of the existing barge boards.

I will need to remove the cloak verges and lead underneath these come down the barge board and then lap onto the new roof by approx 150mm.

Would a tilt/fillet be necessary at the base of the barge board to kick the lead out slightly before lapping onto the new roof? or is a vertical drop sufficient. 25 degree pitch 4.8 long and Double Roman tiles.

Lead will be in 1500 lengths and lapped 220mm.

Attached a quick sketch of the 2 options!!

Once again thanks for any help

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[noseall]

no need for a cocking fillet with lead.

 

[redtonybbb]

TonyB./Ex Roofer advanced C&G/Chartered Surveyor.This plan of yours does not look right.It would be better if I had an actual photo,anyway you say the barge board comes slightly below your roof tile.Have you considered leaving the old roof as it is and puting in a secret gutter.That is to say if you had secret gutter section made up in code 4 in 1.5m lengths..you would be able to slot up under the barge board 75mm min.with the fixing for the gutter section being at the top of the section,which would be overlapped by 150mm by the next section of secret gutter.If this worked it would save a lot of messing about.

 

[ali68]

Thanks noseall clears that one up.

Added some pics for you Tony, if it helps to clarify things. The roof is sarked with OSB by the way.

Looking up the roof towards the ridge

Close up

Perhaps a little to far away to see any detail

 

[redtonybbb]

TonyB-Ex- Roofing lecturer/Chartered Surveyor.
Hi-Thanks for the photos.You have 2 options the first is to use a cover flashing over the double romans(1.5m lengths in 12 inch code 4) with the upstand going as high under the cloaked verge as required 75mm as a min-100mm .(you have to take the cloaked verge off in any event.(just place on older roof 1m back for re-fixing).Make sure you use the undersarking/felt to go up the facia and either under or over the existing felt(150mm).You will have to take out any nails holding any batten ends into bargeboard.Secondly you can install a secret gutter if you find that your roof tiles will be too high to re-fix your cloaked verge. you will have to set the roof out from the gable on the new roof back to the cloaked verge on the old roof which will either come in as a full tile or cut/double romans are ok for cuts generally.

 

[ali68]

TonyB-Ex- Roofing lecturer/Chartered Surveyor.
You have 2 options the first is to use a cover flashing over the double romans

Thanks Tony one point, would this be the new tiles you are speaking about here?

Other than that I get what you are saying, thanks again for the help

 

[redtonybbb]

TonyB.Yes the new tiles.
1.Take off cloaked verge and carefully set aside as they will be fragile and if broken matching would be difficult.
2.Lath and felt new roof allowing felt upstand up and if possible 150mm beneath the felt of the old roof.(on top is ok for this if the old felt is too fragile.
3.I would set the new roof out/ from the end cloaked verge on the new roof ie the edge of the water bar to the distance of the third tiles water bar,once the distance is established you can mark every third tile right to left to the abutment,however on the otherside you would take your mark from the tile immediately to the right of the cloaked verge as the cloaked verge does not have a water bar. Strike the roof for verticle joints for tiling.And firstly place my tiles or cuts to the abutment,so the lead cover flashing can be installed...dress tightly allowing the lead beneath the older roof battens if necessary,as the fixing through the batten ends would hold the lead.
4.Replace the cloaked verge.
The benefit of working like this is you are not clambering over your new roof causing any damage.carrying lead and walking up and down completed roofs can be avoided sometimes.It works out easier taking the time to set out and you cannot get the tiles straighter if set to a line.