change of pitch weather proofing

[ForeverYoung]

hello strangers
just wondering what the conventional wisdom is/was about how a change of roof pitch is/was weather proofed/flashed?

existing roof is quite old, maybe 60 years when 2nd story went on.
I think a lot of the steep section was re-clad about 15 years ago.
can't see any evidence of flashing? maybe some sort of sealant under the steep section?

pitch changes from 45⁰ to maybe 10⁰

suspect some water is getting up under the overlap then running down the rafters to exit when it hits the top plate.
photo is of front verandah. problem is around the back where there is no verandah but rooms.
doesn't seem to be wind driven ingress, maybe capillary?

25 - Copy.jpg

[havabeer69]

hello strangers
just wondering what the conventional wisdom is/was about how a change of roof pitch is/was weather proofed/flashed?

existing roof is quite old, maybe 60 years when 2nd story went on.
I think a lot of the steep section was re-clad about 15 years ago.
can't see any evidence of flashing? maybe some sort of sealant under the steep section?

pitch changes from 45⁰ to maybe 10⁰

suspect some water is getting up under the overlap then running down the rafters to exit when it hits the top plate.
photo is of front verandah. problem is around the back where there is no verandah but rooms.
doesn't seem to be wind driven ingress, maybe capillary?

25 - Copy.jpg

a photo of the rear would help... rather then a photo the non problem area?

[droog]

There are a number of ways to flash the transition but most are part of the design of that section and not an after thought add on.
Quite often no flashing is fitted, leakage is more likely where the lower pitch is minimal, where the joint is facing the incoming weather and wind direction, when the lower pitch sheets do not extend far enough behind the junction or the sheet ends are not turned up.

From past experience sealants do nothing if the design is not correct.

One option is an angle flashing the extends up behind the high pitch sheets and then extends out over the top of the lower pitch. The lower the pitch the further the horizontal soaker tray of the flashing needs to extend out.

eg https://www.westernstatesmetalroofin...trim-flashings

[r3nov8or]

droog's 1st paragraph describes how mine is done. The sheets on the lower section extend across the highest batten and as far as possible to the upper section's rafters, and the valleys turned up. On the upper section, place a batten close to the lower roof sheet, and the sheet comes down to fit into the corri profile as snug as possible

[ForeverYoung]

... when the lower pitch sheets do not extend far enough behind the junction or the sheet ends are not turned up.
...
One option is an angle flashing the extends up behind the high pitch sheets and then extends out over the top of the lower pitch. ...
eg https://www.westernstatesmetalroofin...trim-flashings

thanks for that.

I remember a few years ago the sparkie lifted a few sheets to get a new circuit to the switchboard, I don't remember any sealant in place. The sheets were not lifted enough to see if the sheet ends were turned up. The lower sheets seem to run a fair way up under the upper sheets, maybe as much as 600mm on the front verandah side. Don't know about the rear.

[ForeverYoung]

a photo of the rear would help... rather then a photo the non problem area?

same pitch issue.
a photo won't help since a tree fell on it last weekend.
if I reroof it I was wondering about how to weatherproof since for a few weeks before the tree fell there was a small leak as I described. I hadn't been able to suss where it was getting in.

IMG_20250907_082647.jpg

[rambunctious]

same pitch issue.
a photo won't help since a tree fell on it last weekend.
if I reroof it I was wondering about how to weatherproof since for a few weeks before the tree fell there was a small leak as I described. I hadn't been able to suss where it was getting in.

IMG_20250907_082647.jpg

The leak may simply be a screw or 2 have lost their sealing washers ie of course if the roof IS screwed and not nailed, as I think I read the roof is 60 yeas old so either could have been used.
Another leak area is the join of the upper sheets to the lower sheets especially if big foot the roofer has managed to dent the lower sheets between the battens which in turn can cause water ingress into the lower sheet side laps.
Another problem can be caused by build up of leaves stopping the flow and in turn pushing water through the side laps.
Simple start would be to have a flashing made to go from under the upper sheets to over the lower sheets and be scribed into the lower sheets.
Usually called an apron flashing and is made to suit the roof pitches by any sheet metal shop/plumbing supplies.
When fitting an apron flashing be sure to turn up each end even 10mm so water cannot run off the end into the soffit area.

Just read the original post and there should be NO sealant at the junction of the 2 sheets as this will actually cause leaks.