Folks,
I have just done a complex part of a little roofing project, so this is really a retrospective question.
I have 3 roofs, intersecting at one point, 2 parallel and one adj at the back, producing 2 pitched valleys running down into one low pitch hogs valley (sorry dunno the european term for it, will post picture if required.)
The valleys are all code 5 leadwork, cant stripped and welted! Stainless steel nailed on one side only to prevent movement and lapped with a manufactured valley cladding (Makes it easy to slate and gives a nice uniform finish)
My Hogs valley is falling 7" over 15', Thats a 1:25 fall. I couldn't go much higher, I had to accomodate roof lights.
I framed out the hogs valley using 2*4" runners between my parallel rafters on each roof, and knocked in valley supports, again 2*4, running between each rafter runner. I framed down on top of this using 3/4" marine ply, leavin an U channel gettin progressively wider back up the hog.
I lay down left-over radon barrier as a vap barrier, installed cant strips (with galv nails) 5" up from bend on U of hog, on each side. The cants were laid 1/4" higher than battens to allow slight bell on slates.
Yesterday we installed our lead flashing. at the least point its 20" in width, and the most its 46" in width. I used 36" rolled lead sheet, turned sideways (to min off cuts and to make the width at the back). with head laps of 6-8" in max sections of 5 feet, some were max 2 1/2 ft section as the lead was turned. I ended up with 4 laps over the 15ft.
Now the crux of my question, I had another roofer turn up on site and he reckoned I should have stepped the Hog. every 4 feet by 2 inches.
If I had done that, The fall would have been 7 + 6(lets say 3 steps), thats 13" of a fall, my valleys would have been meeting very high and I would have had to lift the roof windows a couple of inches.
My opinion is that the steps are of no real benefit, I cant see how water will spill back up the laps, water running from the back 2 pitched valleys will give any runoff heaps of momentum. (Moss wont be a prob as I am installing copper ridges). I guess the only issue is snow, but its not really aproblem here in this part of Ireland, even if, theres 2 large roof windows to climb out to move it on if nec.
Whats the general opinion on these types of hogs valleys?
thanks
for your time
Pat
I have just done a complex part of a little roofing project, so this is really a retrospective question.
I have 3 roofs, intersecting at one point, 2 parallel and one adj at the back, producing 2 pitched valleys running down into one low pitch hogs valley (sorry dunno the european term for it, will post picture if required.)
The valleys are all code 5 leadwork, cant stripped and welted! Stainless steel nailed on one side only to prevent movement and lapped with a manufactured valley cladding (Makes it easy to slate and gives a nice uniform finish)
My Hogs valley is falling 7" over 15', Thats a 1:25 fall. I couldn't go much higher, I had to accomodate roof lights.
I framed out the hogs valley using 2*4" runners between my parallel rafters on each roof, and knocked in valley supports, again 2*4, running between each rafter runner. I framed down on top of this using 3/4" marine ply, leavin an U channel gettin progressively wider back up the hog.
I lay down left-over radon barrier as a vap barrier, installed cant strips (with galv nails) 5" up from bend on U of hog, on each side. The cants were laid 1/4" higher than battens to allow slight bell on slates.
Yesterday we installed our lead flashing. at the least point its 20" in width, and the most its 46" in width. I used 36" rolled lead sheet, turned sideways (to min off cuts and to make the width at the back). with head laps of 6-8" in max sections of 5 feet, some were max 2 1/2 ft section as the lead was turned. I ended up with 4 laps over the 15ft.
Now the crux of my question, I had another roofer turn up on site and he reckoned I should have stepped the Hog. every 4 feet by 2 inches.
If I had done that, The fall would have been 7 + 6(lets say 3 steps), thats 13" of a fall, my valleys would have been meeting very high and I would have had to lift the roof windows a couple of inches.
My opinion is that the steps are of no real benefit, I cant see how water will spill back up the laps, water running from the back 2 pitched valleys will give any runoff heaps of momentum. (Moss wont be a prob as I am installing copper ridges). I guess the only issue is snow, but its not really aproblem here in this part of Ireland, even if, theres 2 large roof windows to climb out to move it on if nec.
Whats the general opinion on these types of hogs valleys?
thanks
for your time
Pat
