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Since roofers seem to clock off at 2pm and are probably all in bed, and I need answers quite urgently, I'm posting this here. It is a building related issue anyway as touches on different factors.
Hello,
Where the roofs of my existing house and extension meet at the GRP ribbed valley tray, the tiles on the existing roof seem to kick up a bit at the end so you can see a slight wavey effect when you view it from further back. Not nice and straight.
This seems to boil down to the rafters on the existing house being less thick than those supplied with the truss roof of the extension. Therefore, the roof battens of the extension sit a little higher and so do the tiles. These tiles then do not need to ride up over the ribs on the side of the GRP valley. The tiles on the existing house though, being a bit lower (maybe 10mm) have to ride up over these big ribs causing the slope effect.
The only solutions I can think of are:
- Just leave as is, although it is a bit grating to look at. I've attached photo but not as obvious as in reality.
- Replace the GRP ribbed valley tray with one that doesn't have high side ribs. Do these exist?
- Use packers under the battens on the existing roof further along from the valley and try to achieve a more gradual build up so the end tiles at the valley tray do not obviously kick up.
Thoughts?
I suppose we could use less thick ply under the tray to drop it down a bit and make its ribs lower but this could then be a problem for the extension tiles where they meet it (they might then want to drop down to the ribs). Unless we make it lower only on the existing house side (say 6mm). The ply is about 18mm thick which is about the height of the tray's side ribs. Different thicknesses on each could put the valley tray under pressure though and make it wonky?
Speaking of which, I've checked how the roofer, who did the roof of my main house two years ago, managed to avoid the tiles riding up over the ribs... he achieved this by not putting any ply valley boards under it. Just screws in to some rafters... should I be worried about that?
I'd appreciate advice.
Hello,
Where the roofs of my existing house and extension meet at the GRP ribbed valley tray, the tiles on the existing roof seem to kick up a bit at the end so you can see a slight wavey effect when you view it from further back. Not nice and straight.
This seems to boil down to the rafters on the existing house being less thick than those supplied with the truss roof of the extension. Therefore, the roof battens of the extension sit a little higher and so do the tiles. These tiles then do not need to ride up over the ribs on the side of the GRP valley. The tiles on the existing house though, being a bit lower (maybe 10mm) have to ride up over these big ribs causing the slope effect.
The only solutions I can think of are:
- Just leave as is, although it is a bit grating to look at. I've attached photo but not as obvious as in reality.
- Replace the GRP ribbed valley tray with one that doesn't have high side ribs. Do these exist?
- Use packers under the battens on the existing roof further along from the valley and try to achieve a more gradual build up so the end tiles at the valley tray do not obviously kick up.
Thoughts?
I suppose we could use less thick ply under the tray to drop it down a bit and make its ribs lower but this could then be a problem for the extension tiles where they meet it (they might then want to drop down to the ribs). Unless we make it lower only on the existing house side (say 6mm). The ply is about 18mm thick which is about the height of the tray's side ribs. Different thicknesses on each could put the valley tray under pressure though and make it wonky?
Speaking of which, I've checked how the roofer, who did the roof of my main house two years ago, managed to avoid the tiles riding up over the ribs... he achieved this by not putting any ply valley boards under it. Just screws in to some rafters... should I be worried about that?
I'd appreciate advice.
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