Roof pitch

[Ozy Oz]

Question on a roof pitch

 

[Ozy Oz]

Hi please can someone advise?
Iam currently doing a single story rear extension and am about to tile roof. It is a low pitch so am using sandroft 20/20. The chippy told me the pitch was 15 degrees so I went for this tile and have done a 100ml overlap. It is now felt and battened and just about to start tiling and thort I would double check the pitch and I’m only working it out to be 13.5 degrees. Will that still be ok???

 

[catlad]

?

 

[Ozy Oz]

??

 

[Doggit]

How have you worked it out, whats the length and the height. The tiles are okay down to 15 degrees, so if you're right, you could be in trouble, and you might be better off chatting with the suppliers.

 

[Ozy Oz]

Ok I used a phone app where you put the phone on rafters and it was between 13-14 degrees. Also I found a calculater thing on a website that works it out for you and it asked for the rise which was 41 inches and run that is 171 inches and that came out at 13.8 degrees

 

[Ozy Oz]

The suppliers I no will only garantee me to 15 degrees. Would 1.5 degrees make a difference? Thanks for your advise!!

 

[Doggit]

Which direction are the prevailing winds from. It comes out at 13.8725, but as they are only guaranteed to 15 degrees, you're outside the acceptable range. If you hadn't battened it, I'd have suggested increasing the overlap to about 110mm, but this is the chippies fault, so he either needs to redo it, or indemnify you for any future problems that may occur. It should have been a rise of 45 inches.

 

[freddiemercurystwin]

Which direction are the prevailing winds from. It comes out at 13.8725, but as they are only guaranteed to 15 degrees, you're outside the acceptable range. If you hadn't battened it, I'd have suggested increasing the overlap to about 110mm, but this is the chippies fault, so he either needs to redo it, or indemnify you for any future problems that may occur. It should have been a rise of 45 inches.

How do you know it's the chippies fault?

 

[Doggit]

Check #2; as in " the chippy told me it was 15 degrees". It would therefore be reasonable to assume that it woz the chippy that did it. But you could be right.

 

[Ozy Oz]

The chippy done the rise to the maximum he could due to upstairs windows. He done the max even so it only has a 75ml upstand of lead flashing.
It’s a shame as I have already battened it as I could increase over lap.
Very tricky to no to go ahead and Tile it!
Cheers again

 

[pilsbury]

It’s a shame as I have already battened it as I could increase over lap.
Very tricky to no to go ahead and Tile it!
Cheers again

This is the sort of thing I do.... then later go on to regret.

 

[noseall]

Everything could have been worked out and discussed long before any rafters were cut. No one gives a chuff when there is someone else to blame. Incompetent fools!

 

[noseall]

Is the roof particularly complex? Are there Velux, valleys or any other vulnerable elements to the roof? Or is it a simple 'slab' lean-to?

 

[Notch7]

The chippy done the rise to the maximum he could due to upstairs windows. He done the max even so it only has a 75ml upstand of lead flashing.
It’s a shame as I have already battened it as I could increase over lap.
Very tricky to no to go ahead and Tile it!
Cheers again

Ah, so the chippie built to site constraints, there was nothing else he couldve done. His only fault was he should have got confirmation to proceed to pitch roof at lower angle.

Incorrect pitch is therefore fault of designer.

Doing batten spacing again is the safest option.