low pitch roof, ply board or buy new tiles?

[Stephr]

We are in an unfortunate situation where the builder miscalculated the pitch of the roof (single storey lean to extension) to be 19 degrees, we purchased Marley edgemere tiles, the builder laid them and the roof was found to be 14 degrees. The builder has agreed to return and sort out the problem which will involve removing the whole roof and obtaining a minimum of 15 degree pitch as we have two roof windows.
I have spoken to Marley who say we could ply board and install a weather proof sub roof and then put edge mere tiles on top and building control have agreed they would allow this. Alternatively we buy a tile specified for pitches down to 15 like Marley Wessex or sandtoft 20/20. Any advice? Which is the better route to take and why?
Thank you

 

[freddiemercurystwin]

Or you could consider a seamed roof like lead or zinc. Obviously lead is megabucks, zinc however is not. Some people like seamed roof's some do not, but certainly more reliable than any tiled roof, no matter what the pitch is so you could avoid lowering the structure though the only way the rooflights would work is in kerbs to get their pitch higher
If you installed ply and then waterproof membrane, how do you fix the tile battens to it?

 

[catlad]

If your builder can't get a simple thing like the pitch correct then what makes you think he can get the detail of your sub roof correct.