On Sunday, 6 March 2016 22:47:40 UTC+1, Chris French wrote:
In message ,
writes
These sheets are nothing but cardboard covered in bitumen.

don't have whatever post you are replying too

That will probably be because (according to Google groups) it dates from
17th May 2006! So not *quite* a decade old - but close enough.

What sheets? Presumably you are talking about corrugated bitumen sheets
eg Oduline?

They sag with any weight of rain or snow on them and need bracing at
600mm intervals max. I did my son's garage last year and now it all
needs replacing. Total rubbish!!

Friends have this on an outbuilding, it has been fine for years. Sounds
like you didn't follow the installation instructions properly.
--
Chris French