I don't know if its been mentioned here previously, but the standards for pitched roofing was updated earlier this year.
This has been done partly as a result of crap workmanship and claims against the NHBC warranty, but the cited reason is to guard against more extreme weather events, and harmonisation with Euro standards
The key changes are
Tiles
All tiles have to be mechanically fixed - either a clip or a nail. Tiles at the perimeter must have at least two fixings.
Mortar bedding
All ridges and hips must be mechanically fixed - even if bedded with mortar. Or use a dry-fixed system.
Underlays
New standards for roofing underlay, and batten spacing. Membranes must not be able to push tiles up, or flap about.
Battens
19mm battens no longer permitted
This blog seems to sum things up, but check out the sites of tile suppliers for more information.
www.roofinglines.co.uk/blog/?s=changes-to-bs5534
Also www.labc.co.uk/news/new-code-practice-spells-changes-roofers
TBH, all of the above are problems caused by poor quality work and unskilled workers. But the industry has persuaded the standards writers to create a market for more products. I see more problems with modern roofs than roofs 50+ years old.
This has been done partly as a result of crap workmanship and claims against the NHBC warranty, but the cited reason is to guard against more extreme weather events, and harmonisation with Euro standards
The key changes are
Tiles
All tiles have to be mechanically fixed - either a clip or a nail. Tiles at the perimeter must have at least two fixings.
Mortar bedding
All ridges and hips must be mechanically fixed - even if bedded with mortar. Or use a dry-fixed system.
Underlays
New standards for roofing underlay, and batten spacing. Membranes must not be able to push tiles up, or flap about.
Battens
19mm battens no longer permitted
This blog seems to sum things up, but check out the sites of tile suppliers for more information.
www.roofinglines.co.uk/blog/?s=changes-to-bs5534
Also www.labc.co.uk/news/new-code-practice-spells-changes-roofers
TBH, all of the above are problems caused by poor quality work and unskilled workers. But the industry has persuaded the standards writers to create a market for more products. I see more problems with modern roofs than roofs 50+ years old.