Roofing battens

[greenpeg]

How to fix slating battens across gable walls?
The gable end of my extension is constructed with two leaves of 100mm block and 45mm partial cavity fill (75mm cavity) The roof is a tradional cut roof with the last rafters finishing approx 40mm from gable inner leaf the rafters sit on steel I beam purlins(timber plates bolted to beams for rafter nailing) The steel beams finish on the inner leaf and do not extend into cavity. The gable end is to have no overhang i.e no barge/fasia boards. Get the picture? what is the best method of fixing slating battens across the top of the gable wall to give slight overhang for water dripoff.

 

[noseall]

you will be able to extend the roofing lathes (battens) onto and slightly past the gable end (usually 30mm). the tiles will be supported on these battens.

the mortar bedding, onto which the verge tiles will be secured, will require a 150mm cloak, or soffit /cement board fitted beneath the lathes. this will over hang the gable masonry by 50mm, slightly more than the lathes. this is so that the lathes don't show through the mortar.

 

[noseall]

ps if you are going to render the gable end, it might be worth extending the lathe and cloak overhangs by 20mm each.

 

[greenpeg]

Are the battens fastened to top blocks of the gable wall or do they just sit on them and if so, will they bounce when nailing slates on.

Ta.

 

[noseall]

the cloak will need bedding onto the gable masonry. by bedding it you will end up with the cloak slightly higher than the rafters. this will then cause the lathes to bend up slightly at the verge, creating tension within the lathe.
this will help steady the lathe until you secure the verge tiles with either mortar or the dry verge system.
once the mortar has set, the lathes will be solid, but yes, there may be a little bounce in this area.

 

[greenpeg]

Thanks for replies. Is it a requirement to close the cavity at the top of gable wall (for building control)
and if so would you use a wide cloak bedded onto the external block and across to inner skin, Where in building regs does it cover cavity closing?