How far back should a roof be stripped for a total re-roof?

A total re roof

The roof should be fully stripped back to the trusses, "non breathable slabs" I'm guessing this was done in thinking it would make the home warmer? when in fact it will cause condensation to build up in the loft spaces. if the home is semi detached and the tiles are going to be a different profile, then I recommend the roofer explaining to the neighbour that they are installing a new roof next door and will have to remove some of their tiles to fix a dry fix bonding gutter to successfully achieve a watertight seal. As far as Osb is concerned, I know they do this as standard in America and I think it's a great idea! however this would have to be discussed first for obvious reasons as its not really a standard thing here, but it can easily be done yes, i would suggest to maybe install a form of rock wool insulation in-between the rafters in the loft space fixed in place with roof battens or any suitable timber. I hope this helps.

depending on the condition of the roof? if all needs stripping. then take off old battens. and old felt.so it leaves the trusses. refelt and batton.roof tiles? new or use existing. depending on advice? felt and batten load up roof with tiles layout .reoint any ridges and valleys etc. Every roof is different. better advise once the roofer is there to check the roof out then advise the client. and listen to their needs. regards lawrence roofing . tony lawrence. p.s scaffolding? health and safety.

Remove all features back to the rafters, this will include: Tiles Batons Underlay/felt Replace all with new (some tiles may be worthy of keeping for reuse purposes).