Roof Tiles (Inside Loft)

[fcwoods99]

Will be insulating and boarding out loft soon !
Before I insulate between rafters (know rules ect for air gap) want to make sure tiles are ok and sound so no future problems !
The tiles from inside loft seem to be fitted onto rafters with wood running in opposite direction, tiles sit in this timber stripping and rafters and then between is dabs of mortar !!!
THIS OBVIOUSLY DOES THE JOB AS MOST TILES AND ROOF SEEM SOUND !
Some mortar has come out from back off tiles only say 1% of whole area ( seems may be slight water come in at these points, but not enough to drip down)
Want to make rafter area sound for insulation and boarding out so my question is ?
1; Do I just put more mortar on where it is missing (as i say this seems to be how it was done originally! not convinced myself this is enough)
2; Could I run felt between all rafters
3; Do I do both , or what method should I use
Any HELP would be good , thank you Mr Wood

[rigga]

fcwoods99
The tiles are fitted to the tile laths with sand and cement mortar, this is called torching, if you install insulation under the roof covering in between the rafters, how do you intend on removing the tiles when they break you will find that this will be difficult to do as the cement holds down the tile, quite often I have replaced tiles that have been torched from inside the loft by removing the torching and slipping the tile in often used on rosemary or dreadnaught tiles when you over board how are you going to do this you would have to forcibly lift all the tiles from around the one that is broken to get it in then all the torching will fall onto the insulation and roll down the roof to the soffit boxes. As for allowing water in these types of roof’s were done before under felt was used and the tillers knew what they were doing. It also allowed air into the roof space and allowed them to breath, so if you are going to run felt in between rafters make sure it is breathable. Tyvec is a breathable membrane used in most of today’s roofs.

[fcwoods99]

cheers for help