Ridge tile on fibre cement slates

[EdTurtle]

Hi, just after a bit of advice regarding fitting concrete ridge tiles to fibre cement slates on a small shed. Tiles are like this with the (I think its called) capping:
https://www.ashbrookroofing.co.uk/a...rete-ridge-tile-110-degree-shallow-pitch.html
My roof is 20deg, so I am using a 135deg tile, which is pretty close to the tiles, but theres a small gap. There is no hole in the ridge tiles.

Whats the best way to fit these? I was thinking of a 3:1 mortar mix, but that gives me two questions: Firstly, how to stop the mortar slipping down the smooth tiles? Secondly, what do you do where the two ridge tiles meet, ie under the capping?

Thanks

 

[Alastairreid]

 

[EdTurtle]

Thanks, thats not a bad video. I dont have the holes though to screw through, or even a ridge batten, does that matter? Is the silicon essential, or would mortar be ok in the gap under the caps?

 

[datarebal]

With cement fibre it's important to bed properly include the butt joints ensure the mortar grips around the skate edges.
In the video they don't bed the butt joints just mastic them .. and they never filled the bottom of the first ridge . The top ridge they never fitted should have been cut to shape before they bedded the second ridge down.
Top ridge should be whole with the angles cut.
Second ridge down is cut to length.
Basically never put a cut on the end of a run.