Why are ridge tiles crap, or am I missing something?

[asnoop20]

I've never done roofing before but now I've done membrane, tiles, flashing and now I've had to replace a half-round ridge tile.

The ridge tile butts up to the other ridge tile but there's no lapping, t&g etc. The existing ridge tiles have broken tiles placed underneath then a dollop of mortar sits on the broken tile and meets the butt, then extra mortar fill the small void.

I can see however that the mortar on all the ridge tiles has failed at some point (to be expected with movement) and someone has gone over the butts with silicone. The mortar used to make double-roman tiles flush (gap filling) is also crap imo.

Am I missing something or are ridge tiles mechanically crap for waterproofing?

I've filled the butt with silicone instead of mortar in hope it'll last longer as this will be the first point of water trying to get in. I am however unhappy, it feels like I'm doing a bodge.

 

[Wayners]

There are dry ridges now but often to repair the roof needs to be good and lined up straight, and ridge needs removing and setting on new mortar.
Mine was done in 2007 and still good.

Problem is, local trade will climb up and butter over ridge joints for a few hundred which is pointless.

 

[asnoop20]

I was missing something. I've took them off to convert to dry ridge and found most have a piece that goes inbetween and has a groove on each side which the tile sits in. This provides the waterproofing between the tiles. I believe it also has a wavy bit to fill in the double roman pattern but it's difficult to know if that was added later.