ridge tiles mortar ratio

[ash1212002]

i'm having my ridge tiles re-pointed all the old mortar shall be removed, from doing a google search NHBC recommended to use a ratio of 3:1 sharp
sand/cement.

but my roofer has suggested 3:1 building sand/cement rather than sharp sand

what is best/recommended? any other ratios? or use both sharp and building sand?

 

[shane12345]

Sharp sand for ridge? Red sand for me every single time.

 

[yorkie1969]

Mortar ratios are very subjective, many people use their own variation if it works for them, so, whats right and wrong can be deed a grey area.
We use cooks building sand at a ratio of 4:1 with a mortar plasticizer (not washing up liquid) for hips and ridges. We only use sharp sand for flaunching the top of a chimney usually, although sometimes it is specified.
If your roofers mix works for him then I would go with that to be honest.
You will also probably find regional variations of mix ratios too.

 

[ash1212002]

having read other posts i shall be informing my roofer to go with 2:1:1
building sand, sharp sand, cement and 2-3 small cap fulls of plasticiser per ratio

 

[Shane Hart]

I am not a builder, repointing ridge tiles and verge after replacing some tiles. I have used a mix of 1 part builders sand, 1 part sharp sand, 1 part cement. Have already done half of it but just want to check this mix is not going to cause problems as I have read some other posts saying should be 2 parts builders. don't really want to change it as obviously will be different colour just wanted to check this will be ok

 

[Dreuth]

1:1:1 of builders sand, sharp sand plus cement is a bit on the strong side but should be ok. I use a 50/50 mix of sharp and builders sand at 3:1 with cement. Roofs I’ve done 25 years and more ago have no signs of cracking or loosening, as good as the week they were done, I’ve had to redo ridges and verges on new houses only a few years old when just soft (bricklaying) sand & cement was used. Sharp sand is more resistant to frost and because you use much less water is less prone to shrinking, which is very often the cause of the problem.