Slate roof ridge tiles Help

[deema]

My house has a Welsh slate roof, and it’s started to leak! So, having the can do attitude I’m in the process of fixing it. I had it reroofed about 15 years ago by Bodgit and Scarper it would appear as after raking the ridge tiles off this is what I found!!

 

[julianf]

Photos not loading for me...

...scrap that, got them now!

 

[deema]

So, I’ve started to replace the broken slates which is all going well. I’m using Hall Hooks for slates within the body if the roof.
The question is, what’s the best way of cementing back on the ridge tiles to get a flat and straight line. They are the triangular variety that overlap each other. I understand the tiles should rest on the mortar and not touch the slates.

What’s the best mortar mix, google suggest 3 sand to 1 cement with plasticiser?

 

[Adam W.]

3:1 is a hard mix and may crack. I used to use 4:1:1 Sharp sand : cement : hydrated lime to create a more fatty mix. Then laid the ridge tiles on a stiff mortar bed along a batten to get them straight and pointed it all in afterwards.

 

[Spectric]

A slate roof should have lasted more than fifteen years, the ridge on my sheds slate roof was done using ridge tiles that were fixed using some adhesive material on a roll, something similar to this

https://www.marley.co.uk/blog/how-to-fix-ridge-tiles-to-a-roof

 

[Dibs-h]

@deema - my advice would be not to use mortar. Google "Dry Ridge Systems".

I used them on the house and the shed and decades later - zero issues. I think Spectric linked to one.

 

[Jacob]

I'd be inclined to cap the ridge with lead and regard the ridge tiles/mortar as just the weights to keep it in place, even if mortar had cracked or been washed away. It's a critical part of the roof, most likely to fail first and worth spending that extra few quid.

 

[Jones]

A few top corners missing won't make your roof leak, some slates are triangular head and they work fine. The problem seems to be they have been recycled and re-holed with the new hole above the old so water running down the roof will get through. To bed the ridge I use a hydraulic lime and sand mix 2.5 to 1 though sand, cement and hydrated lime is ok .

 

[baldkev]

Dry ridges can be great, but make sure where the screws pass through the base strip, theres a rubber seal. Some kits just have the screw through a steel plate pressing on the base strip, but they can leak a small bit, so best to add washers inbetween screw and metal plate ( ive done that )

To reuse your existing, i like jacobs suggestion of lead, with patination oil, but you'd presumably have to keep it back from the leading edge of the ridge tiles for the cement .

As jones said, theres an original nail hole right over a joint underneath and i doubt theres much headlap, so worth really looking at those spots and consider sealant.....

 

[Seascaper]

So, I’ve started to replace the broken slates which is all going well. I’m using Hall Hooks for slates within the body if the roof.
The question is, what’s the best way of cementing back on the ridge tiles to get a flat and straight line. They are the triangular variety that overlap each other. I understand the tiles should rest on the mortar and not touch the slates.

What’s the best mortar mix, google suggest 3 sand to 1 cement with plasticiser?

Hello,
The mix should be 5:1 with 1/2 of lime. 3:1 is too hard and will cause problems for future repairs as it will cement together all the roof parts and you will have to break everything to get the components apart. 5:1 presents this. Lime is added to make the mix more flexible. You should add a waterproofing additive to the water plus a frost-proofer if you are doing in the winter. Running along your ridge you should have a lead capping. This should run the whole length under the ridge tiles. It comes in different roll widths 150 down each side. Thickness of lead should be code 4. The lead should not be nailed, the ridge tiles and mortar are enough. Start with a ridge tile at each end, fasten a brick line to run at the apex of these ridge tiles and lay to this line. Cover overnight with something light to prevent any rain and stop mortar run off on to tiles. Mr Bodger would forget the lead, think about a strip of roofing felt but would be more concerned about getting back to his van and the Sun.
Regards