Hi all

I bought some 24x14 slates for a repair. They mostly already have four holes. Are they still ok to re-use? I know I have to make new holes when fitting them.

Just to add, the new holes will be lower as they're going on a roof with 20x12s. I'm just using these at the abutment, where I'll cut them down to 20" in length, but needed the 2 extra inches to reach the wall. They are a bit thicker mind, but being at the end I'm hoping they'll be ok (unless anyone thinks otherwise?).

There's also one slate with a diagonal crack/line visible on both sides. It rings ok when tapped and seems sound. Is it ok to use?

Speaking of ringing, one clearly rattles when tapped, so won't use that. The rest do ring and reverberate in the hand, but it's quite a low ring. I've got other slates from another yard that ring higher and longer. Is that normal?

A link to some photos:

https://drive.google.com/drive/folders/1dKah_oULvamtboKW9kKQ4Bcr-sDWaoMF?usp=sharing

Many thanks

The extra set of holes are most likely the result of them having been previously stripped and reused ( possibly on the same roof) the old holes get elongated and enlarged as the slate moves in the weather and heat along with acelerated “rotting” around the hole.
If the slates are to be reused on the same roof then the battens will normally be set out at the same gauge again , so the holes in the slates will need to renewed horizontally. Very unlikely you’d decrease the headlap as you lose some of the weathering capability and visually end up with stripes across the roof as you expose previously covered slate, increase the headlap and you end up needing more slate and may complicate the layout around features of the roof.
Use fixing nails with bigger heads and slightly wider battens and usually you can use existing holes in most sltes or add holes when really necessary.
Just by using reclaimed slates there is a degree of compromise, but you’ll still end up with a perfectly good roof which with decent leadwork will probably see you out.
Far better to reject a slate you have any doubts about , than have to remedy any early failures.

You could repair the unused holes with cement filler if you were worried they might leak?

OK, many thanks for your comments. Intersting, as I'd read in several places that you should never re-use holes and always opt for new ones, but you guys think it's ok to re-use them?

Interesting about the idea of repairing, I've not come across that either but will look into. Any chance of a link to what kind if product to use?

I'm still on the fence as to whether to use them or see if I can buy some others. Different ones I've had in the passed have just had two small holes per slate, and rang higher and truer when hit with a knuckle. As said above, these don't sound dead, but certainly duller than others I've had (but that could be due to the size and thickness?).

Thanks again for all the help.