How to know how much to overlap tiles (so covering the holes), so I can work out how many I need?

[lozcozard]

I’m quite confused. I can’t find any info about this online…

tiles have holes in to screw them to battens. When overlapping tiles the top tile cover those holes on the tile underneath.

But all the tiles I looked at online don’t give the dimensions of hole distance from top.

So how do I know what the overlap distance is in order to work out how many tiles I need? Are the holes a standard or maximum distance from top that is known by everyone?

I’ve found online recommended overlap. For example, one site suggests 100mm is ok. So based on that I assume the holes are less than 100mm from the top. As long as they always are then I can work with that. I just need to know the overlap I choose covers the holes on the bottom tile.

Thanks

 

[Notch7]

Have you looked on the manufacturers website - they usually have specification details such as coverage rates and headlamp.

Generally 100mm is the min headlamp, what you need to use is determined by the roof pitch and how exposed the location

 

[noseall]

Have you looked on the manufacturers website - they usually have specification details such as coverage rates and headlamp.

Generally 100mm is the min headlamp, what you need to use is determined by the roof pitch and how exposed the location

Generally 100mm is the max for conc interlocking with 75mm being the minimum depending on pitch and texture.

But all the tiles I looked at online don’t give the dimensions of hole distance from top.

Nothing to do with the holes. Its all about head-lap. Follow manu's guidelines as per pitch of your roof.

 

[lozcozard]

I was looking online at various roofing sites and none of them had any information about headlap.

For example, I was looking at these tiles
https://www.roofingsuperstore.co.uk...nish-natural-slate-in-grey-500mm-x-250mm.html

no detail about headlap. It does say 20 per sq m but I’d like to know the overlap amount.

I may drive up to a local slate file stockist and take a look and ask them.

 

[Diver Fred]

Are you asking about Slates or Tiles?

Slates are fixed approximately 2/3rd from the top. Slates have a double lap.
Tiles are fixed at the top.

Does this help?

 

[lozcozard]

Slate tiles.

the link is very useful thanks. But looks like I’m after a value for the gauge + headlap, which is the overlap of the tile, so I can work out how many I’d need to buy.

All the pictures online show holes approximately half way between 1/3 and 1/2 from top not 2/3rds? Like in your diagram. Eg this https://www.roofingslatedirect.com/?gclid=EAIaIQobChMIt7HW_7jn9gIVhY9oCR0L9ga8EAAYAyAAEgLLQ_D_BwE

If I bought a 500 x 250 tile are the holes the same distance no matter what tile? If so, what is that distance on a 500 tile? Or I could find a website that states the headlap + gauge and apply that to another slate if the holes are the same position as standard.

Or knowing that it’s less than half I could just assume an overlap of half the height so use that to work it out?

Thanks

 

[datarebal]

250 x 500 20 per M2 at the correct pitch and headlap .
You can order preholed to suit head lap required.

 

[noseall]

Slate tiles.

3 posts later and the OP decides its slates not tiles.

For the record:
Slates, concrete interlocking and plains all furnish a roof but are distinctly different.

 

[Notch7]

Generally 100mm is the max for conc interlocking with 75mm being the minimum depending on pitch and texture

My apols for giving some incorrect info, thanks for correcting.

 

[noseall]

My apols for giving some incorrect info, thanks for correcting.

Not really incorrect, nor is my info' binding. It's more to do with if you want things like dry verge to work, then stick with the recommended max/min laps.

 

[Diver Fred]

From the link I sent more information

Info on fixing Slate roofing ('gauges', overlap & headlap + reasons why a slate roof has a double lap)

Batten spacing (Gauge).

Don't forget you also need as many 'Slate & Half' slates as you have rows of slates.

 

[lozcozard]

Hi All. As per my mistake on this other thread https://www.diynot.com/diy/threads/think-i’ve-messed-up-the-baton-spacing.590331/ it turns out the answer to my question is very simple, and so very perplexing why there is lack of this info online and not answered here, and even the roofing merchant didn't tell me.... all the websites about "calculating" headlap are pointless for pre-holed slate, as there can only be one headlap due to pre-holes. (unless you want less headlap and put in extra battens)...

I was wondering how slates nailed in near the centre would not wobble due to nothing securing them at the top... I realised from looking at images online the top of the slate needs to sit on the batten above. Its only apparent in images, I could not see any description of this fact. I also found one video saying this after I fit my battens!

So therefore the answer to my question is easy... the top slate needs to overlap so its holes are just higher than the slate underneath it so you can nail into the same batten the top of the slate underneath rests on. So in fact its only about 1cm to 2cm less than the distance of top of slate to holes. So on my 500 x 250's, where the holes are 18cm down, my battens need to be 20cm apart which gives 2cm of slate resting on the batten at its top.

I guess all the websites online that state depends on the pitch and how windy where you live assume you are putting your own holes in and can decide on the headlap yourself, and not buying pre-holed ones. I didn't even know they come without holes as all the slate at the builders merchants are pre-holed. So if its preholed you cant decide on the headlap if you want the top slate resting on the batten, its fixed depending on the hole distance. Unless you want less headlap and add in more battens to support the top of the slates. But you certainly cant have more headlap.

 

[datarebal]

Oh dear ... Yes you can increase head lap. To much over thinking

 

[lozcozard]

Oh dear ... Yes you can increase head lap. To much over thinking

Too much overthinking? It saved me having wobbly slate . And no, with pre-holed tiles I could not increase the headlap because the slate holes will be above the slate underneath. I could decrease it, but I would have to add more battens.

 

[datarebal]

You would have had a wobbly slate because you didn't have a clue . And asked the wrong question.
Glad you sorted it