Coping stone overhang

[pjcarter]

Hi
My first post- but very grateful for all the advice I've gleaned from this site over the years.

I've built a retaining wall with 215mm wide concrete blocks and want to top with 300mm wide coping stones. The back of the wall retains the lawn/garden, which will be the same height as the coping stone. I want to clad the front of the wall with timber cladding- 20mm thick cladding attached to 25mm battens. This means the coping stone will need to overhang the battens and cladding. Coping plan.

If I overhang the cladding from the block by 75mm this will give a 30mm overhang from the front of the cladding (and would give a 10mm overhang at the back of the wall). Is 75mm too large an overhang? Will this create tipping issues? I've read other posts about use of bonding agents- will this provide strong enough contact to prevent tipping? The wall will be at a height that it's likely people will walk/sit on it. I'm assuming that if I have less than a 30mm overhang from the cladding the drips will run directly onto the cladding and reduce its life considerably.

The copings I'm looking at are 40mm sandstone (to match the patio). I assume use of 25mm patio slabs would not be sufficient for that overhang as liable to break?

Any help appreciated. I'm aware I could use alternative finishes (render etc) on the wall that would allow me to centre the coping stone but I'm keen to see if this will work before changing tack.

thanks

[lutonlagerlout]

depending on your finished width you need the coping stones to project ideally 35-50mm beyond that
if you use an SBR mortar they should be well stuck
I dont consider indian stone a great coping material,unless you buy purpose cut ones 40mm thick, also they need a drip cut into them
cheers LLL

[Tony McC]

75mm oversail is about as much as you dare risk and it would *definitely* need to be securely ancored, using either SBR mortar with the underside of the copings primed with SBR slurry, or a high-grip outdoor grade tile adhesive suitable for natural stone.

You've possibly already seen this but it does give you all the essential info, including the importance of a drip groove.