Adhesion of coping stones - Use of indian sandstone as coping

[PeterW]

I'm nearing the end of an 18 month project Tony on which you've helped me before but at the 11th hour, yet another problem has cropped up. I've laid some 100 sq m of Indian sandstone and decided to cut some surplus stone to use as coping on a small retaining wall around the patio. I asked a contractor to build the wall and lay the coping and I believe he used a fairly standard 4:1 sand:cement mortar. The problem is that the sandstone coping is not sticking well to the mortar bed and with very small effort, I can pick the stones clean (literally) off the wall.

Luckily (or perhaps this was the cause) I hadn't yet pointed the coping which was laid at the end of November. What would you advise: take the lot off, chip out the mortar and start again with a different mix (but I have some 100 stones to do)? Or, can I use an adhesive on the ones which are loose without taking out the existing mortar?

Many thanks

PeterW

[Tony McC]

Oh,that sounds like a cue for Simeon and his marvellous Ronafix product. I'm sure he'll be along any minute now!

If it were me, I'd chip off the old rubbish and knock up a new mortar with the Ronafix added, This could be used to bed and to joint the copings, and because it creates such a bloody strong bond, you should be able to park yer bum on the copings as a temporary resting place, without loosening them.

[PeterW]

Thanks Tony. I've looked at the Ronafix website and will assess the effort when it is light again!

PeterW

[simeonronacrete]

Thanks Tony. Yes, once again Ronafix to the rescue.

Suggets you use Ronafix in your mortar. Keep your 4:1 sand:cement but instead of just using water, instead use a diluted Ronafix:water mix of 1:1. i.e. in a bucket mix half Ronafix and half water. Then add the diluted Ronafix to your cement and sand and mix. Add enough of the Ronafix and water until the mortar is the workability you want.

Use this as your bedding mortar. Damp the surfaces before your start and apply wet on wet, or wet on damp. Take care to avoid getting the Ronafix modified mortar on top of the stone - as it will stick and stain.

For extra secure bond, make up a bonding coat of 1:1 Ronafix:cement and bruch this on to both surfaces before you put the mortar down. This will aid adhesion.

Hope this helps.

See Ronafix for Bonding

Regards

Simeon