mortar between paving slabs is disappearing!

[teddyb]

Hi there,
With all the heavy rain etc that we've had recently, the mortar between paving slabs has come out in places. Is there a simple product/method of replacing it?
Very grateful for any help offered, thanks!

 

[r896neo]

Re-pointing is a simple but time consuming and labourious job. You need to remove whats there down to a depth of at least 25mm/ 1 inch.

Then replace the pointing use a damp semi dry mix of 4:1 sand to cement.

Personally i like to use plastering sand but many use building sand.

What type of paving is it? If its natural stone of any kind much more care is needed becuase if you have any cement smears you might not be able to use acid to wash them off.

Do not listen to anyone who recommends any product or dry mix that can be simply brushed in. Its too good to be true and doesn't last at all.

 

[teddyb]

Thanks for your advice. The slabs are old (and many!). They are not natural stone, more like old fashioned concrete square slabs.

I had heard of the dry mix and was tempted to have a go at that - but your words have made me change my mind! Thanks, once again.

 

[JohnD]

you can get a simple tool that injects the grout, rather like a cake-icer.

 

[r896neo]

Yes mortar guns work quite well as long as you use very fine sand like building sand. The secret to good pointing in my opinion is good firm ironing of the joints with a jointer.