Block paving sand question

[ellal]

I've just cleaned our block paving driveway, and relaid a few areas that had sagged or been moved after building a new side wall.

I then filled in with kiln dried sand and put on a sealant.

However we have just recently had one almighty downpour and much of the sand has washed out. And not helped by the fact that the driveway has an approx 5 degree slope towards the road.

I have read that the blocks need to have a bit of movement, so am I correct in assuming that a dry mix of sand cement (as I've previously used on a pathway) is not the way to go?

Is there anything I can put into the sand to make it more resilient, or is it just a case of brushing in more sand?

Cheers

 

[Ian H]

The kiln dried probably didn't go all the way in due the the sides of the blocks being damp. Any dampness makes the sand clump together and not fully fill the joints.

 

[ellal]

I pressure washed/relaid paving at the beginning of that period of near 30C heat we had (here in the south) and waited several days for the blocks to appear to be absolutely bone dry before applying the kiln sand. So I don't think there was any damp - or none that I could see anyway.

 

[^woody^]

You should re-whacker the surface to vibrate the sand into the joints. Otherwise, no matter how clean and dry you think it is, it isnt, and the sand clogs at the surface

It's flexible paving and cement should not be used. I don't know about lime.

 

[John D v2.0]

Ours is slopey too, I wacked it at first but the top end lost sand for about 6 months, I just kept topping it up. I've no idea where the sand went as it was a good layer of hardcore and sharp sand under, but now the grunge and moss are holding it together!

 

[r896neo]

It happens on any newly installed jointing sand. It doesn't really hold together until it gets a bit dirty etc. Its best to just top it up a month or so later.

There are stabilisers available but they are a bit overpriced for how little they help.

A quality solvent based sealant usually helps a good bit, Thompsons and other such cheap rubbish will have no benefit.

 

[ellal]

I used a solvent based sealant (don't rate water based stuff) and hoped that would help.

But I guess it's back to re-applying the kiln sand.