Pointing on a new patio....

[jjmichalski]

About 3 months ago we got a new patio laid by a builder at quite a hefty cost due to the size of space, about 60 square metres. We used sandstone slabs, 4 different sizes. All looked lovely when finished.

At the time I admit I was puzzled with the pointing, it was a dry sand/cement mix and not the older way of wet cement pointing. I was assured this was the "new" way to do this and it would set in time to form a hardish, although not solid, pointing.

We live in Kent and in the past 6 weeks have received a lot of snow as has much of the UK - anyway, I digress, but today I went out on the patio and I can feel movement in some slabs, only a little bit, but certainly movement. Also the slabs around the edge have started to come up and a lot of the pointing is now soft to touch and can be brushed out using only my finger.

My question is, is this method of Sand/cement dry mix the best way to point this type of patio? I want to talk to the builder to get him back to do it as not happy but wants some thoughts on alternative pointing methods.

Also, the slabs around the edge are not flush with the walls, apparantly you no have to leave a 2 inch gap for expansion - is this true?

Thanks for reading this essay and look forward to your thoughts and comments.

Dan

any of you ever heard of a mortar gun like a silicone gun but you put wet cement in it, 4 red building sand 1 cement and some wather proofer liquid this will stop the frost getting in to the joint.
sandstone needs to be layed on a wet bed, i use 4 to 1 mix, 2 washed sand for strenght and 2 red building sand for adhersion to slab and 1 good cement ie rugby.

 

[WabbitPoo]

I did make the mistake of splashing out on a mortar gun cos I had a massive area to re-point for someone. Just could not make it work properly. All the water squeezed out and created a hard lump of mortar that would not squeeze thru the nozzle. Think I've chucked it now, but any idea where I was going wrong?

Oh and I agree with your laying method.

 

[jjmichalski]

I did make the mistake of splashing out on a mortar gun cos I had a massive area to re-point for someone. Just could not make it work properly. All the water squeezed out and created a hard lump of mortar that would not squeeze thru the nozzle. Think I've chucked it now, but any idea where I was going wrong?

Oh and I agree with your laying method.

best using silver sand its very fine and does'nt glog up the gun also make sure you use plasticiser, this makes the mix smoother, i use an everbuild product that has a plasticiser and waterproofer in it.
Joe