patio on top of slabs

[billozz]

hi guys i have an existing patio consisting of 2x2 slabs and would like to cheeer it up a bit and put down some different slabs, am i right in assuming that it will be ok to lay straight onto the existing ones?, they are very solid and show no signs of movement at all.
thanks
Bill

 

[r896neo]

If you are certain they are solid and you have enough clearance under your dpc then go ahead.

They would of course need to be layed on a full mortar bed not sand.

 

[billozz]

sorry i should have explained there is no dpc, i am laying this next to a static caravan. can you explain how i make sure that the slabs run parallel to the caravan, as there isnt a wall to run along, i dont want to get half way across with the slabs and find that i am at an angle to the van, it might sound stupid but im just not sure how to start off
thanks again
Bill

 

[r896neo]

In that case you want to start laying next to the caravan. Simply lay the first course along a straight piece of timber if its only a small area or use a string-line for longer runs. Just parallel it up by measuring carefully.

Lots of good laying info on paving expert.com

 

[billozz]

would it be a good idea to jetwash the old slabs first ?

 

[r896neo]

Yes. You don;t necessarily need them to bond to the old ones but it would be better.

Clean them well and then the real pro job would be to apply a bonding slurry to the surface as you lay or add SBR into your mortar mix.

SBR can be though of as an outdoor version of PVA. You can buy it in any builders merchant or even b and q.

Add about 100ml per bag of cement.