804 on existing path

karlitob

Hi all

I’ve an existing path which the previous owner put in. It’s not consistent through the whole length but it seems to be 100-150mm of concrete and about 50-100mm of large stones/rocks underneath.

There are cracks in it which I put down to no expansion joints but it’s solid as a rock. I would prefer not to lift it and lay my sand/cement bed (30mm) and porcelain (20mm) on top.

I’ve yet to figure out my levels - but presumably putting sand and cement directly on the concrete is not the best idea for longevity. So I’m wondering is there an acceptable/minimum depth of 804 that should be compacted on top of the concrete path.

Hope that makes sense.

garv123

why sand and cement? why not cement the the patio tiles straight onto the existing cement?

karlitob

garv123 wrote: »

why sand and cement? why not cement the the patio tiles straight onto the existing cement?

?
I’m planning on putting a sand/cement mortar bed under each porcelain tile.

My query is whether I can put directly onto the concrete path or do I need to put a minimal amount of 804 onto the concrete path. I haven’t checked my levels yet so I may need to bring up the level a little with 804.

Wildly Boaring

karlitob wrote: »

?
I’m planning on putting a sand/cement mortar bed under each porcelain tile.

My query is whether I can put directly onto the concrete path or do I need to put a minimal amount of 804 onto the concrete path. I haven’t checked my levels yet so I may need to bring up the level a little with 804.

No
I'd not use 804
If the levels are too low for sand and cement bring up the level in another layer of sand and cement or a layer of grit.

804 is too large.
It'll just want to segregate and move on top of the concrete.

By "grit" I mean quarry screenings. Should be no larger than about 5mm and mostly fines

Edit.
Sorry unless you've to make up a large level differential. Say 100mm??

jack of all

The problem as I see it is that any cracks in the existing concrete path will most likely telegraph through to the tiles you want to use. Maybe you could introduce some saw cuts in the slab and movement joints in the tiling through metal trims but it is a gamble. Your existing slab will continue to move and you can't ignore that problem

Wildly Boaring

jack of all wrote: »

The problem as I see it is that any cracks in the existing concrete path will most likely telegraph through to the tiles you want to use. Maybe you could introduce some saw cuts in the slab and movement joints in the tiling through metal trims but it is a gamble. Your existing slab will continue to move and you can't ignore that problem

I don't think they will
Just use something flexible like sand and cement between them.
Don't put tiles straight into the concrete

Calahonda52

are the porcelain tiles non slip garden when wet?

e.r

If you have the heights,
50mm sand and cement screed on top of
1000 gauge polythene layer, this will prevent the previous cracking in the concrete from reflecting through your new tiles.
Then fix your tiles with good flexible tile adhesive & sbr primer to the back of the tiles.

karlitob

e.r wrote: »

If you have the heights,
50mm sand and cement screed on top of
1000 gauge polythene layer, this will prevent the previous cracking in the concrete from reflecting through your new tiles.
Then fix your tiles with good flexible tile adhesive & sbr primer to the back of the tiles.

Thanks for that.