Porcelain Patio advice needed!

[Sam odell]

I'm laying a porcelain patio, on mortar, half of it on pre-existing raised, level concrete old shed base, half on mot type one that I've raised up to be flush with the concrete. The patio is walled at the back edge and on the left side with mot type 1. The right edge with concrete just has a wooden fence alongside it. (See pic below - you can tell which side is mot and which is concrete)

I'm having issues with the fall as I was planning on having it run down away from the rear and side walls, and off towards the front and right hand side with the wooden fence.  I then realised that obviously as I can't adjust the concrete base, the fall won't work well in that direction, as I end up with the lowest point of the patio (front right, fence side) being too low, about 2.5cm above the concrete base.  

My options are: 

1: raise the whole patio level, starting at the minimum front right (50mm probably??) and raising across the patio, so the fall goes away from all walls, but patio level is overall much higher, which I don't want.

 or 2: Arrange the fall to drain from right to left towards the side wall (this would allow more height over the concrete base side, but means more water towards side wall. If I have side drainage, is this a problem?? 

Thanks

[Temp]

My concern would be different settling between the different bases leading to cracks where they meet. Not sure what others will say but id look to dig up the existing concrete and laying new with reinforcing over the whole tiled area.

[Sam odell]

8 minutes ago, Temp said:

My concern would be different settling between the different bases leading to cracks where they meet. Not sure what others will say but id look to dig up the existing concrete and laying new with reinforcing over the whole tiled area.

That would be horrendous. It's very thick. Would laying enough mortar not be stable enough? Or I could take down the sub base and lay concrete to level it all? thanks a lo

[Sam odell]

14 minutes ago, Sam odell said:

That would be horrendous. It's very thick. Would laying enough mortar not be stable enough? Or I could take down the sub base and lay concrete to level it all? thanks a lo

Also - beneath the mot type one on the left is more of the same concrete base, just lower down. mot is about 2 inches thick, beneath it is thick concrete base.

[Mr Punter]

The easiest way to adjust the fall is with MOT.  I it will be fine, as long as it is properly wacked down.  It seemed that you had already ruled out option 1.  Bear in mind you will have about 40-50mm mortar plus the slabs.  I would not have a fall towards the wall unless it was unavoidable.  If you have to go that route you could have a slot drain against the wall, but it will need part of the slab breaking out to install plus it will need to run to a soakaway.  I specified DekDrain Edge recently and it looked quite good and they deliver small quantities direct.

 

You could have perimeter borders and drain to them but for this you will need to break out lots of concrete.

[Sam odell]

9 minutes ago, Mr Punter said:

The easiest way to adjust the fall is with MOT.  I it will be fine, as long as it is properly wacked down.  It seemed that you had already ruled out option 1.  Bear in mind you will have about 40-50mm mortar plus the slabs.  I would not have a fall towards the wall unless it was unavoidable.  If you have to go that route you could have a slot drain against the wall, but it will need part of the slab breaking out to install plus it will need to run to a soakaway.  I specified DekDrain Edge recently and it looked quite good and they deliver small quantities direct.

 

You could have perimeter borders and drain to them but for this you will need to break out lots of concrete.

Thanks, cant adjust using MOT as only half the base is MOT (as explained). The concrete on the right is flat, which is part of the issue. Can't really add more mot onto it. I think I'll just raise the amount of mortar, raising the overall height of patio, allowing the fall away from walls. To address the issue raised by 'Temp' above, I will ensure mot is well compacted, possibly sprinkle in mix of sharp sand and cement to make it a bit more solid, and then use plenty of thick mortar. Do you think that would be ok? It's not a big patio... thanks

[Sam odell]

Any idea how much SBR+ to use with bedding mortar? Guidance says 200-300ml per kg Cement. Unsure if they mean cement or mortar. Just need to know how much to splash in for say a bucket of mortar. thanks.