Porcelain Slab Fall Correction

[Ralph]

We have a single large porcelain slab at the back door, laid on a full bed of motor on top of a compacted sub base. There's clearly not enough of a fall as water sits on it.

 

Do you think I need to lift the whole slab up and re lay it or can I dig out some of the sub base along the front to increase the fall? I'm really trying not to damage it as we don't have any spare and I'm pretty sure they have been discontinued.

[Canski]

If it has been laid correctly with slurry primer it will be an interesting experiment to try and lift it off the mortar bed. Removing the sub base to increase the fall would be equally interesting. I'd try and lift the slab first by inserting a bolster between the slab and the mortar bed.

[Ralph]

It was laid with primer etc so I just can't see me getting it away from the mortar without damaging it. Maybe best just left.

[nod]

If it’s been laid properly You will damage it trying to separate it from the mortarBetter to dig under it at either side near the house Then lever it up Fill with semidry mortar 

[Dave Jones]

its surprising just how much is needed to drain a single slab, porcelain especially the textured ones love to hang on to water. You would be better of slotting it with a grinder to drain it either side.