I have a gap between the slabs in my townhouse and patio. There is also a drop between the patio slab and slab beside our house. We had some subsidence issues which have been fixed. Could you please advise how I could best fix the gap between the house and patio slab? I would also like to rectify the drop between the patio slab and slab along the side of the house. If I was to get a trades person to help with this which type of tradesmen would be best suited to assist?
Welcome to the Bunnings Workshop community @NataliaM. It's fantastic to have you join us and many thanks for your question.
Are you sure that the gap between the house and the slab is not supposed to be there? If the slab is higher than the damp coarse line then a gap is most likely intended. This stops the water running off the slab hitting the bricks and mortar then migrating through and up the wall. As I can't see any additional flashing or damp course then you would need to consider laying these before filling that gap.
The difference between the different height slabs could be addressed in a couple of ways. You could build a cement ramp to stop it being a trip hazard or you could attempt to grind down the higher slab. You might also use a combination of both methods.
For creating a ramp if the difference in height is less than 25mm at the highest point Lanko 5kg 136 Rapid Patching Mortar would be a suitable product to use. If the trip hazard is higher than 25mm you can use a combination of Lanko 5kg 189 Bulk Fill Screed to fill and then taper it into the adjoining slab with the 136. Lanko 189 must be laid at a minimum thickness of 10mm and needs Lanko 1L 124 Surface Primer to ensure a great bond.
When applying the Lanko 136 onto the existing concrete or over Lanko 189 you need to ensure the area is clean from contaminants and you'll need to soak the area with water before commencing.
If you were going to try to minimise the difference in height an angle grinder using a DTA 105mm Dual Row Grinding Disc would be suitable. There is a substantial amount of material that would need to be removed to taper the difference in. You might be able to reduce the trip hazard but certainly not remove the height difference completely.
Please let me know if you need further assistance or had any questions.
Thanks for your response. The gap in the slabs has gotten significantly worse after we had our foundation repairs undertaken. During the stabilisation work the patio slab lifted and slid out, which has created the gap.