Thread: Concreting around pool + excavation

Originally Posted by Paul M

1st timer. Stumbled across site when googling and am quite impressed.
Any advice would be greatly appreciated.

I have read a lot of the threads but am still not sure on the best way to do my next project of laying concrete on a rather clayey soil in North West Sydney.

I am relaying my pavers as I made the mistake of not using concrete first time around 7 years ago and the soil kept moving in some areas.
Area to be concreted is around my pool and generaly approx 2 to 3 metres wide, I will be laying texipave pavers on a bed of mortar with 10mm mortar in joins. I have been informed to leave at least a 10mm gap between pool shell and new concrete for pool movement, will this allow the new slab to shift? If possible, drill and dowell into the ring beam may be an advantage.
When I put formwork around the pool which will sit lower than the coping how do move a screed side to side? You shouldn't have to, this will be up to the concretor to do. The concretor will cut in the edges using a hand trowel, then use a smaller screed to fit between.

Although cracking is not good I am more worried about the concete moving and do not want the coping which is the same paver to be moved by new pavers or concrete. The new concrete will be bottom of coping paver level, then a silastic joint should be used between new and old pavers.The new concrete will also butt up against a footing of retaining wall. Use full depth foam jointex for this to allow expand/shrinkage. It can even come with a sticky back these days so it can be stuck to correct height on the wall.

What type of join should i used between coping and new paving? Foam jointex.
I notice that they used a foam wth a thin layer of mortar on coping.
Should i use additives in mortar?A bit of bondcrete never hurt.
What rating reo mesh should I use?F62 is enough but for peace of mind you could use F72
Should the Reo be placed 1/2 way up in concrete depth or below?Min half way up. 30mm from the top is recommended.
Is plastic under concrete important?
Should I use the bitumen type expansion material between concrete and footing? Foam jointex would be better to allow max. expansion. When bitumen expands it tends to sqeeze out and melt.
Does the sub base need to have a fall as well as the concrete?Yes. Best to keep the concrete even in thickness, as well as correct fall.
What is the minimum amount of crushed metal dust i need over the clay?
I already have tonnes of it. I wouldn't be going any less than 50mm compacted.
In my experience, not much will be saved in doing the ground works yourself unless you know it will be done correct. If it isn't done right, it may cost more for the concretor to remove the steel and redo the site works again. Have the concretor come out first and quote you for complete job and just for place and finish. You can then ask for a few tips on how the site should be prepared.

Good luck. Hope this helps.