Advice of patio foundations

[Adam_R]

Hi All

I hope you are all well, during lockdown the wife has had a fantastic idea to rejuvenate our garden, more specifically extend our patio! 

 

Currently the raised patio is 4.9m wide, 3.7m long, 0. 18-0.2m elevated from ground level and is clad in the most beautiful pink concrete tiles in standard 600x600 mm. 

The idea is that we I extend the patio to 9.1m wide x 5.4m long, which equates to the full width and another 1.8m in to the garden. The idea is to strip off the current slabs pink slabs and relay porcelain tiles over the  whole new area to give us a much smarter look. 

The idea of extending the patio, apart from enhancing the look of the garden and giving us more hard area to put chimnea, bbq and seating is to also have a 10 foot pool sat on top of it in the warmer months for the children to play in. Previously this was situated on the grass but left a lovely dead patch in the lawn. 

Now some quick sums tell me that this is going to be around 4 tonnes of water sat over a 10 foot ft circle.. I certainly don't want the new patio to move! 

 

Initial idea for the construction was:

- Dig a 60cm deep trench (200mm wide) around the perimeter of the new patio, pour and level a concrete foundation for the retaining wall

- Build up from the foundation up to the correct height using brick and mortar, maybe with a breeze block secondary layer if required? 

- fill in the empty new area with the excess soil dug for the foundations and the pink slabs from the existing patio

 

Then I'm at a slight loss as to what to do to make sure this is robust enough for the pool, do I fill with hardcore and then top with a thick layer of sand and use a compactor? Or should I mix and pour concrete in to the space? I don't have a cement mixer so would have to either rent one or mix by spade and wheelbarrow. 

 

Thanks for your help! 

[tonyshouse]

What is the make-up under the existing patio? 
 

I would hesitate at filling with soil, well compacted would be ok, that is not easy to achieve and needs lower no organic

 

i would do 150 or at a pinch 125 thick reinforced slab with A252 mesh that way it would move as one, also need to have a movement joint between new and existing and don’t put the pool across this 

 

[Adam_R]

Hi Tony

 

Thanks for your response. 

Currently have no idea what the makeup of the current patio slab is.. Would this be beneficial to know before I get too carried away? 

Good idea about a reinforced mesh, from the sounds of it it may be worth calculating the amount of concrete required and getting it made and delivered to site.. Only issue is access and the back garden isn't easy and It would take a number of trips with a wheelbarrow. 

[Mr Punter]

Have a look at https://www.pavingexpert.com/ceramic_01

 

If you are having a pool, make sure the paving is non-slip.