patio- drainage?

[dendenden]

Hello all.

I wonder if those of you with more experience than I have on patio building would mind offering a bit of guidance.

I’ve removed the previous patio (the base was crumbling / slabs had become detached from the mortar), and am aiming to redo with sandstone pavers. The area is 3.5mX6m

I've gained quite a few really helpful pointers from pavingexpert.com, such as ensuring there’s adequate run off (I’ve pegged it out at 1:60) and laying the pavers on a full layer of mortar, on compressed MOT type 1.

There’s a couple of areas though that I’m unsure of.

1. At the lowest point, the patio level will be slightly below the level of the grass after accounting for the 5cm mortar + 3cm paver. Is this a concern? Should it be higher than the grass level? I’m reluctant to raise it further as this would mean a higher step near the house.
2. Do I require a drainage trench running alongside the edge of the patio to help disperse water in heavy rain? I was considering a 30cm deep / 15cm wide trench of pea gravel.
3. At the highest end of patio (running alongside the green fence) I was considering laying one row of dense blocks to the height of where the mortar layer will go, then infilling with MOT type 1. Is this acceptable?

Here's a link to some photos to help my descriptions:
http://postimg.org/gallery/17cxxge4w/

I hope that makes sense- do excuse me if these questions provoke any sighs or face-palming- any advice would be much appreciated.

Thanks, Den.

 

[r896neo]

The dense block plan is fine but obviously lay they rigid on a few inches if mortar or concrete rather than just sitting there. But I'm sure you were planning to do that anyway.

As for your grass that's a bit of a problem.
A trench a couple 450mm deep filled with free draining material would work fine assuming the ground drains ok in your garden. Ideally you want the grass lower if possible.

Often in this scenario I strip the turf back perhaps a metre and remove some soil and regrade the grass lowering the edge to met the new patio and to form a little shallow trough. If you do it gradually you don't really notice. This doesn't really work if your garden slopes towards the patio significantly.

 

[dendenden]

Thanks for the advice- I laid the blocks today on mortar and dug the trenches- good idea about striping back the turf, I may opt for this method. I'll post a pic of the finished product once it's sorted.

Thanks again, Den