Drainage of flagged garden

[DIYalot]

Hi. I'm wanting to flag the entire back garden with council paving flagstones. Size about 5.5m wide 8m long.

But, there are two points of note which are very pertinent to drainage which are:

* I want the paving surface to be flat - no slope.

* All edges will abut some kind of wall (however, on 3 sides I could make "entrances" at the junction of flags and the walls to allow water to flow beyond the paving boundary.)

So, will I be able to achieve sufficient drainage given the two points above?

If not, if "entrances" at points along the boundary are insufficient, there would have to a means of allowing water to drain within the paving boundary, between the individual flag edges. That probably might not work though - unless the flags were to be raised above the soil level. That might work if there is a product for that. Not sure if there is.

Comments appreciated. Thank you.

 

[r896neo]

You need a slope of some sort for drainage otherwise water will pool and create dirty areas where it pools and damage the pointing and eventually the flags themselves.

A fall of say 1:80 will be almost un-noticable.

You need to re-think drainage. There is zero chance your entrances will provide enough soaking away for even a light shower.

40 sqm is to big an area to just hope water will find a way to escape. Do you have a gulley nearby from a rainwater downpipe for instance? Connecting in to that and then running either aco channels or a channel gulley feeding into a gulley drain might be the best bet.

The alternative would be to dig a soakaway which can go under the paving but its more work and a lot more spoil to get rid of.

 

[DIYalot]

I wonder if I could get away with a drainage slot network. The flags lay on top of the ground, but a network of drainage slots are placed between the flags. Something like as shown in the picture. There may be inexpensive plastic product offerings. Or maybe one could home-make something.

 

[r896neo]

Where will the water making its way into these slots go? Magically disappear? I will say again that the volume of water coming off 40sq/m of paving is considerable. It will not simply soakaway naturally.

The system in your picture is a stainless steel brick slot but that simply gathers the water like an aco channel and then drains it to a gulley somewhere for removal.

You need to either use a good sized soakaway buried or run to your surface water drainage system. Piping it to the nearest gulley or manhole will not be expensive, if you can post a photo or sketch layout of the paved area and your gulleys and manholes in the garden we can help.