Garden drainage?

[BrokenBiker]

Hiring a mini digger this weekend to attempt to sort a long standing issue.

Our house effectively has 2 rear gardens, one at the back that is all patio, and one to the side that has a concrete path running parallel to the house a meter wide, then the rest is grass/mud

This grassy area floods like no tomorrow, holds water permanently between October and may and is starting to look like it's causing damp issues on the wall of the house on that side.

So, options to make this better? When I dug post holes for the fence last year I didn't get too deep before I hit red clay, probably about 8 inches down and the layer of clay was around a foot deep. I assume this is the bulk of my issue. I will be digging the whole area out past the clay, maybe 2 foot deep, possibly deeper.

What do I need to back fill with before soil/turf

Gravel/stone or concrete aren't an option for various reasons, mostly the dog lives in that area and the grass will offer some protection from the heat in summer and I can fit a sprinkler to keep it cool for him, but also, the Mrs wants grass so that's about as far as the conversation goes.

Area in question is 4m x 7m, minus a little bit in 1 corner

 

[6ply]

I've never had to deal with this problem (we live on elevated chalk) but I'd assume adding a free draining layer/channel will only work if there is somewhere for the surplus water to drain away, otherwise as soon as capacity has been reached you'll have surface water again.

 

[6ply]

Is the subsoil below the clay truly free draining?

 

[BrokenBiker]

Is the subsoil below the clay truly free draining?

I don't know, I haven't gotten down to it yet, but none of the other gardens around us seem to suffer.

The garden adjacent to us has grass and never seems to hold water like ours does

 

[oldbikedavey]

Something that I used to specialise in doing.
First, find your outlet....

 

[angellonewolf]

I don't know, I haven't gotten down to it yet, but none of the other gardens around us seem to suffer.

The garden adjacent to us has grass and never seems to hold water like ours does

is yours the lowest garden? hence draing all to you ?

 

[BrokenBiker]

is yours the lowest garden? hence draing all to you ?

we are in a low area, but everyone in the street is pretty level

 

[BrokenBiker]

Something that I used to specialise in doing.
First, find your outlet....

how would i do that?

 

[cocker]

You definitely would not be allowed to run a French drain into the sewer !
So I won't suggest that

 

[BrokenBiker]

You definitely would not be allowed to run a French drain into the sewer !

I'm not sure that was suggested...I'm not touching the sewer, we have enough problems with that as it is, although I will be uncovering as it runs under the edge of the path

 

[BrokenBiker]

It's getting dug out regardless of what can be done to it as the standard of mud in there at the moment is terrible...when I'm past the clay I may give it a soak down with the hose and see if it drains away in a reasonable time frame then was thinking of 20mm gravel, 10mm gravel, sand, top soil then turf but I will admit I have no ground work experience

 

[cocker]

That's Convenient , oblique junction - job jobbed !

 

[Bullet2012]

remove the patio add more grass and plants and the flooding might go away as it sounds like you almost have a swimming pool that just happens to have grass in it

 

[BrokenBiker]

remove the patio add more grass and plants and the flooding might go away as it sounds like you almost have a swimming pool that just happens to have grass in it

not an option, not only is that a much bigger project than we have time or budget for at the moment, the patio has been laid on concrete that is deeped than the foundation for the house. no idea what the previous owner was taking when they decided that was a good idea, i assume they had a contact wiht cheep concrete...or cheap meth

 

[metalmatt]

sounds like they really didn't want anyone finding out what's underneath that patio...

i guess you could excavate a big square of the grass area quite deep, install a soakaway, recover the top of it with soil & re-seed, have a french drain at the wettest part of the grass area drain into the soakaway. Lot of work though

 

[6ply]

not an option, not only is that a much bigger project than we have time or budget for at the moment, the patio has been laid on concrete that is deeped than the foundation for the house. no idea what the previous owner was taking when they decided that was a good idea, i assume they had a contact wiht cheep concrete...or cheap meth

Grab trucks for hardcore and soil are cheap if you have access. Breaking it all up could be hard work depending on the thickness.

 

[6ply]

we are in a low area, but everyone in the street is pretty level

Pretty level... But someone must be lowest.

Just out of curiosity, do your rainwater drain pipes go into a soak away?

 

[BrokenBiker]

Pretty level... But someone must be lowest.

Just out of curiosity, do your rainwater drain pipes go into a soak away?

the 2 drains in the garden both run in the sewer line. the 1 is about a foot from the soil pipe one side and man hole the other side, it has a gutter down pipe directly above it and joins directly to the side of the man hole, the soil pipe enters at the back of the man hole. the other drain is the other side of the patio, takes water from the kitchen waste pipe and gutters so rain, sink and washer, cant see exactly where it joins in but you can hear it gurgling when the sewer is unblocked and flushed through.

 

[BrokenBiker]

Grab trucks for hardcore and soil are cheap if you have access. Breaking it all up could be hard work depending on the thickness.

theres no acces to the rear garden for a truck, not really any access to the side garden as there is a thin tarmac drive and a 2.5m shed stopping a truck getting anywhere near. i have somewhere for the soil to go that i am digging out of the garden, well most of it anyway

 

[BrokenBiker]

It has also just occured to me...there is a section of soil covered with gravel at the front of the house that doesn't flood, and a section right at the back of the patio that doesn't flood, same soil and gravel.