Another back garden drainage project...

davkav

Hi guys,

I am hoping you can give me some advice with regards to drainage in my back garden.

Currently the garden is pretty soggy, so much so that if I were to drop a brick on it, it would sink about 2 inches. During the winter we have standing water on it and it is completely unusable.

Rectifying the drainage has been in the pipeline for a while now and I plan on going at it this weekend.

2 years ago I dug a hole in the centre of the garden about 2-3ft down and the soil was just heavy wet mud.

I reckon I am going to have to pull it all up and replace with good topsoil.

We are planning on doing up the garden next year (see attachment #1) with some nice stone etc. but for now I just want to get the grass drainage sorted and then I can tackle the rest of the garden next year. Don't mind the fancy fireplace etc. I was just playing around in Sketchup. The patio and walkways are probably going to go down as is in the drawing.

In attachments 2 to 4 you can see the garden as it stands today. You can also see where I removed the old decking at the weekend as it was starting to rot. It was also too big for the garden in my opinion so it was coming out anyway.

I have a number of options in mind for what to do to rectify the drainage problem.

1. Create a french drain at the far right of the garden the length of the wall and have a number of drainage pipes running from left to right of the garden and into the french drain. Remove a good chunk of the soil from the garden and put down some topsoil.
2. Create a french drain the width of the garden all the way from one side to the other, right across the middle and have some smaller drainage pipes running to it. Remove a good chunk of the soil from the garden and put down some topsoil.
3. Have no french drain but remove as much soil as financially possible and put down some rock, gravel, sand and good quality topsoil. Similar to what slowburner suggested here

With all of the above options I plan on raising the garden by about 1 or 2 inches to account for the added height of the patio once installed over the existing concrete area. (i.e. I want the grass to be level with the patio once down.) so I am hoping to use rolled turf to replace the grass.

What do you guys think? I am kind of leaning against option 2 as it would hopefully stop any future drainage issues.

I have a budget of 1000 euro. I plan on getting a skip during the week to remove the old deck wood, clear the side of the house and get as much bad soil into it as possible. I am also renting a mini excavator at the weekend to lift some old tree roots and to dig the french drain. I would like to have all materials to hand for the weekend so I can get stuck in and get it done.

Thanks in advance for any suggestions

tsuzmir

IMO option 3 makes no sense - scrap this idea. Is there an existing drainage pipe along the back wall? If so I'd run 3 or 4 french drains that would run from patio to it parallel to each other. This way you'd be removing the root of the problem. This is exactly the same problem I had: heavy clay soil was so compacted that the water would not have anywhere to escape. When I'm on a pc I'll post a link to what I've done. Might work for you as well. You could mix a bit of good soil with what you have to improve it, but I would definitely not try to remove existing soil and wholly replacing it - wouldn't make sense financially and logistically and simply it's not neccesary because top layer is not you problem, it's what underneath.

davkav

Ok so plenty has happened since my first post, apologies for not updating sooner.

In the end I ended up with a variation of option 1 and 2 outlined above due to were the stone was placed when delivered.

On the Friday of the bank holiday weekend I rented a 3/4 tonne excavator and a dumper and got stuck into removing soil from the garden.
I decided to place the soil out on the road with a plastic sheet beneath as I didn't know how much soil was going to come out of the garden.
I had lined up a man with a truck and grabber to come and collect the soil on Tuesday morning and by Tuesday evening after washing down the road you wouldn't even know that the soil had been piled there.

The plan was to dig out 6 inches of soil throughout the garden but I might have gotten a wee bit carried away in parts. The truck collecting the soil on the Tuesday had to come back for a second pick up as there was that much soil. He had said to me the first load was 19 tonnes and the truck was full for the second load so I reckon it was well over 37 tonnes of soil that came out of the garden EEK!


Anyway, once the top soil was removed a french drain about a metre deep was dug diagonally across the garden with four one foot squared trenches branching out to other parts of the garden. I laid geo textile in the base of all drains, a layer of stone, 110mm land drain pipe and then filled with stone and covered over with the geo-textile.





To date I have used 6 tonnes of 40mm drainage stone in the garden and had another 2 tonnes delivered this morning as I was short for fill for the end of the french drain closest to the house. I levelled the soil as much as I could on Saturday gone to make way for top soil that will be delivered on Friday coming.



So between now and Friday I hope complete the french drain and mark out boundary lines for where the flower beds and paths will be. I will then lay down some top soil and order the required amount of turf to lay out the new lawn. I was going to just seed the top soil but it would be nice to just wrap up the project and have a nice usable lawn for the summer.

Ill be sure to take more pictures at the weekend and post them up.

Hopefully this will cure my drainage issues.

davkav

So alot has been done in the back garden since I last updated this.

The plan was to simply order in a load of top soil, lay seed and leave it at that until after the wedding but the OH had different plans.

Patio flags were bought and the rest is history as they say.

After many many iterations of the plan for the garden we settled on this below.


So I set out into laying the flags with help from a friend of mine. Tonnes of hardcore were ordered and laid out.

Progress was slow and steady as we were only going at it on the weekends and when weather allowed.

Ill let the pictures do the talking for now.

davkav

We were not sure how well this would go. I couldn't find much information online about how people were going about cutting an inner arc.
We cut down about 2-3mm with the 9" grinder and then finished it off with the 4". The head of the 4" grinder would only go down so deep so we were left with about 2mm not cut. These simply broke off with the tap of hammer. To say we were chuffed with how well it turned out is an under statement.


As of yesterday evening my to list is as follows:
Lay the cobble around the rest of the perimeter (I've to cut a few of them to slot in under the overhang of the step at the shed)
Lift all of the items from the garden on to the patio and level the soil
Lay some plastic dividers between were the grass and flower beds will be as seen in the SketchUp drawing
Get delivery of top soil and level
Order new roll out lawn
Make new timber gates for both lane ways to 'square' off the garden

There is not much left to really, so I am hoping to have it complete in the next few weeks. It will be our little ones communion in May so I would like to have the garden usable for the day, knowing my luck it will be lashing rain though :rolleyes:

jimbev

That looks great a lot of hard I bet but worth it

MattressRick

https://www.boards.ie/discussion/comment/99659988#Comment_99659988

Hi davkav, I found these posts a few years after you did the drainage works on your garden. I need to do similar in the coming months but am unsure if it will fix it. Money is tight so it will be what you did, or astro. But I'd prefer to keep the grass.

Did your drainage work?