I have a lawn that was laid 3 weeks ago that is completely waterlogged.
Stepping on the lawn will sink 50-80mm.
The installers excavated the area by around 200-300mm and the lawn is sourrounded on all sides by a new porcelain patio. The original soil/base was quite compacted and didn't drain too well and was furthe compacted by digger and dumper running over it.
The area was topped off with top soil of around 100-120mm, levelled and then someone shuffled up and down it sides ways to compact the 100mm+ of topsoil in the afternoon and It was then turfed the next morning.
It was only watered for 3 days after the turf was laid and then hasn't been watered since. The turf has rooted in well and cannot be lifted and the grass is thriving, about 4 inches now.
Issue is, the entire are is so waterlogged that even light pressure will indent the lawn, stepping on it will leave your feet sinking 50-80mm and the soil below the turf is will run through your fingers it's that wet.
looking for advice on how to rectify this. Is it wait for it to dry out and settle and for the grass to root in deep to tie the soil together, or will the lawn always get waterlogged whenever there is heavy rains, especially through winter?
Thanks.
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If its clay it will always have this problem. Sounds like a compacted pan in the soil. Previously I've broken through the pan with a 6ft metal bar and filled the holes with sharpsand, which has helped. Then there the other options heron bone drain running to a soak or a French drains.
Thanks for the reply.
The soil isn't clay and as you say i do think it is due to the original soil being so compacted. The original area was either covered by a patio for many decades, or more recently (4 years) the patio was removed and covered in gravel, or some of it was covered in a concrete slab for the last 50 years.
The area was as I mentioned was dug out by 200-300mm to lower the entire level across the garden. The garden area isn't massive, 15m x 7m and the lawn area 8.5m x 5m.
The suggestion I have made to the installer is:
I'm not sure if the manhole will be deep enough to accomodate the land drain as they turfed over the manhole cover so I'm unable to open it up without having to try an locate the edges and cut the turf and find the handles.
Soil Below Turf after 15 days - Currently the same after 20 days
Example of Drainage after heavy rain
Laying of Lawn Area
Original Layout of Garden
Final Layout
Are you a trade or is this your own garden?
If its yours it depends on how deep your pockets are.
There is argument That rotovating can cause more soil paning.
I suggest you dig a hole as deap as you can in multiple locations to see what the problem is. It might be a case of lifting the turf and diging through the pan with a digger. Be prepared for the expense of potential rubble or even an old patio. You're never know until you dig, could be anything under there!
Thanks for the reply.
It is my own garden, I wasn't a landscaper but have been in or around the construction trade much of much of my life.
I have opened up the videos as seems like they were blocked.
if you can see the videos now, you will be able to see that we've already gone down about 400-450mm off the finished height to install the irrigation box. That area is not holding water and is filled with pea shingle so guessing the pan is not deep.
If the topsoil wasn't compacted enough and with the wet weather we've had, is it just possible that due to the topsoil not being compacted enough that it is saturated with water?
I see you're in Newbury, are you ever working up around Oxford, would be insterested in getting a professional opinion as I'm still in discussions with the company on how to get this rectified.
Thanks.
I've always compacted a lawn correctly so have not experienced your problem. In theory if not compacted correctly there would be air pockets, but still why would it not drain. There must be something deeper under there, I'm thinking an old bomb shelter or a roman mosaic floor. The only way your gonna find out is dig! Or just leave it to see if it sorts it self out.
In 15yrs of self employment ive never worked in Oxford and probably never will.
You say that the original area didn't drain well. Did you pass that information to the installers at time of quote, and request that drainage be included in the quote? If there is drainage included, then clearly it's not working, and you should get the installers to rectify. If the whole area is as bad as you say, it will never get much better without intervention, i.e dig and lay drainage over the area.
Hi Ian,
Thanks for the reply.
There area as it originally stood, gravel and concrete, always drained and I have never experienced any standing water or flodding in that area since I moved here in 2019.
The video above with the heavy rain happened while the site manager was on site and my wife commented to him in passing about it being a swimming pool, so he was aware of how well the are drained.
As for quoting for drainage, nothing was included in the quote, as it was an unknown at the time, but we did have an agreement that any chnages or additional works would be discussed and if need additional coss added to cover these.
Nothing was ever mentioned about drainage.
The lawn has probably dropped 3/4" - 1" since the 20th July, but is still a quagmire and the turf is growing exceptionally well, so much so it is about 4" long an dneeds a cut, but can't cut it as unable to step on the lawn.
To give you an idea of how wet it is, the foot prints where i did step on it have lifted out, i assume as the spoil is so wet that it is pushing upwards and lifting the turf back up where it was compressed.
I'm confused as to what is causing this.
Is it that it is not draining, as watching the video i posted above of thre rain, the area drained quite quickly, although that was the first rain for sometime, so assuming the ground was fairly dry to start with that day.
or is it that the area needs more time to settle and for the grass roots to lock all the topsoil together, and if so, is this likely to happen before the end of the growing season?
From your experience of laying lawns/turf over new topspoil, should the lawn be this wet after nearly 3 weeks, even with the rain we have had recently?
Thanks for help.
Hi RObert
How long was it watered for on those 3 days?, I would have said it should have been on a sprikler for around an hour the first day and maybe 30 mins in the evenings on subsequent days for the first week. Maybe it was left watering for hours - its amazing how much water a mains pressure hose can use.
Seperately, I agree that unless the hose was on for hours and hours on those 3 days you shouldnt have the problems you have. I can't see an easy way to explore things.. pick a corner and dig down 2 to 3 feet, see what is there, then re-assess.
Good luck
Hi Adam
i have an irrigation system installed with a Rain Bird controller
The lawn was watered for 30 mins on each zone, lawn is two zones due to water pressure and flow, 3bar and 14-16l/m and then 30 minutes the next two days, after which I stopped watering and it hasn't been watered since.
Is it likely that there is something binding the soil below the work carried out .
I worked at an old property where the rain water would start to pool when we disturbed areas in order to create new borders and beds .
First thoughts were it's heavy clay but a builder who carried out some ground work suspected it was compacted slag after being summoned to return as the area where he carried out work started to resemble a bog .
He put in plastic pipes drilled and filled with pea gravel below the surface .
The soil edging the property where we tried to create flower borders were unviable ,nothing grew and just perished .
Digging holes around there through a couple of feet of soil I hit a bed of grey chelated substance which was identified as slag .
The area was once the site of an old lead mine and a quarry , heavy rain would pool where the ground had being disturbed and couldn't run off .
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