Heavy clay drainage help

So sorry @longk i missed that! Cement mixer sounds genius, it would definitely save a lot of digging.

@shiney I was thinking, though this might just be faulty logic, that by raising the overall level it would result in any water logging happening beneath the surface, so the top layer will be fairly dry and able to be walked on without sinking etc, or is that wishful thinking?

hopefully by fixing the land drains to some degree, and adding mushroom compost and grit into the clay topsoil to improve the soil consistency will improve the drainage a lot too, but I figured raising the overall level would act like a double safeguard, if that makes sense.

 

It won't save any digging but it will make mixing the whole lot up a lot easier and quicker.

Faulty logic if your thinking of just topping up what is there. But by raising it and making it free draining all the way down to the drains means that;
1] You will not need to get rid of the displaced soil that you currently have when you mix all the grit, sand and mushroom compost in
2] It will offer some insurance against run off from the neighbours who (IIRC) you said were a bit higher than you are.

I like the idea of mushroom compost being added the more I think about it as it should encourage worm action under the lawn. Just remember, worms can't swim!

 

No thankfully there's been no flooding where I am!

Ive been looking at some photos my husband took during the job and it seems that the contractor just used regular landscaping membrane (black stuff with green striping, quite thin and holey) and not the proper construction geotextile that it says should have been used on the website paving expert.

So I went in the garden with wellies and a spade and had a little explore right at the back and there is literally over one foot of heavy clay (subsoil?) dumped on top of the drains, under the foot of clay there is that black membrane stuff, parts of it are ripped with holes in already, and there is white gravel just loose everywhere. It looks nothing like the photos on paving expert.

The garden is such a mess, after we spent literally months removing tree roots and debris and raking it level and rotovating it, it's honestly horrendously upsetting out there, though no wonder it isn't working if it hasn't been done properly. I feel sick.

Here some photos I have that my husband took of it being done. Excuse the photo quality, it was through a window. The photo of my willow, I included it because it was in October before all this so you can see how level and raked I had got the ground. Last photo is taken right now, day 4 of no rain.

 

As long as the membrane is not waterproof it is ok for the job. What puzzles me is that the only part that appears to be dug down to the level of the drainage is the herringbone pattern - is that correct?

 

Just checking because I read that it should only be non-woven construction geotextile used in land drain applications because the woven landscaping membrane doesn't filter effectively and will rapidly let clay particles ingress and block the system, and that it is weak and being buried with gravel will rip and damage the fabric, and what I saw did have rips in it.

As far as I know it is like this - a straight channel to the drain down the centre, with two branches off each side. Excuse my rubbish drawing, but like this -

 

I think you misunderstood my question. How much of the garden was dug up to the level that the drains have been laid? I appreciate that the top few centimetres have been rotavated but how much has been deep dug?

 

Oh right sorry, yes I completely misunderstood you!

Yes you are correct - None of it has been deep dug to that depth, just the drains themselves. We (me and my long-suffering husband) rotovated the entire garden ourselves, to what would be a depth of a few inches (whatever is standard depth for a petrol rotovator you push around by hand to churn to)

Then the landscaper came in with his little digger thing, dug the main trenches for the drains etc, then from what I saw he just back filled using the digger and the clay soil he had dug up to lay the drains in the first place.

The garden has just been all churned up and messed up by him driving that digger all over it while the ground was so wet.

We have been wanting to get back in there and remove the rubble, break it back up etc, but with it getting so wet and never draining since it was done, we haven't, and now I'm worried about messing with it before the landscaper has been back to look at it.

 

In Agriculture land drainage they don't use any membrane at all, just use plastic 4inch pipe with clean gravel on top then back filled with the soil that was dug out the trench and they work well

 

Thank you @Jiffy if thats right it's a big relief, I've been having horrible visions of it all needing to be ripped out and redone. It doesn't seem to be working at all though, let alone well. In fact the garden is worse and more waterlogged than it's ever been.

I find the whole situation really frustrating - and I find so much advice to be completely contradictory, I don't know what is right to do and what isn't!

Like adding sand/grit - lots of places seem to say it's pointless as you would need a ridiculously large amount to make any noticeable improvement, other places say never do it as it will compact with the clay and essentially make concrete, other places say it's brilliant and will go a long way to aiding drainage. They can't all be right?

(This is in no way aimed at anyone here, you've all been wonderful, I'm just grumpy at the whole thing and I'm not sure what to do for the best.)

 

Don't dig sand and grit in. It does indeed make it hard as concrete. Use it on top of the soil, where it will aid drainage and air circulation around the roots of your new grass.

As for the weed membrane around the drain pipe, I can't see how that could work. I used weed membrane on a patch next to my pond, then put coarse sand on top. The idea being it would be like a beach next to the pond. Sometimes if the pond is getting low, I top it up with the hose and leave it till it overflows onto my little beach. It takes hours for the water to soak through the weed membrane.

 

I may be wrong but i think youve just had a job poorly done. That site i mentioned is near gospel and I think the backfill has effectively sealed the plastic drain which will never work. There should have been a backfill of gravel with a couple inches of new topsoil to finish. Time to get photos,an experts written report and the small claims court tel number.goodluck.

 

The small claims court will expect to see evidence that you tried to find an amicable solution with the contractor first. Without that evidence, they will want to know why. If you submit a case without showing that you tried to be reasonable, then at best the case will be rejected, at worst you get listed as a 'vexatious litigant' and then you can't submit any case ever again for 3 years without having someone else, usually a lawyer, do it on your behalf.

It almost always pays to be reasonable.

Last time I had to go down this route, the person/company that ripped me off, was not reasonable. I politely told him that (in that instance) it was my legal right to either rectification of the problem, or a full refund if that was not realistically possible. He politely disagreed, so I politely said, without raising my voice, 'it's clear we both think were right but can't agree, so what I'll do is submit the case and of course I'll accept the court's judgement, whatever it may be'. The chap told me to do that, so we politely thanked each other for each others time, and that was the end of it. For approx 1 hour. Then my phone rang. As a 'good will gesture' with 'no admission of fault', they'll get the problem sorted at their expense that same day. They did so, and there were no further problems.

 

They're all sort of right. Sand and/or grit is added as it doesn't hold water. You need to chop it into the clay soil on a flat surface before adding it to the mixer along with the 'shroom compost. This is the same sort of mix (I used homemade compost) in my last garden which was thick clay and I could grow Fritillaria imperialis and F.persica without losing the bulbs over the winter to rot (this is quite hard to do even in good soil). You have to mix it well, that is the trick. If it is not well mixed it will be a waste of effort.
You don't even need to dig the whole lot out really, As you pretty much know where the drains are you can start in the middle (between two runs as it were) taking the top few centimetres off in the middle and tapering down to the drains, much like a roof and guttering works if this makes sense. What you need to do is to create a run for the water to the drains.