Heavy (REALLY heavy) clay prep for turfing?

[McHaggis]

We moved into a new build house in July and had paid the developer to lay turf. We knew it would only be for a few short months while we waited to start garden design.

We’ve now had about half the turf lifted to make way for a new deck and patio area as well as a large raised bed.

Its fair to say we’ve discovered the ground is very heavy clay. Water has been a real problem as we dug out for the new building works that have taken place.
Anyway…

The grass that is left is now in fairly ropey condition and is absolutely squelchy underfoot. We always had it in mind to lift it. Its not been laid very well and we want the ground to be properly levelled before new turf goes down.

Question is -

The clay soil is going to lead to very wet grass and probably more squelchy underfoot in winter. I need to know what the best approach us for new turfing On this clay. Do we need to dig VERY deep and replace with new topsoil before turfing? What about french drains then turf? Any ideas gratefully received. The rest of the garden works have gone really well and I’d like a nice grass area to complete the picture - flat, decent quality turf and not squelchy underfoot when it rains.

I’d welcome any advice on the prep needed for best results.

 

[cwhaley]

Unfortunately yes, you'll have to remove a layer of the clay and replace with top soil for an effective solution. I had the same problems in my non-new build home -- very squelchy on wet days. I actually raised my lawn but the principle is the same. You can have it aerated (a machine removes 'plugs' of soil) and then you can brush in sand. I did this before I raised the lawn and it helped to an extent, but really fresh soil, properly levelled and compacted down over the top made the world of difference.

Well done for choosing a real lawn, too and not plastic.

 

[Mike13]

Another slow answer to the clay problem is to dig in a suitable powdered calcium salt, slaked lime or hydrated gypsum, it will slowly deflocculate the clay. Had to do that in a previous garden and over a year or two it was noticeably less sodden through the year. Slaked lime will make it a quite alkaline soil, so not suitable for raspberries etc.