Laying turf

[dmoblay]

I’ve removed an old patio. It looks like it was laid on top of another patio with patches of compacted hardcore (probably to level it out) and then under the old old patio is more hardcore and then soil. If I dig down to the original layer of conpated hardcore it would give me roughly 20mm of topsoil cover sat on top of hardcore. Is that a suitable depth of soil to lay turf, and, can I lay topsoil on top of hardcore or will it prevent drainage?

Basically does all the old hardcore need to come out as well?

[ayjay]

Hardcore should provide good drainage but 20mm of topsoil is very mean for most lawn grasses, although there may be a seed mix suitable for that, (you'd need to consult an expert). A wild flower mix is likely to be appropriate as that does requires poor soil for best effect.

[London mike 61]

Ideally 100mm of topsoil would be great because grass roots tend to only go down as far as that on a loamy/clay soil . You can lay the turf on 20mm of topsoil but it will need constant watering especially in summer and even then it may look impoverished.
If you can , give it a good layer of soil before you lay them down otherwise you will have grief going forward.

Mike

[Nos]

Don't forget green side UP!