New lawn on top of old one

pramsay13

We have a lawn that is not in great condition after building work.
We are wanting to raise the level of the grass by around 5 - 10cm.
Can we just out down a layer of compost and then lay new turf on top?

twopenny

That would be a lot of compost. I;m not sure that turf would enjoy being on so much loose stuff.

I'd be inclined to get top soil. Builders merchants stock it at very good prices. It's not the best for flower/veg beds but should be fine for turf.

You're going to need a lot of treading down to get it nice and firm. Also level.

Davesnave

Compost isn't the right medium for growing a lawn. If the current lawn is draining OK, you can raise the level with top soil from a reputable supplier as twopenny says. At additional cost you can get sterilised soil with no viable weed seeds in it.

Treading down and/or rolling will be necessary as newly spread soil will take time to settle. You may  need tonnes of the stuff to raise a lawn by 10cm, but obviously that depends on its size.

shinytop

You should remove the old turf.  5-10cm of topsoil (and it will be topsoil you need not compost) on an old, compacted lawn isn't much.  Any ups and downs will just be repeated and some weeds might grow through. I just did some of mine. I took off the top layer with a mattock and spread about 5cm of topsoil.  I compacted it with a hand tamper/rammer before and after and it looks great.  Topsoil is about £65-70 a builder's bag delivered.  

twopenny

Another thought. If you still want the full 10cm it would be best to put half down first and firm it down. Then do the same with the next half.

This describes the process well and why including leveling. Each site I looked at said remove weeds first.

https://blog.fantasticservices.com/how-to-level-soil-before-laying-turf/