Seeding a new lawn

What the chap recommended is similar to creating a tee or a sports ground where drainage is important. Obviously with a sports created foundation it will be made of layers so you don’t need to do this for lawn.
The idea of adding a sand mixed soil base to the foundation is to allow drainage but it depends on the depth of the drainage subsoil content. There is no harm in doing what he suggested but you must insure you have at least 150mm of topsoil on top.
With regarding the covering of seeds the golden rule is the larger the seed the deeper it can be buried so it depends on the variety of seed that you’re doing but the best advice is to simply cover the seed with around 5 mm of soil. That covers most seeds used but you can go deeper but if you stick to that depth or near about it will be fine.
Your other consideration when you are applying topsoil is what is the soil up against i.e. a fence or brickwork. You should consider whether the soil will impact any of the surrounding area so for example you don’t want to go higher up against a fence with soil as that will just aid the rotting process.
I think you will find this will take you longer than expected, don’t take shortcuts and you need to make sure that the soil is firm but not compacted By working at it. If it’s compacted too hard you’ll get drainage issues and poor growth and if it’s too soft it will sink and become very lumpy.
The biggest mistake made with soil calculations is that the calculation does not take into account the fall from the soil when prepared so pays to have a little extra soil to play with.
If example your base or the subsoil content is heavy clay then I’m afraid if you were to add the sand mix on top of this subsoil content and then add your topsoil on top of the sand mix the clay subsoil would remain the same.
The trouble with aerating the subsoil content as you don’t know the depth so you could punch holes till the cows come home and it will make very little difference. Normally if drainage was a real issue you would have to think about a drainage system under the lawn which is going to cost a lot more.
Why don’t you try posting a picture so members can see what you’re up against.

 

Hmmm. Not sure what to do with the 70:30 top dressing then to be honest. The lawn guy suggested aerating it first with a solid tine but without this machine he said that forking it would also work. You’re suggesting not to do this though by the sounds of it?

If I don’t do this then what do I do with the tonne of top dressing that I’ve bought?

No problem with achieving a good layer of top soil as I’ve ordered 2 tonne of that so it should be plenty to drop down, get level, walk on and they search up prior to seeding. Finally adding a 5mm layer of top soil on over the seed should also be fine.

Trying to get photos but as I don’t live near him it’s not easy. We’re starting at 12 today so I’m now getting a bit worried that I’m not going to be doing the right thing. I’m just trying to help out a friend who is trying to get a bit of grass for his family and son to enjoy. Feels like the can of worms has now been opened. Thanks for your help/advice guys.

 

Managed to get him to send me some photos through

It’s just the cleared area that being done as the remaining (weed) part is intended for a patio area.

Hope these photos help.

 

That’s better thanks.
The lawn guy should have pointed out compaction but looking at your photos it looks better than I was expecting.
Couple of problems.
Notice the fence, if you add soil it will start to cover the gravel boards/fence posts and they will soon rot.
Notice the property, take note of the DPC layer.
Are you planning on seeding right to the brick wall?

 

That looks ok to me soil-wise. I'd put the top-dressing by, for another day.

Your main problem is that it looks like you've still got weeds in there. You could do with digging them out or spraying them, before you put anything over the top of them.

 

Perfect, thanks.

The bit with the weeds in is being saved for patio space. Yes it’ll be into the gravel boards so I guess a plan would be to cut a small strip out around the edge next year and fill it with gravel to help prolong the life of the boards.

Going to use some of the top dressing to go into some of the holes/cracks and then hit it with the top soil.

I’ve covered the whole lot with weedol lawn weed killer so hope that will suppress the small amount that are currently there.

Thanks for your advice.

 

Wow 2 tonne of top soil doesn’t go very far does it! Will be needing another 3 tonne delivering and to hit it again. Crikey it’s been hard work! Knew it would.

 

I think you should have done the patio first then once completed the lawn can be sorted. That way you will not end up spending time sorting out the damage to the lawn after you have created the patio because you are going to need to do a fair bit of work on the patio area.

 

Patio is due in a year or twos time and they have a family that need somewhere to play. So hopefully this’ll given them a lawn they can use. That’s the plan anyway.