Laying new lawn over 'difficult' ground

Hi,


I am new to gardening in general and also new to this forum. I see lots of people with great deal of experience in Gardening and landscaping on this forum so I feel I am in good hands.

We have got an old paved garden (not so much garden as it doesn’t have any grass, just stones). We want to lay some new lawn on it. It looks like historically there was a pond which previous owner have removed and filled with concrete (in small area) and builder's rubble. So we sort of know once we start to take it out what we are going to encounter.

My question is how deep we need to dig out the rubble so that we can put some top soil so we know how much topsoil to order and how bigger the skip needed for the rubble?


The area is around 40 sq. meter.


Thanks

 

Anyone ?!

 

@ric1982
I think the short answer is remove as much as possible as you need to create a smooth level seed bed. See these two earlier posts about creating lawns, one over a patio; these will give you some idea of what you need to do. New Lawn laying over where Patio Used to be! and Re-laying a small lawn - PREPARATION Question?

 

Thanks NigelJ,

Those are some useful posts. Though pictures are no longer available to see which is a shame.

So from that it looks like I need ideally 15 cm compacted topsoil before the lawn is laid ?

 

@ric1982 I would work on that, certainly not less than 10cm of topsoil. Parts of my grass go brown regularly as there are rocks within 10cm of the surface.

 

So we have started work on what we thought was a difficult task . As it tourned out, its extermely challenging one.
The pond we found in the garden is about 15 feet long , 6 feet wide and about 4 feet deep. Its filled with builders rubble, large slabs, sand etc. Plus there is a rubber liner which I think was used for pond is at the bottom of this.

Anyway, with so much digging (about 4 feet deep), we have got lot of land out. The plan is to remove all the builders rubble (excluding sand) and rubber liner and refill it with sand + small stones at the bottom (as I have got lots of it now) and top it up with sieved soil.

My question is, is there a down side to have the sand and stones at the bottom? For e.g. chance of contamination, sinking ground etc.? Should we have only small stones or only sand or both or neither ?

 

Whatever you do, it's going to sink a bit. That's just inevitable with significant amounts of digging. If you leave it a month or so after digging then the worst of it will have settled, but it'll keep moving for a while after that.

From your description, it's not impossible that what you've dug up was actually a soakaway. They used to be routinely put into gardens with the aim of helping to deal with waterlogging. You don't see them as much these days, because they didn't actually work for that - gardens which waterlog are generally either clay or have a high water table, and a soakaway is pointless for both. In places with free-draining soil though, they're often used as an alternative to connecting grey water sources (gutters, sinks, etc.) to mains sewerage. In your digging, did you check there wasn't a pipe into the "pond" which might have come from a garage roof or something?

 

Thanks

I am pretty sure its not soakaway, Neighbours told us there was a pond on this property from previous owner. (We are new owner and neighbours were here for number of years.) Also I havent found any pipes in the pond.

It is pond as I found lots of pond elements such as concerte blocks, rubber liner, GRP sheet etc. I think previous owner just got cheap and lazy with filling up the pond and just dump lots of builders rubble without properly removing the pond.

 

Hi again,

Thanks for all your suggestions last year. Unforunately due to personal reasons (health and family) I wasnt been able to complete my garden project. However due to this it looks like I am in a bigger mess then I was.

So long story short, I have removed the large rubble from the garden last year but didnt get chance to put top soil and new turf. As a result, now the garden looks like this (attached picture)!. The soil is not draining at all.

Before removing the rubble last year, the garden didnt flooded. So I think as I have removed the rubble (to make the soil more furtile) I have also remove the drainge from the soil.

This has only started to happen since mid January. Not sure why from October till mid Jan it didnt flooded.

Any thoughts how to best approach this? Really stressed!

Thanks

 

If it's anything like the soil round my way, it'll be thoroughly saturated with water by now. Early autumn was relatively dry, but then we had a load of rain culminating in flooding just before Xmas, and it's not really had a chance to dry out since. The surface might be dryish after a few days, but under the surface it's completely soaked through. So any rainfall at all, even a little bit, and it can't go anywhere except puddles.

Honestly, just sit it out. When the weather dries out, your paddling pool will dry up too, and then you can look at getting some soil in the hole.

 

Thanks @Graham B . Sound advise. Just cant bare to look at the garden.

Would just filling garden with topsoil and laying turf over it would solve the water logging issue or do I need to create trench drain like this Everything you need to know about land drains | Drainage Superstore Help & Advice ?

 

Hello ric, in answer to your question on the other thread, and this one, firstly, don't stress! Don't panic! It'll all come right I can't tell from your photo what the garden is surrounded by, whether it's other gardens, a road, whatever. You need to take into account where the water will drain to. In fact, the old pond hole sounds like an ideal place for a soakaway pit, but as Graham B says, in clay soil, the water just sits in the hole unless there's an exit trench to a point outside the garden. So have a look at the surroundings, the levels, any possible link-ups with the mains drains etc. You could perhaps have a word with the local council to see if they have a solution that involves diverting the water to a main/storm drain?

 

Originally when living in Bexhill the garden was very very wet..running water down the whole length of the garden and coming in on both sides as well because our garden was lower.. ..Being a steep hill garden it did drain off the property and down to the Lane and further down to what was woods but now housing...and the unmade Lane became tarmac and a river at heavy rain times..We did away with the soak a ways (solid clay soil .yep) and the rain water mainly went into the mains system. There was two wells one in use and that made the difference between the property being flooded or the well being filled up..was about almost 20 feet down and a couple of feet from the back door...Neighbours had filled all their wells in on our side of the Lane....bad move for Pebbles the name of the place..very fitting..When next door almost rebuilt their property the actually raised their back garden even more and that caused our wildlife pond to be receiving toxin water...their soak a ways had failed and in no uncertain terms they were informed of their lack of care over that...there was waste builders sand cement and lime in the rain flow down to ours and..yes blue murder..So all in all yours is sitting there and with all the bad weather has only increased the nightmare for you. But honestly when the rain slows it will disperse but you need then to take some preventative measure,s which you know that.....now we have only solved ours because of the terrain.. with yours it seems you need some professional assistance as drainage is the only way your going to improve this problem and I would think it can be solved ..its also getting to the reason why....maybe because the pond, having been disturbed is now acting like a sponge...I spent weeks and weeks digging out soil from the farmland next door to make part of the land drain downwards instead across on to our land.it made a lovely waterfall that then crossed the Lane into a new water course....there again sloped...feel I have not much to offer except us living in that predicament for many years.. so know what it can feel like..was always wellies until we improved it...

 

Thanks , what preventative measure do you suggest?

I was thinking about creating soakaway at the lower end of the garden with some trenches.Also dug some big holes in the garden and barry the remaning rubble and rocks. Would that suffice as preventive and perm. fix?

 

Hello again, ric. Until we know what sort of soil you've got, I really can't answer the question. When you dig down, say 18", what colour is the soil? Black, yellow, grey-blue? What's the texture like? Could you make pots with it or is it grainy? The simplest way of testing your soil (normally, not when it's already waterlogged) is to dig a 12" wide hole, 12 to 18" deep, pour a bucket of water into it and see how long it takes to drain away. Unfortunately, you won't be able to do that until it dries out!
If it's clay soil, as GrahamB said above, even a big rubble-filled hole will just fill up with water more quickly than it can naturally drain away, so not really a permanent solution. That's why I suggested looking at the possibility of channelling it into a mains or storm drain.