Replacing Paving with Turf/Lawn - Ground Prep

[sport1901966]

Hi All,

This is my first post to DIYnot. My girlfriend and I have just bought our first property. For the most part its in fairly good condition, just tatty and in need of a bit of an update. Some of our biggest tasks will be some addition of power sockets and light switches, relocation of a radiator and repair/replacement of floor boards. However the first one to be tackled, and the subject of this post, is the garden.

When we bought it it had no grass, just a keyhole shaped patio with plant boarders, and a raised section at the back overgrown with bushes. I have since laid a slab base and build a shed on the raised section (using slabs from the patio) and the next step is to clear the rest of the patio and lay down turf, leaving some slim borders down each side of the garden.



I have started raising the patio, and the slabs have been laid on what seems to be a mix of small ballast stones, sharp sand and dry cement. Clearly not ideal for supporting the growth of grass.





I have quite a large amount of soil that was moved when levelling for the shed base, the piles can be seen in the first picture, to the right of the shed, and under the tree on the left.

My question is, based on experience, what do I need to do to prepare the ground for laying turf? I want to lay about 45m^2 of grass and imagine a fair amount of levelling will be required, especially if a large amount of clearing is required from underneath the patio. Will this require purchase of more topsoil, should I buy some form of fertilizer to mix in etc. I'm very comfortable with DIY but gardens are not something I have any experience of! Any and all help is appreciated.

This is a rough idea of the intended final result -



PS: If anyone wants any crazy paving in the herts area - its all up for grabs providing you can collect!

 

[sport1901966]

I got some more time yesterday evening to clear the patio further and see what I will be working with:



My plan is to

1) Dig out all the sand/concrete/stone pebble mix - how critical is it to get all of this out?
2) Level the ground as much as possible
3) Add some topsoil to help with leveling - I am thinking one bulk bag will be enough? (hallstone 600litre - http://www.rolawndirect.co.uk/products-topsoil-hallstone_topsoil.html)
4) Rotavate the ground
5) Rake to give a fine tilth
6) Tread down
7) Lay turf

Does anyone have any suggestions criticisms to this plan?

 

[lasors]

It depends how much you want to spend, and conversely how much donkey work you're willing to do, and what quality of finish you want. I've just done our garden on our first home and while it takes time and it's bloody hard work it is rewarding. This involved something similar to you, removing a slabbed area and a huge area of pebbles laid on soil, turning it all over, importing soil and laying turf. It's a big effort to dig over every inch, removing large stones/bricks/concrete, but digging relieves compaction and aerates the soil and it will allow your turf a much healthier start.

Try and get rid of as much of the mortar and hardcore under the patio as you can, too much stone and sand isn't the best foundation for turf. The surrounding soil looks like it has been flower beds so the soil may be ok so you should be able to avoid digging it out and replacing it all, so blending it with a known good quality topsoil would improve it without going to the effort and expense of replacing it all with good soil. The Rolawn blended loam is expensive but it is very nice and very nutritious.

Your type of soil may dictate another path, though. If you have a lot of clay under the surface this may not be ideal. Have a look if you don't already know. To replace your soil to a depth of 2 inches would mean 4 bags of the Hallstone you mentioned, to cover 45sqm.

Blend in the topsoil with a rotavator, as you have suggested. Get as fine a tilth as you can manage and rake and tread to level. Use a wide landscaping rake - yellow plastic ones on ebay (sold minus handle) are good and cheap.

We used Rolawn turf which I found to be excellent quality. Laid it at the height of the heatwave, watered well, and it's thriving.

 

[r896neo]

Lasors advice is good.

Turf is very resiliant and will grow almost on almost anything. its more a case of how well you want to do it.

In an ideal world you want a good 4 inches of good topsoil and as lasors said relieving compaction will massively help soil structure and drainage which are both important.

feeding turf with fertilizer is easy and can be done once its laid. The soil structure is the bit you can't improve once its laid so consider adding some grit too if the ground is heavy and poor drainage.

Large stones or rocks should come out but gravel is not a problem as long as there is not loads of it.

 

[lasors]

Regarding fertiliser, a pre turf fertiliser is a good bet and will promote rapid root growth. I used B&Q's own brand, Verve, and I'm sure it helped. The new lawn is very green and is growing quickly with roots of 1 inch in a week.

 

[r896neo]

Apologies i wasn't implying a pre-turfing fertiliser was not a good idea, It most certainly is.

I was just trying to highlight the need to prioritise spending your efforts and money on things that can't be sorted out post laying.

 

[lasors]

Oh I realise that, it's just if I were to fertilise at all I'd spend the money on pre turf stuff to give the soil immediate and direct nourishment for the turf roots. Depending on when it gets laid this might be more important, particularly if towards end of season and the soil is a bit poor. It won't then need anything else for 6 months, or longer in fact, to the beginning of next season.

It's easy to do in granular form, when it's all raked and level just throw it down and water it in a little and lay the turf on top.

 

[sport1901966]

Wow, thanks to you both for taking the time to give such in depth advice. I've always been an advocate of the 'buy cheap, buy twice' and 'do a job properly and do it once' philosophy's. However I am also wary of the fact that a lot of people like to advise as though the only way to do things is to spend an excessive amount and work unnecessarily hard to achieve a standard that is far beyond what is more than good enough.

Based in your advice it sounds like we are on the right track. We made a start today and so far have turned over the majority of the area by hand and cleared all the big debris. Unfortunately there are a seemingly infinite amount of small stones (1 inch) or less that area going to be nigh on impossible to remove, I'd say the composition is roughly 45:55 stone to sand/soil. Also there does seem to be some clay content, but I'm hoping that the sand used to lay the paving may be sufficient to aid drainage, is this a fair assumption?

To give you an idea this is how it looks as of this evening:



And a close up of the turned over/ cleared as much as possible soil:



As it happens I have ordered 2 bulk bags of the Rolawn blended loam, hopefully this will be enough to offset the stone contend do you think?

Our plan now is to rotavate the ground as much as possible, and as you suggest, bring in the soil from the flower beds to the previously paved area to help with the levelling and soil composition, once this is rotavted together we'll bring in the first bag of topsoil and rotavate that in to get a more consistent mix, then bring in the 2nd bag and rake to a tilth to give a good layer for the turf to take to. We were thinking of hiring a petrol powered whacker to compact the soil at this stage before laying the turf, or will this be too much compaction?

I like the idea of the pre-fertilisation, because of the stone content I think it will be good idea to help the turf as much as possible.

How does this plan of action sound?

Thanks again for all the advice, I am enjoying learning all these new skills!

 

[lasors]

Sounds good, but don't bother with a wacker, it's a bad idea and will only undo the work you've done digging over to aid aeration. Compacting it could cause you drainage problems as well. Repeated raking and heeling (walking on your heels, feet together like a penguin) is the best way to level and apply just the right amount of compaction to remove air pockets near the surface and help prevent settlement.

Don't worry about the stones you have left, under one inch, spread around enough, won't give you any problems.

Digging in one lot of topsoil and topping off with the other is good.

If you're keeping your shrubs in a wavy edged border up the sides just lay the turf as it comes, leaving a square jagged edge. Wait until it has established then cut your edges with a cheap bread knife.

 

[lasors]

Some inspiration for you?

My first attempt at any major landscaping work, and the first time I've done any paving as well. Considering this, I'm very happy with the result. I was aiming for a fairly low maintenance garden with patio areas to sit in the sun, some vegetable beds for a bit of growing fun and lawn for our little boy to run around on.

First photo before I started the majority of the work. It was worse than this, but it's the earliest photo I can find to hand. There was slabs down the right, pebbles on soil near the bottom, and brambles 8ft high and 8ft deep hiding the back fence. See the wire mesh cylinder on the right? It's mesh inside bicycle wheels, used to sieve a lot of soil to remove stones for the skip without wasting all the soil. You can just see the awful old council slab patio in the foreground. They were laid on soil and clinker of course, which all came out, and had shifted all over the place and was a right mess. No digger access so everything has been done with a spade!



Top patio started, majority of old turf removed but no major digging over yet...



Bottom patio foundation in and shed going up on slab base...



Bottom patio done, with raised beds for some vege fun. Lawn area has been dug over to a depth of 6inches, large stones and roots removed. It was hard work to dig because it's thick with clay which, in the very hot weather we had, baked it rock hard. The plus side was as it was so dry, once dug up it broke down easily for raking. You can see areas of sand and gravel from the concrete and mortar etc that was mixed for the patios. This was just spread around as much as possible so it was a thin layer and not inches deep with sand. Oh and top patio down, minus jointing.



Good quality blended topsoil spread and levelled on top. Depth of 2-3 inches. This isn't Rolawn's stuff but is similar stuff I have used before from a local landscape garden centre. White grit is the pre-turf fertiliser, thrown down by hand...



Lawn down, working off boards. Sprinkler going already, 28degrees that day...



First cut last Thursday. Needs another one now but it's a bit wet today...



Aaaaaaaaaand.... enjoy!

 

[sport1901966]

Very impressive work, got a high standard to aim for now!

Thought I'd post up an update of the progress. Things were all going very well as we got to Monday afternoon. By that stage we had managed to turn all the patio base and rake out as many stones as possible. Once the surrounding flower beds were turned in with it using a rotavator (superb tool!) and leveled things were starting to look much better. As I had a load of soil left over from creating the shed base we also used this to improve the soil composition of the area to be leveled and turfed. This did such a good job that we reduced the soil order down to a single bag.

As we moved towards the house however the soil composition was terrible, the more we turned it over the more bricks, stones and large blocks of concrete we began to find all bound together with thick sticky clay. We eventually cleared the majority and were left with quite a large hole - probably went down a foot in places.

However the real troubles began when the rain started. The soil became unrakeable and we had to call time. When I woke up Tuesday it was raining, and continued to do so until about 3pm. It meant absolutely nothing could be done regarding leveling, but worse still the bad soil near the house was showing big drainage issues. We rotavated in two bags of sand and two of top soil but they made very little difference (I have since found through research that organic matter is much better for improving drainage). By this point it had become more or less a bog and we had to call it a day, unfortunately it was too late to cancel the turf which was due the following morning (bringing us to today).




Today I bought a load of farmyard manure/organic matter from homebase and rotavated that into the boggy area and it did make a big improvement (considering how bad it was initially) along with a couple of wheelbarrows of drier soil from the raised section of the garden (not being turfed) it was brought to a much better level, and was starting to become much less saturated with water. Unfortunately the turf was delivered around 10:30am and the only choice we have had is to temporarily unroll what we can in areas not needing leveling, and keep that well watered, along with the remaining rolled up turf. It seems to be holding up well so far. The plan now is to hope the predicted return of the 'heatwave' will dry out the soil sufficiently to be leveled as quickly as possible (touch wood), and keep the soil as moist as possible until it can be laid. That just about brings us up to date, here is how things looked when we stopped this evening -





Sorry for the long winded post!

 

[lasors]

Good effort, it's looking much better.

Might be a bit late but try not to water the turf too much when still rolled up as not only will you wash the soil out and thin the rolls you'll speed up the rotting of the turf which started the moment it was harvested.

As you have found wet soil is very difficult to work, especially when it has a high clay content. If this has happened when I did ours I'd have given up! Not much you can do but let it dry out as much as possible and do your best to level it and. remove air pockets.

Good luck today (nice warm, dry weather at least!) and keep us posted.

 

[sport1901966]

Thanks for the words of encouragement lasors, its been a day of hard work in some intense heat!

The soil was drying out, but for it to have reached the stage where it would crumble down to a nice rakeable tilth I think would have taken days. We left it until late afternoon, periodically breaking it down by hand with rakes but it wasn't ever going to reach a condition near ideal today, and as the turf had been delivered we had to work with what we'd got. To that end we did the heel compacting as much as possible to firm things up, and filled any obvious dips, although it was very hard to pick out uneven areas/ruts due to the 'clumpy' consistency and variation of colour. It was then time to bring through the top soil and rake it over, 1 bulk bag was easily enough to give perfectly reasonable coverage, a second may have been ideal, but I felt largely unnecessary. Due to the slight unevenness of the lower soil I decided the best option was to compact and level with a short length of wood, as I was laying the turf. This method seems to have been reasonably successful, although it is still far from perfect. Anyway, I'll stop rambling on and put up a couple of pics! Thanks for all the advice everyone.

..Just one last question, how 'wet' should I be getting it when watering in the morning/evenings - I was thinking 10mins with the sprinkler each time?

 

[r896neo]

No try to water deeply for a longer period. An hour every other day is much better than 15 mins every night.

It is not possible to over water turf.

You can over water seed and damage it but not turf so go nuts.

 

[sport1901966]

Thanks for the speedy reply.

Thats good to know, i'll be very generous then!