A mammoth task for a total novice!

Hi folks,

I've just built myself a house and have come here looking for whatever helpful advice may be on offer. I'm totally new to any kind of gardening but am planning a rather large building site surrounding my house in to a lovely garden. I've decided to start with the smallish area at the back of my house. I hired a mini-excavator last weekend and this was the result:

The idea is that I'm going to lay a further two rows of paving slabs outside the path to create a patio area running the entire length of the house. I also want to put up a small retaining wall along the edge of the patio with steps going up to a lawn which will be levelled off as much as easily achievable.

As you can see from the photo the soil is wet! It has been raining a lot lately but in Orkney that's no great surprise. What isn't so obvious from the photo is that there is a lot of clay in the soil and it is retaining all the water that is there.

I guess my first question would be for anyone who has laid a patio before. Do I need to put down a base of hardcore or can I just spread out a dry mix of sand and cement to lay the slabs on? How deep will I need to go still to lay the slabs?

The next question I would ask is about the foundations for my retaining wall. I think the wall will only be 2-3 feet high and I intend to make it out of 6" concrete blocks laid on the flat. How deep and wide should I dig the foundations? Again, will I need a hardcore base?

I hope there are some patient souls among you because I am completely new to all this and will be learning as I do pretty much.

Thanks for reading though. I look forward to speaking to as many of you as possible.

Cheers,

Kev

 

A layer of hardcore is a definite for stability and rigidity. Needs to be about 4" deep. The base of your retaining wall should be 4" wider than the wall fore and aft. The larger and deeper the better, you don't want to spend your years in your house slowly watching the wall coming towards the house and having to re-do it. Best wishes in the house. Cheers, Tony.

 

Welome to GC Kev

I am new to gardening too, so am unable to give authorotive advice, though looking at the pic, if that is where you are laying the additional slabs to make a patio, you can see it is not draining away, so unless you do something to provide a soak, you will always have a small swimming pool on your patio?

Klefti has given you the main advice, though the heavy guns who knowthe rest will assist you shortly, I think you need to make a soak away below the hardcore
or possibly along the edge before your retaining wall

As I say I do not know, just posting so you see your posts are read on here, and will be answered, When others get time off for good behaviour

Jack McHammocklashing

 

I'm no builder, but I did my own patio last year. I put down about 4 inches of hardcore for a foundation, then mixed up cement, and sat the stones on the cement. I didn't go for a dry mix, partly acting on advice of people wiser than me, and partly because I've seen patios that are just a few years old that were laid onto nothing more than a dry mix. They end up with more lumps and bumps than a lumpy bumpy thing.

I can offer no advice about your retaining wall, as I expect even at just 3ft high, its got to hold back hundreds of tonnes of clay, and clay moves when its wet. There are plenty of knowledgeable folks on here who'll be able to advise about that.

You mentioned you are going to lay a lawn once you've levelled the area as well as you can. I'd suggest that you put a lot more effort into ground preparation than I did with mine. You're supposed to enrich the soil, and whack it down with a whacker before seeding/turfing. I didn't, now I have the ongoing requirement to top dress more than ought to be the case as I try to iron out the lumps and bumps that resulted from the soil settling after I'd levelled and seeded it.

 

Thanks to you all for the advice so far. Was out for a bit in the garden at the weekend so I've made a few more discoveries and had another couple of ideas.

Firstly, it turns out there is already hardcore under the area I've excavated. I'd completely forgotten but the builder had the hardcore around the house a lot wider than required for putting the scaffolding on. It's only about an inch or two below the surface soil now. This makes it slightly more worrying that it's not draining.

Speaking of draining, one of the ideas I did have was to slope the patio slightly towards the house. We have a soakaway in to the surface drains going all the way around so I'm guessing this would be sufficient to clear any water on the patio. Most websites I've visited say that you should slope your patio away from the house but surely that must only be if the slabs touch the walls of the house?

One problem with the existing hardcore is that it's now going to be a nightmare to get down far enough to dig the founds for the retaining wall. I'll just have to see how it goes. I've ordered the slabs for delivery today along with 10 bags of cement. I already have tonne bag of sand so hopefully that'll do me for a bit. I nearly wish I had the money to just pay someone to do this for me as I did with the house but it's about time I got my hands dirty. I'll feel much more satisfied in the long run!!

 

Well, I've been quite busy since my last post and am fairly pleased with the results so far. I've laid most of the second row of slabs. I still have to work out how best to lay over the rodding points which you can see in the bottom of the picture below.

I'm going to hold off on the third row of slabs until I get the found for my retaining wall dug out. I've already taken the trench down about 6-10 inches but intend to do another few inches just to make sure. It's hard going but it feels quite rewarding. The picture was taken before I started digging the found by the way in case any of you are squinting trying to see it! Basically I'm digging out between the red line and the bank.

One problem I'm having at the moment is the soil itself has become very sticky red clay which is full of stones. Doesn't make digging easy and doesn't drain very well. As the weather has taken a turn for the worse I think I may need to pour the concrete in the found as soon as possible before the whole thing collapses in on itself and I have to do all the digging again! Not a pleasant thought.

Kev

 

You have been busy - looking good

Don't know what rodding points are but you could leave a gap where they are, make a feature of it and plant a nice shrub which will grow to cover them but which could easily be pruned to size.

 

Thanks for the reply merleworld.

The rodding points are just access points to the waste water and surface water drains which are set at an angle to 'rod' them clear in the event of a blockage as far as I know. I have them at each point the underground pipes change direction. I will be cutting them down lower so they're not sticking up like that but I don't know whether to cut a notch out of the slab and then screed around them with cement or whether I should cut them down a bit further and replace the cut section of slab loosely on the top so access can still be gained. Any other ideas would be most welcome.

 

Cut the 4" pipe down so the rodding eye is flush with level of the slabs,also when doing the retaining wall think about putting some weep holes to release some of the ground water.
you posted whilst i was replying cut the slab out around the eyes and just tidy up with a screed to much it will crack and look untidy

 

That's a good idea - you could put a slab down over the top or a recess tray cover like these

No idea how much they cost mind!

 

Rather than put weep holes in the wall I was intending to run a perforated pipe down the back of it, connected to the surface water drain which would then be covered in chips. This should hopefully drain any water likely to build up at the back of the wall.

I'm not sure what you mean with your next comment though. Do you mean that I shouldn't use too much screed because it will crack or that I shouldn't cut too much out of the slab because it will crack?

Cheers!

 

That could be a solution indeed. I wonder if it would be a bit of overkill though since it's only about a 4" pipe. I'll have to look in to them to see how small they come.

Cheers!

 

That looks really good JWK! That's pretty much what I was thinking of doing but I'll admit the thing which was putting me off was the thought that it would be wobbly underfoot where the rest of the patio was solid. Seems like a good solution and potentially a winner!

Cheers!