Building a patio

[Grahamm]

A question for the FOC-U font of all knowledge...

My garden is basically an adventure playground for cats at the moment, but it's causing problems for my gf as the grass pollen kicks off her hay fever.

So I'm looking to replace it with a patio.

The idea is to hire a mini-digger, dig it out, put in a weed-proof barrier, then a couple of layers of hard core, tamp them down with a Wacka Plate, add a layer of sharp sand, then lay the patio on top of that, allowing a 1:60 drop for drainage (there'll be a strip of earth at the side for water to drain into.

Has anyone on here done this sort of job and has any useful suggestions, comments or recommendations for anything I might have missed?

[fazersharp]

Sounds like you should be the one advising others. 

I would just say use hardcore mot type 1. And don't underestimate how much earth it takes to fill a skip, when you dig it out it magically triples in volume.

[agricola]

A question for the FOC-U font of all knowledge...

My garden is basically an adventure playground for cats at the moment, but it's causing problems for my gf as the grass pollen kicks off her hay fever.

So I'm looking to replace it with a patio.

The idea is to hire a mini-digger, dig it out, put in a weed-proof barrier, then a couple of layers of hard core, tamp them down with a Wacka Plate, add a layer of sharp sand, then lay the patio on top of that, allowing a 1:60 drop for drainage (there'll be a strip of earth at the side for water to drain into.

Has anyone on here done this sort of job and has any useful suggestions, comments or recommendations for anything I might have missed?

If youre layin slabs of any description, my advice would be to lay them on a full bed of mortar with mortar joints, or youre likely to be plagued with billions of foccin ants every summer getting between the joints and nesting, and when they start to fly its like a black cloud.

[Grahamm]

Sounds like you should be the one advising others. 

We've looked at various online guides and this is the one we're following: https://www.marshalls.co.uk/gardens-and-driveways/blog/how-do-i-lay-a-patio-on-sand

I would just say use hardcore mot type 1.

Yes, that appears to be what's generally recommended.

And don't underestimate how much earth it takes to fill a skip, when you dig it out it magically triples in volume.

We're actually going for Skip Bags because of access issues, but we're also hiring a mini dumper because it'll be about 7.5 tonnes of earth to remove and then a similar weight of hardcore etc to get back in, plus the sand and paving slabs.

The bit we found most amusing is that the cost of hiring a digger and dumper for a week is only about twice the cost of hiring them for a day!

[Grahamm]

If youre layin slabs of any description, my advice would be to lay them on a full bed of mortar with mortar joints, or youre likely to be plagued with billions of foccin ants every summer getting between the joints and nesting, and when they start to fly its like a black cloud.

Thanks for the suggestion, but there's going to be a narrow flower bed along the edge where it runs alongside the garden wall, so they'd just get through that anyway!

Also cement/ mortar adds another level of complexity which we'd prefer to avoid if at all possible.

[fazersharp]

My experience with sharp halls south terrace is that in order to have any chance of the cement between slabs lasting and not coming out from freezing  and movement is that you have to put it in wet and not dry dust. You also have to actually have a big enough gap to get it down there.
Then you have the problem of making a mess of the top of the next slab.
Its OCD but I mask the edges with bodge tape on the slab, keeps it clean. I also mix waterproofer in the mix and my latest experiment last year was to add fibre glass strands to the mix and then paint on tile grout waterproofer /sealer painstakingly along every join.
So apart from that I would recommend a slab that has very straight smooth edges so that you can but them up tightly without any gaps at all between them, stops ants and weeds.
Another one on weeds is no matter what barrier you have under ~ the weeds will take hold from above.


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[fazersharp]

Good info here.
https://www.pavingexpert.com/layflag1




https://www.pavingexpert.com/patio01

[fazersharp]

and another thing. You will need an angle grinder to cut some slabs. Do yourself and your neighbours a favour and hire a water fed one.
Have you thought about astro turf for a section of the area.

[robby boy]

Depending how big an area you are covering I would use 2x2 slabs. if its a big area 3x2's will cover it quicker but they are heavy and hard on your back if your not used to handling them.

[Grahamm]

and another thing. You will need an angle grinder to cut some slabs.

We're going for the  type of paving that has sections of different sizes (eg https://www.pavingsuperstore.co.uk/garden-paving/garden-paving-and-pathway/garden-paving-slabs-and-flags/global-stone-paving-riven-sandstone-castle-grey-pure-grey-paving-slabs.html ) and my gf is an absolute whizz at jigsaws, so we shouldn't have any problems with needing to cut slabs

Have you thought about astro turf for a section of the area.

There is a house nearby that has astroturf [insert Throwing Up emoticon here...!]

One concern that did come to mind this evening is that, as mentioned, there's going to be a narrow strip of earth alongside the wall which is where the water from the patio will drain off.

We were going to use it as a sort of flower bed to grow some sort of climbing plant as we're going to put a trellis on the (waist high) wall to give a little more shade/ privacy.

I was just wondering if that will be enough if it absolutely buckets down or whether it would get totally water logged because there won't be enough drainage.

Do you have any idea about this?

[BBROWN1664]

Ideally you should put a drainage chanel in if it is a big patio so it doesnt flood the flowerbed area and undermine any walls. Somethign like a french drain taking it back under the patio would work.

[Gnasher]

I laid my mothers patio, 25yrs ago using slabs think they were Marshall, can't remember.  It's still in good condition, no subsidence, loose or cracked slabs, ice damage or loose/missing grouting.

As with most things it's all in the prep, the materials used and what you're laying on, i.e. clay, earth etc.  Her ground was stable earth, I dug out the top soil to a depth (all approx) of 200mm, 100mm of (I used brick as I'd knocked down a wall hence the thickness) compacted hard core.  Using pegged string marked out the finished height which is sloping away an to one corner.  Using a mixer I mixed concrete and laid it in slab size lumps 50mm thick, laying each slab in turn, with a 10mm gap, leveling to the string.  I made sure there was no gaps between each lump of concrete, this stops water ingress and ants     Left it 24hrs, the gourting/pointing call it what you will, slight damp pointing cement mix, it must just be damp, so as it won't stick/hold together if you squeeze it in your hand.  Lay the mix along the slab gaps and work the mix in using a pointing tool, make sure it's pushed well in, finish off the surface in the normal pointing (go for grooved helps drain water) manner, once complete sweep off the unused mix  Depending on the size of your patio you may have to point/sweep in sections.  Once sweeped using a sponge wash each slab to remove unset cement.

Left it another 24hrs, job done.  You could use stone chippings as hard core and the base would be thinner, I used broken brick as I had it to hand.  As mentioned 25yrs and it's still as good as new.


 

[mtread]

I've been using this for jointing between the slabs.
www.screwfix.com/silka


Permeable, but resistant to weeds, ants and does not shrink apparently. Seems to be a resin/coarse sand product. Would be expensive for a very large area.


Working very well so far, but it's only 4 weeks in 

[fazersharp]

I've been using this for jointing between the slabs.
www.screwfix.com/silka


Permeable, but resistant to weeds, ants and does not shrink apparently. Seems to be a resin/coarse sand product. Would be expensive for a very large area.


Working very well so far, but it's only 4 weeks in 

I have never been brave enough to use those two part resins as they are so expensive - and then find that they are not actually very good.

[Grahamm]

Ideally you should put a drainage chanel in if it is a big patio so it doesnt flood the flowerbed area and undermine any walls. Somethign like a french drain taking it back under the patio would work.

Here's a picture of the view from my upstairs back window and a diagram of what I'm aiming for.

There are actually two separate sections, with a concrete path down the middle. I think orginally the one on the right was a lawn and the other a flower bed, but, since I have no interest in gardening, I have done nothing with either since I moved in 15 years ago!

Both have concrete block edging on the path side and the patio will run up against them. The sections will slope outwards at a 1:60 gradient to the grey lines along each garden wall.

At the top left corner is a small tree of some sort which will stay there and there's a curved section at the bottom left (not visible in the photo) which will probably get a small bush of some sort planted in it.

The house is at the bottom of the diagram and the shed is at the top. The smudge bottom right is where there'll be a table and chairs

From what I can tell, because of the length of the patio sections and them only being 1.3m and 2.3m long, a soakaway wouldn't be necessary.

I believe that underneath the soil is a mixture of sand, gravel and clay.

On the left is the narrow strip 1.3m wide. At the far end of that is a dead tree that's going to be removed. Behind that is a tree that's staying there.

Down the centre is the path leading to the shed at the back and my washing line.

On the right is the 2.3m wide section with another bit of dead tree that has already been cut down!

I hope this clarifies things a bit...

[Grahamm]

I laid my mothers patio, 25yrs ago

Thanks for that.

I think that, given the size, we can get away with using the sand method as described above and save the hassle of having to mix concrete etc.

If it all goes wrong, it shouldn't be too difficult to dig out the sand and concrete it instead.

[Grahamm]

I've been using this for jointing between the slabs.

Hmm, mostly good reviews, but some of the negative ones are a bit off-putting.

As with the sand/ concrete situation, I'll try the fine sand method for jointing, but, if not, I can dig it out and use a compound like that instead.

[fazersharp]

I've been using this for jointing between the slabs.

Hmm, mostly good reviews, but some of the negative ones are a bit off-putting.

As with the sand/ concrete situation, I'll try the fine sand method for jointing, but, if not, I can dig it out and use a compound like that instead.

If you have virtually no gaps between your slabs, a good tight butt join then use kiln dried sand to brush in.
 

[BBROWN1664]

Looking at that photo, I would be wondering why the neighbours patio has subsided so much.

I would still be wary of undermining those walls with water running off the patio too.

[Grahamm]

If you have virtually no gaps between your slabs, a good tight butt join then use kiln dried sand to brush in.

Yes, that's what we're looking at.

[Grahamm]

Looking at that photo, I would be wondering why the neighbours patio has subsided so much.

I'm pretty certain that it's because whoever built that didn't use a proper, compacted hardcore layer.

According to a http://www.landis.org.uk/soilscapes/index.cfm, this part of Portsmouth is on "Freely draining slightly acid loamy soils"

I would still be wary of undermining those walls with water running off the patio too.

The thing is, because the ground is effectively flat (the gardens to the left and right are at the same level and there's no real slope towards or away from the shed) I can't see where any soil could be washed away from/ to.

So the water should just percolate down through the soil on each side, I'm just wondering how quickly it would do this and whether it would end up waterlogging anything that was planted there.

[Grahamm]

By the way, in case anyone is wondering...

Although the area to be paved is more than 5 square metres, provided I allow a method to allow water to drain away ie to a border and not into the sewers, I wouldn't need planning permission:

https://www.planningportal.co.uk/info/200130/common_projects/45/paving_your_front_garden

https://www.paving.org/index.php/planning-permission-for-paving-a-garden/

[agricola]

You have the tallest washing line poles I have ever seen. Are you Twizzle?

[fazersharp]

You have the tallest washing line poles I have ever seen. Are you Twizzle?

I thought that too.
Paint it white and you got a flag pole.

[Grahamm]

You have the tallest washing line poles I have ever seen. Are you Twizzle?

I had no idea what Twizzle was, then I discovered a Gerry Anderson production that I'd never heard of!

However, originally the washing line poles had a pulley wheel at the top such that you could dry two lines of washing as you'd lower the top line down, peg out the washing, then haul it up to dry whilst you put another line of washing on the bottom line

See: https://www.linepost.co.uk/washing-clothesline-product-specifications/