Patio / driveway drainage

[bhwh]

Hi all

As the pics below show, I am in the process of simplifying and enlarging our driveway, using some of the huge patio the previous owners had installed, to instead use the area as gravelled driveway. This will avoid the current situation of cars being 'queued' up in a line and therefore lots of shuffling of cars to get them in/out in different sequences. A wider driveway will allow side by side parking and a turning area.

I'm currently setting out and planning - the area I'm stuggling with is drainage... how to ensure the best possible drainage away from the house and off the surfaces, making use of existing as far as possible.

The existing patio has adequate fall and crossfall, draining into the linear drain which feeds into the sewer (manhole cover just about visible in final pic where my son is standing!).

As you can see, I would like to construct a sweeping low retaining wall which will retain the new gravelled driveway surface (separate question here of whether I cut the existing slabs to lay this brick wall or just lay on top of the solid bed slabs?)

The question is... do I keep the existing linear drain? Protect it from silting using a textile? Do I try to incorporate some perforated pipe along length of the curved retainer? Link this into the existing linear somehow? Or does this old drain become redundant if sat at the bottom of the compacted subase?

Thanks

Pics....

https://drive.google.com/file....iew

https://drive.google.com/file....iew

https://drive.google.com/file....iew

[vinny40405]

I am just a DIY enthusiast so my thoughts are if it was mine and i would ask for help. I would try to use your linear channel although can you fit the stronger tops on them so that a car can go over? Looking at Tonys drawings of a drive and when I made my patio it was working out the run off areas off water, eg how do you want the water to fall to and drain away? Maybe a rough sketch of above would be better sitting gulleys and the linear channel to help?
I would try and keep the drain if its able to use for drainage, draw a top view and see if it works.
if the stones are large enough they should no go in the drain?
hope fully you can use the drain or raise it if it helps.
Setting out should take some time, easier to plan and get it right on paper first.
Vincenzo

[bhwh]

Thanks Vinny. I am just keen DIY'er too. Happy to admit defeat when needed. If needed, I will hold my hands up and pay for the job to be done by wiser folk!

I'm taking my time over this to get it right and you give a good idea - drawing out a plan, marking on the fall with drainage. The linear drain is very effective in it's current position, so yes I'm looking to make best use of it. It will be hidden well below, underneath the compacted subase though so just trying to get my head around that....

will draw a plan next...

[vinny40405]

have a look on tonys site. there is a part where he explains how to plan or look for the fall of the patio

[bhwh]

Will do. I spend quite a bit of time reading through ... but it’s so extensive, I keep finding more bits that are relevant. I’ll read up on fall / cross fall.. ta

[Tony McC]

Can you provide me with a sketch of what it is you are trying to achieve?

[bhwh]

Thanks for offering to take a look Tony.

I’m better sketching up on paper than software, so will do it this eve when I get in.

[bhwh]

Tony - here's a very quick sketch of what I'm trying to achieve. Vehicles enter the driveway from the bottom left of picture. Currently they stop before the concrete base (see earlier pics on OP). But we would like to swing around and park two cars side by side.

[bhwh]

The sketch shows the proposed plan.

Missing features / labels:

- I have had a quote from local dry stone waller to face the large retaining wall that surrounds the driveway with Cotswold stone. The cost of this is too high at this stage as we cannot be certain that future alterations to the house wouldn’t disrupt this large wall. The proposed solution is to clad the wall with large vertical timbers (gravel board type).

- the existing linear drain will be kept in service; however the section that will become buried under the sub base to be covered with Terram textile to prevent build up of silt

- existing fall away from the house means that rainwater will run off slabs, through copious weep holes left in small curved retainer (mortar joints on bottom course will be left open) and run through free draining material used to fill the void created in this new raised section

- adequate fall/crossfall to be created on new gravelled driveway (centre of diagram) to allow water to run away from large retaining wall towards existing linear drain

- one challenge is dealing with the existing concrete base, leftover from an old ‘marley’ concrete double garage which we removed. In the future we may wish to add an oak framed garage, possibly with room above. So we want to keep the concrete base in case it will be needed again. Knowing that gravel on top of hard surface would create marbles effect, we plan to use a geo-cell gravel stabilising product that is permissible over concrete. The technical team at Core Landscaping Products have confirmed that this type of installation is acceptable. See HERE

- due to the height difference between concrete base/central drive section and the driveway next to house, I may need to extend the gravel stabilising product further than the concrete base in order to stabilise the shallow slope

- natural fall towards bottom left of driveway, I am considering what land drainage might be required? Currently there is none but we are experiencing some puddling in heavy rain plus I know that it is responsibility of homeowner to take care of water runoff and not dispense onto highway

[Tony McC]

I can't see any major issues with what you're proposing. Burying the linear channel is less than ideal, admittedly, but by protecting it with a *construction grade* geo-textil (make sure it is NOT aso-called Landscape Fabric or Weed Membrane) you should be OK. You'd still have maintenance access from the exposed patio end, so I can't see anything to worry about.

[bhwh]

That's reassuring, thanks.

One further niggle in the back of my mind.. should i cut into the existing slabs to lay the small curved retaining wall, or trust that the slabs provide a good enough base? They are stone-look concrete and laid by previous owner on solid bed of mortar, on top of sand. Feels unnecessary to remove but...

[vinny40405]

my view and what i have found in the past that if you try to do it the quick way it might or will bite you. If you do it properly so put a good base down. There should be no problems.
I put a patio following Tonys design and spec. On one part where the motorcycle came in from the alleyway over the slabs it settled slightly when it rained there was a puddle. The reason was that when I was going over the sand with a compactor i thought it was overkill. Just shows if i had persisted it would have been fine i guess.