Private drive: what material to choose? - Standard, permeable or grass paving?

[Douglas deL]

I have had quotations for paving my drive with standard blocks. One operator has now suggested Formpave instead: he says it will save digging drains. I'm a bit worried as we are on heavy clay, and the drive slopes (slightly) towards the house. No-one suggested grass paving. What criteria may help me choose the best?

[Ross-Paving]

If you have concerns about the drainage within the drive area, due to the heavy clay, then you should look at the consequences of poor drainage with whichever system you favour.
Personally I always favour incorporating adequate drainage, the belt and braces approach will ensure no regrets when the heavens open.

[Tony McC]

Formpave are a manufacturer, not a type of block. It's akin to saying that if your drive was paved with Marshalls or with Tobermore, you wouldn't need to install drainage.

Formpave manufacture a permeable paving system that, when properly installed, does not need any traditional drainage system, but, if you;re on heavy clay, such a system may not be feasible, and if it was, then the installation cost for a permeable pavement on a small area (say less than 150 square metres) is higher than the cost of installing a 'standard' block pavement, complete with point or linear drainage.

I think you need to go back to the drain-free clown and find out just how the surface water will be disposed.

[Douglas deL]

Thanks, both. The puzzling thing is that this is the contractor who seemed most clued-up about drainage and provided in his first quote the most comprehensive drainage plan. Maybe he's gotten cold feet since then!

What about grassed paving. Does it compete for an application like this?

[Tony McC]

Despite what the manufacturers and suppliers claim, I've never yet seen a grass pavement that has been successfully used as a driveway. I've seen plenty that are bald quagmires, but even when the cells are only partially filled, the grass just can't cope with regular trafficking.

[Douglas deL]

Again, thanks for your comments, Tony. We went for our first option, and were generally pleased with the work which includes a drain to a large soakaway (we are on heavy clay). However, the drain stops at the bay of the house, and therefore is not near an air brick in the bay. The paving butts right up to the air brick, and there is no fall away from it. The builder says it is fine, but am I right to be worried?

I've put a couple of pictures up at <http://www.de-lacey.org/england/del2/airbrick.html>. I'd like reassurance (or the other thig!) before I pay the bill.

Many thanks,
Douglas.

[Tony McC]

I'm confused.

Why was a linear channel drain installed virtually against the house brickwork?

Why wasn't the path laid with crossfall away from the house and towards the garden?

Why was the paving laid so close to the dpc? There is not the requisite 150mm between paving and dpc: more like 75mm

Why has a plain concrete edging kerb been used as an edge restraint? Coloured concrete decorative paving with a plain concrete utilitarian edging kerb? It's like black tights and white high heels!

What's the black thing perpendicular to the air-brick? Looks like an expansion joint cap: is it?

This soakaway cut into the clay - how will that work? What size is it, roughly?

[Douglas deL]

> I'm confused.

> I'm confused.

Yes, I am too, a bit. But I'm sorry, I didn't explain clearly.

> Why was a linear channel drain installed virtually against the house brickwork?

> Why wasn't the path laid with crossfall away from the house and towards the garden?

The garden as a whole has a significant fall towards the house. All the quotes we got suggested some sort of drainage near the house because of this. I'm a novice: why are you suggesting it's bad? I had expected some crossfall, but the path is exactly level.

> Why was the paving laid so close to the dpc? There is not the requisite 150mm between paving and dpc: more like 75mm

Yes, that's worrying. I had just assumed that the builder would work according to regs. He says the concrete was at the same level, and since he's ripped it out I can't contradict -- only point out that 2 wrongs ...

Why has a plain concrete edging kerb been used as an edge restraint? Coloured concrete decorative paving with a plain concrete utilitarian edging kerb? It's like black tights and white high heels!

Yes, I hadn't expected that; his drawing did not specify materials. I can *just* about live with it but I like your simile:-)

> What's the black thing perpendicular to the air-brick? Looks like an expansion joint cap: is it?

Sorry, I should have mentioned: it's a foot rule to give scale.

>This soakaway cut into the clay - how will that work? What size is it, roughly?

It's nearly 1m^3, hollow plastic boxes. We are on a thick seam of heavy clay and in digging the hole for the boxes he certainly didn't penetrate it. Better than the alternative qoutes which were for smaller rubble-filled sumps.

So: what are my options now, d'you think?

[Tony McC]

Douglas said...
I didn't explain clearly

It's not your explanation that has me confused - it's the way the drive has been constructed!

The garden as a whole has a significant fall towards the house

OK - that's not all that unusual, but why wasn't the water intercepted before it runs onto the paving from the garden? In such a scenario, it makes more sense to have the linear channel drain at the outside edge of the paving, so the paving can fall away from the house towards the channel and run-off from the garden doesn't have to swill across the pathway.


...says the concrete was at the same level, and since he's ripped it out I can't contradict...

That's bollocks. You employ a contractor to do the work correctly. If it was wrong before, they should not put in the new paving so that it too is "wrong". Imagine you had a front dor that was loose and draughty: if you asked a builder to replace the door, would you be happy if the replacement door was loose and draughty? Even if the builder told you they could only do the same as what was there previously?

You paid good money for a good job - don't be bullshitted into accepting sub-standard work.



...plain concrete utilitarian edging kerb...

This particular form of construction is usually associated with those who are out of their depth with paving work. In almost 30 years of laying block paving, I've only ever met two genuine contractors that used a pcc edging as a retainer. I've met a few who were obliged to construct the paving that way because some arsehole architect didn't know any better and was too proud to admit their error, but 99.99% of regular paving contractors would not use that construction, and so it is one of those 'indicators' I use when conducting quality assessments for the Trading Standards - it almost always indicates a "builder" that does not understand what it is they are doing.


...it's a foot rule to give scale...

Aaaah! Now I understand. I never though of that, but then we are so familiar with looking at 200x100mm blocks we don't normally need a scale reference.



...It's nearly 1m^3, hollow plastic boxes...

So: it's summat like this? Given the failure to understand restraining edges, I don't hold out much hope for the SUDS storm crates. All you can do is see how it copes with the winter. My concern is that once the crates are filled with water, they will be slow to drain and so provide very little storage for when we get the prolonged downpours.

Did the actual installation of these storm crates bear any resemblance to that show on the page quoted above?

[Douglas deL]

Douglas said...
I didn't explain clearly

It's not your explanation that has me confused - it's the way the drive has been constructed!

The garden as a whole has a significant fall towards the house

OK - that's not all that unusual, but why wasn't the water intercepted before it runs onto the paving from the garden? In such a scenario, it makes more sense to have the linear channel drain at the outside edge of the paving, so the paving can fall away from the house towards the channel and run-off from the garden doesn't have to swill across the pathway.


...says the concrete was at the same level, and since he's ripped it out I can't contradict...

That's bollocks. You employ a contractor to do the work correctly. If it was wrong before, they should not put in the new paving so that it too is "wrong". Imagine you had a front dor that was loose and draughty: if you asked a builder to replace the door, would you be happy if the replacement door was loose and draughty? Even if the builder told you they could only do the same as what was there previously?

You paid good money for a good job - don't be bullshitted into accepting sub-standard work.



...plain concrete utilitarian edging kerb...

This particular form of construction is usually associated with those who are out of their depth with paving work. In almost 30 years of laying block paving, I've only ever met two genuine contractors that used a pcc edging as a retainer. I've met a few who were obliged to construct the paving that way because some arsehole architect didn't know any better and was too proud to admit their error, but 99.99% of regular paving contractors would not use that construction, and so it is one of those 'indicators' I use when conducting quality assessments for the Trading Standards - it almost always indicates a "builder" that does not understand what it is they are doing.


...it's a foot rule to give scale...

Aaaah! Now I understand. I never though of that, but then we are so familiar with looking at 200x100mm blocks we don't normally need a scale reference.



...It's nearly 1m^3, hollow plastic boxes...

So: it's summat like this? Given the failure to understand restraining edges, I don't hold out much hope for the SUDS storm crates. All you can do is see how it copes with the winter. My concern is that once the crates are filled with water, they will be slow to drain and so provide very little storage for when we get the prolonged downpours.

Did the actual installation of these storm crates bear any resemblance to that show on the page quoted above?

Tony said:
OK - that's not all that unusual, but why wasn't the water intercepted before it runs onto the paving from the garden?
Well, we weren't given a choice, but I'd guess because of the difficulty of having adequate fall to the lawn without ending up above the DPC!

So: it's summat like this?
Yes, that'e the baby: two of those. I'm afraid I wasn't around when they put it in, but there was certainly geo-textile around. I didn't notice any delivery of gravel though other than the block substrate. Another thing to ask (he's coming round tomorrow evening for a talk) -- I may well need to come back to you afterwards!

Thanks again,
Douglas.

[Tony McC]

OK - let us know how it goes.

[Douglas deL]

Thanks again for all the help. I got a local builder (who was brought up two doors down the road) and we worked out a compromise solution. Not the best, but the whole of the non-drive area has been dropped (only a few mm admittedly, but to below the airbricks) and given increased drop away from the house. The contractor agreed to do the job (much of a day's work) for free and I think we are all (sort-of) satisfied. And I have gained experience, which they say is cheap at any price...

Douglas.