This permeable paving.....
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wcroz99
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Some great points there Pablo, thats exactly why I try to avoid it as its a bit of a waste of time in my opinion. But, there are people out there that are willing to paying extra if they believe they are saving the environment. Perhaps with all the wet weather we have had this year, we may see customers requesting permeable paving more often.
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Tony McC
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Permeable block paving (CBPP) just hasn't taken off for residential driveways, despite all the bullish predictions from the manufacturers back in 2008 when the comedy legislation was launched' because there are significantly cheaper ways of achiveing the same result.
If you take the average British driveway, which is 48.5m², why would you excavate to, say, 450mm and generate and additional 14m³ of spoil (two good wagon loads) when you could drain the lot to a 2m³ soakaway? It's economic and logistical madness!
Slightly different scenario on commercial schemes, where the case for CBPP is much stronger, and I get angry when I see brand new commercial parking areas, such as the two bloody huge new supermarkets built in nearby Leigh in the last 12 months, being surfaced with blacktop. Firstly, what sort of corrupt planning scheme allows an impermeable surface to be specified on such large and low-lying areas within a known flood plain, and secondly, why are the economics so skewed to favour impermeable paving? There should be financial incentives, whether it's via tax advantages or punitive planning charges, that make permeable paving (and I'm quite happy to see permeable blacktop, if that's what designers prefer) the default surface of choice.
Returning to the residential market, I've been out to assess four so-called CBPP installations this year and in every case, the contractor didn't have a chuffing clue what they were doing, ranging from the pillocks in Warrington who used crudely broken 3x2s as a sub-base to the moron in Chadderton who used at least 20 bags of KDS on a 40m² CBPP driveway. Now, we all know there are contractors out there who *do* know how to do the job, but they are then pricing the work accurately, whereas these eejits have no understanding of the procedure and materials, and are consequently under-pricing the job and winning the work on cost alone.
Finally: rainwater harvesting. It may seem like a crazy idea to us in the north and west of these islands, Pablo, but it's of HUGE interest in the chalk areas of Lower Britain where hosepipe bans and parchged summers are the norm for many and the opportunity to have their own private supply of water for the garden and/or washing the car, is highly attractive.
I designed a RWH scheme in Kent where the property owner had a 1 acre small holding that was slowly dtying due to the hosepipe ban. Installing a harvesting system for the 80m² roof and 140m² driveway now provides just about enough water to get them through a normal summer. It cost roughly 8,000 quid extra for the tank and the pump and the pipework, but the client considers that to be excellent valuie as it means the smallholding and garden thrive, his metered water bills are reduced, and he's looking at a service life of at least 25 years. If growing veg, keeping chickens and ponies, and having a stunning garden were your hobby, would 320 quid/year (8,000 ÷ 25) or less than a pound per day seem like money well spent?
If you take the average British driveway, which is 48.5m², why would you excavate to, say, 450mm and generate and additional 14m³ of spoil (two good wagon loads) when you could drain the lot to a 2m³ soakaway? It's economic and logistical madness!
Slightly different scenario on commercial schemes, where the case for CBPP is much stronger, and I get angry when I see brand new commercial parking areas, such as the two bloody huge new supermarkets built in nearby Leigh in the last 12 months, being surfaced with blacktop. Firstly, what sort of corrupt planning scheme allows an impermeable surface to be specified on such large and low-lying areas within a known flood plain, and secondly, why are the economics so skewed to favour impermeable paving? There should be financial incentives, whether it's via tax advantages or punitive planning charges, that make permeable paving (and I'm quite happy to see permeable blacktop, if that's what designers prefer) the default surface of choice.
Returning to the residential market, I've been out to assess four so-called CBPP installations this year and in every case, the contractor didn't have a chuffing clue what they were doing, ranging from the pillocks in Warrington who used crudely broken 3x2s as a sub-base to the moron in Chadderton who used at least 20 bags of KDS on a 40m² CBPP driveway. Now, we all know there are contractors out there who *do* know how to do the job, but they are then pricing the work accurately, whereas these eejits have no understanding of the procedure and materials, and are consequently under-pricing the job and winning the work on cost alone.
Finally: rainwater harvesting. It may seem like a crazy idea to us in the north and west of these islands, Pablo, but it's of HUGE interest in the chalk areas of Lower Britain where hosepipe bans and parchged summers are the norm for many and the opportunity to have their own private supply of water for the garden and/or washing the car, is highly attractive.
I designed a RWH scheme in Kent where the property owner had a 1 acre small holding that was slowly dtying due to the hosepipe ban. Installing a harvesting system for the 80m² roof and 140m² driveway now provides just about enough water to get them through a normal summer. It cost roughly 8,000 quid extra for the tank and the pump and the pipework, but the client considers that to be excellent valuie as it means the smallholding and garden thrive, his metered water bills are reduced, and he's looking at a service life of at least 25 years. If growing veg, keeping chickens and ponies, and having a stunning garden were your hobby, would 320 quid/year (8,000 ÷ 25) or less than a pound per day seem like money well spent?
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Nigel Walker
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I have installed 3 permeable paving jobs in last 5 years. One was for an Eco Development, the other two were on large flat courtyard / parking areas that had buildings on 3 sides.
On the above projects Permeable block paving was justified and worked great.
However, installing permeable paving on normal domestic drives is total nonsense.
What is the point in spending an extra 25-35% for permeable paving when the water all goes to the same place. Let me explain - Traditional block paving - we install Aco Channels at bottom of driveway or at the lowest point, which are connected into a soakaway, with an overflow into surface water drains if the ground is not ideal for soakaways.. Permeable paving - water drains through the blocks and sub stone, drains to the lowest point and then into a soakaway.
How can anyone justify the extra spend when it does the same thing - if you comply with the regs.
Someone has installed a Permeable drive locally. Its 2.5m wide by 6m long - single car driveway. Drive slopes from garage to the road by about 2m, there are walls on both sides of the driveway. There is no where for a soakaway, unless you are gonna pump water up 2m in height. Where the hell is the water going from the permeable drive ? Its gonna collect under the paving at the lowest point and drain slowly onto the highway. Bloody crazy !
I agree with Tony, that all commercial projects should be Permeable, where possible. How many supermarket car parks have you been in where there are hundreds of puddles - either badly laid tar or drains cant cope.
Agree with Mick regarding worst year for rain that i have known. Kind of getting used to wearing waterproofs on almost daily basis.
On the above projects Permeable block paving was justified and worked great.
However, installing permeable paving on normal domestic drives is total nonsense.
What is the point in spending an extra 25-35% for permeable paving when the water all goes to the same place. Let me explain - Traditional block paving - we install Aco Channels at bottom of driveway or at the lowest point, which are connected into a soakaway, with an overflow into surface water drains if the ground is not ideal for soakaways.. Permeable paving - water drains through the blocks and sub stone, drains to the lowest point and then into a soakaway.
How can anyone justify the extra spend when it does the same thing - if you comply with the regs.
Someone has installed a Permeable drive locally. Its 2.5m wide by 6m long - single car driveway. Drive slopes from garage to the road by about 2m, there are walls on both sides of the driveway. There is no where for a soakaway, unless you are gonna pump water up 2m in height. Where the hell is the water going from the permeable drive ? Its gonna collect under the paving at the lowest point and drain slowly onto the highway. Bloody crazy !
I agree with Tony, that all commercial projects should be Permeable, where possible. How many supermarket car parks have you been in where there are hundreds of puddles - either badly laid tar or drains cant cope.
Agree with Mick regarding worst year for rain that i have known. Kind of getting used to wearing waterproofs on almost daily basis.
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Tony McC
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rab1
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sy76uk
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Tony McC
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There's summat wrong if the joints are silting-up to the point of losing permeability after just a couple of years. I've seen research where 8-10 year old pavements in commercial areas are functioning perfectly well even with 60-70% silting. Is the site haveliy silted? Is there a lot of detritus washed across the surface?
One thing that rarely gets mentioned with permeable block paving CBPP is that it needs annual maintenance in the form of thorough sweeping to remove any surface vegetation from the joints and possibly a blast with a jet washer to loosen the grit in the joints, which may also then need topping-up.
Properly maintained, you should be looking at a minimum 20 year service life.
One thing that rarely gets mentioned with permeable block paving CBPP is that it needs annual maintenance in the form of thorough sweeping to remove any surface vegetation from the joints and possibly a blast with a jet washer to loosen the grit in the joints, which may also then need topping-up.
Properly maintained, you should be looking at a minimum 20 year service life.
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sy76uk
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I couldn't tell you about every job I've done in permiable because I've done more than I can remember over the years and it has all been for a big paving firm so it wouldn't have been me that got the phone call a few years down the line to say that the paving is holding water but I've been sent to plenty of jobs that have needed lifting and re laying due to the problems I mentioned above and a fair few have been on sites that are only a couple of years old. All of them have been big commercial jobs too by the way so they have all had the proper sub-base installed.
I think some of the problems are,
1, If the grit used for jointing is too fine it's too hard for the water to find it's way through even when it's brand new so after a few years of dirt in the joint's it doesn't stand a chance.
2, If the area is cleaned often by a road sweeper all the jointing grit is sucked out and the joints just get filled up with dirt and sealed.
3, If the site is half permiable, half tarmac and the permiable area is used as a drainage area then all the muck gathers over the block paved area and seals it all.
Just my point of view from my own experience.
I have done some really nice area's in permiable though, I'm not against it. I just don't think it does what it says on the tin as well as it should.
I think some of the problems are,
1, If the grit used for jointing is too fine it's too hard for the water to find it's way through even when it's brand new so after a few years of dirt in the joint's it doesn't stand a chance.
2, If the area is cleaned often by a road sweeper all the jointing grit is sucked out and the joints just get filled up with dirt and sealed.
3, If the site is half permiable, half tarmac and the permiable area is used as a drainage area then all the muck gathers over the block paved area and seals it all.
Just my point of view from my own experience.
I have done some really nice area's in permiable though, I'm not against it. I just don't think it does what it says on the tin as well as it should.
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lutonlagerlout
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lemoncurd1702
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I've mentioned this on another thread.
I have received specs for commercial works where the specified base is type 1 with coarse sand and permeable paving jointed with kiln dried.
It's doomed to failure until some body or other polices this. If needs be this body should insist on a relay, that should make the rest comply.
Personally I hate the stuff, the finish looks shite.
Besides the extra cost of excavation the producers of permeable blocks somehow believe the paving should also be more expensive even though most of it is based on run of the mill existing products.
Do they really believe that the average consumer gives enough of a f**k to pay extra for an inferior finish.
Especially if they live on a hill
I have received specs for commercial works where the specified base is type 1 with coarse sand and permeable paving jointed with kiln dried.
It's doomed to failure until some body or other polices this. If needs be this body should insist on a relay, that should make the rest comply.
Personally I hate the stuff, the finish looks shite.
Besides the extra cost of excavation the producers of permeable blocks somehow believe the paving should also be more expensive even though most of it is based on run of the mill existing products.
Do they really believe that the average consumer gives enough of a f**k to pay extra for an inferior finish.
Especially if they live on a hill
Cheers
Lemoncurd
Lemoncurd
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Tony McC
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If the CBPPs are jointed with sand or the wrong type of grit, then it is bound to fail. This is largely down to poor training.
In cahoots with Interpave, I helped create a 1-day training course for CBPP, half theory, half practical, but the useless gits responsible for delivering the training never actually bothered. At one point, in a move designed purely to annoy me by refusing to let me lead the first few courses, train the trainers as it were, they had a retuired overweight, unfit bricklayer leading the course and he had to ask the lads how to set out a 90° herringbone, which then destroyed what little credibility he had with his trainees.
So, while some of the manufacturers have cannibalised the Interpave/pavingexpert CBPP course to present their own simpler, half-day courses for residential projects, there is no effective training for commercial projects, which is why we see so many problems. I've shouted as loudly as I can. It's down to Interpave to ensure the training is both available and actually delivered (by competent person rather than feckwitts or salesbods!)
When cleaning is undertaken, it *must* be done with the right sort of kit. A standard road sweeper is NOT the right sort of kit. And when cleaning is complete, the jointing must be topped-up using the right sort of grit. Again, this comes down to training.
As I've already said, I know of CBPP surfaces approaching a decade of trouble-free service because they were properly installed and then properly maintained.
As for the cost, I've been saying for 10 years that it is WRONG of the manufacturers to charge more per m² for CBPP than for conventional CBPs. Think about it: with that 6mm or so joint, there is actually *less* concrete per m² with CBPPs, so how can it be right to charge more? I've heard all the arguments about recovering R&D costs, smaller sales volumes, and so on, but it's not acceptable to whinge about poor sales voulmes whilst not actively doing very much to promote the products via sensible pricing!
And again: if I can get a grant to stuff my loft and walls with insulation, and to hang a new boiler in the kitchen, why can't I get a grant to make my new driveway permeable? Flooding and the way we handle surface water is just as important as carbon emissions and energy usage....as many have seen to their cost over the winter!
Now that I've finally got the machine-lay page finished and published, my next big project will probably be CBPPs. Like it or lump it, this is a technology that we as a society will have to adopt because dumping surface water into the sewer systems is becoming increasingly unacceptable.
In cahoots with Interpave, I helped create a 1-day training course for CBPP, half theory, half practical, but the useless gits responsible for delivering the training never actually bothered. At one point, in a move designed purely to annoy me by refusing to let me lead the first few courses, train the trainers as it were, they had a retuired overweight, unfit bricklayer leading the course and he had to ask the lads how to set out a 90° herringbone, which then destroyed what little credibility he had with his trainees.
So, while some of the manufacturers have cannibalised the Interpave/pavingexpert CBPP course to present their own simpler, half-day courses for residential projects, there is no effective training for commercial projects, which is why we see so many problems. I've shouted as loudly as I can. It's down to Interpave to ensure the training is both available and actually delivered (by competent person rather than feckwitts or salesbods!)
When cleaning is undertaken, it *must* be done with the right sort of kit. A standard road sweeper is NOT the right sort of kit. And when cleaning is complete, the jointing must be topped-up using the right sort of grit. Again, this comes down to training.
As I've already said, I know of CBPP surfaces approaching a decade of trouble-free service because they were properly installed and then properly maintained.
As for the cost, I've been saying for 10 years that it is WRONG of the manufacturers to charge more per m² for CBPP than for conventional CBPs. Think about it: with that 6mm or so joint, there is actually *less* concrete per m² with CBPPs, so how can it be right to charge more? I've heard all the arguments about recovering R&D costs, smaller sales volumes, and so on, but it's not acceptable to whinge about poor sales voulmes whilst not actively doing very much to promote the products via sensible pricing!
And again: if I can get a grant to stuff my loft and walls with insulation, and to hang a new boiler in the kitchen, why can't I get a grant to make my new driveway permeable? Flooding and the way we handle surface water is just as important as carbon emissions and energy usage....as many have seen to their cost over the winter!
Now that I've finally got the machine-lay page finished and published, my next big project will probably be CBPPs. Like it or lump it, this is a technology that we as a society will have to adopt because dumping surface water into the sewer systems is becoming increasingly unacceptable.
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sy76uk
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I agree with your point about poor training being responsible for failure as far as domestic work is concerned but not on commercial projects. On all of the commercial installations I've been involved with we have to work to the specifications we are given regardless of my experience or opinion.
One real plus point for permiable paving for me is that you can lay it in all weathers
[IMG]http://i952.photobucket.com/albums....MG]
[IMG]http://i952.photobucket.com/albums....MG]
One real plus point for permiable paving for me is that you can lay it in all weathers
[IMG]http://i952.photobucket.com/albums....MG]
![[IMG]http://i952.photobucket.com/albums....MG]](http://s952.photobucket.com/user/sy76uk/media/16122010013.jpg.html){kind=link}
[IMG]http://i952.photobucket.com/albums....MG]
![[IMG]http://i952.photobucket.com/albums....MG]](http://s952.photobucket.com/user/sy76uk/media/16122010011.jpg.html){kind=link}
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lutonlagerlout
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Tony McC
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Oh, the spec is often right, but the implementation and, critically, the supervision is often wanting,sy76uk wrote:On all of the commercial installations I've been involved with we have to work to the specifications we are given regardless of my experience or opinion.
I've yet to meet a contractor working on a commercial project who was asked to provide evidence of relevant training before undertaking CBPP. The usual 'vetting' runs summat like....
"Can you lay this permeable block stuff?"
"Yeah, not a bother!"
"Get on with it, then"
This is how we end up with jobs laid on Type 1, jobs laid on sand, jobs jointed with KDS, jobs with all cuts omitted and filled with grit instead, and jobs with ineffective or non-existent edge restraint.
On one high-profile job here in Warrington, the eejit contractor convinced the site manager that the spec was wrong because there was not enough fines in the "hardcore", which led to the 20-5 being sent back and replaced with DTp1, with predictable results 3 months later.
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sy76uk
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I've never come across any of the problems you've mentioned above Tony. The first job I did in CBPP was back in 2003. It was a hospital car park in Birmingham city centre. There were a lot of protected tree's in the area and the only way the could do the car park was if they did it in permiable.
On that job we had 2 types of grit to use. 2-5mm for the bedding layer and 0-2mm for the jointing. We ended up running out of 25kg bags of grit for jointing and used the bedding grit for the last 100 or so m2 for brushing in and guess what, that was the only area that didn't hold water. Lesson learned.
The job I posted photo's of above is of a big tesco's car park. All of the parking bay's are CBPP and the roads are tarmac. The tarmac roads are cambered in the centre and the parking bays have a 100mm valley in the centre so that the they act as a soak away for the whole job and the rain water is stored for re-cycling. Nice idea but it get's cleaned by a road sweeper constantly and they just suck all the grit out. We were called back out to the job about a year later re-joint the whole job which was 2400m2. We had to lift and re lay alot of the edges too. Nothing to do with the way we laid it, purely down to poor maintanence.
I've been there once since too. I Did a patio for someone that lives near there and mentioned to them that I did the paving at there local tesco. After nipping there at lunch time I'd wished I hadn't because it looked a right flipping mess.
IMPO the best way to acheive a good finish with the stuff is if it's laid with 100mm of 2-5mm pea gravel screed on a peckered tarmac sub-base with 2-5mm pea gravel brushed into the joints.
I agree with your point's that it need's to be installed and maintained correctly for it to stand a chance but even when it is once the bedding layer get's full of silt it becomes non permiable anyway.
When I say I've done loads of it I'd like to explain that up util early 2012 I worked as a ganger for a big paving firm doing big commercial projects. We would get down at least 500m2 a week on big area's and it was 50/50 permiable-non permiable.
CBPP is a good idea and it keeps the lad's working in the winter but I think the system need's improving.
On that job we had 2 types of grit to use. 2-5mm for the bedding layer and 0-2mm for the jointing. We ended up running out of 25kg bags of grit for jointing and used the bedding grit for the last 100 or so m2 for brushing in and guess what, that was the only area that didn't hold water. Lesson learned.
The job I posted photo's of above is of a big tesco's car park. All of the parking bay's are CBPP and the roads are tarmac. The tarmac roads are cambered in the centre and the parking bays have a 100mm valley in the centre so that the they act as a soak away for the whole job and the rain water is stored for re-cycling. Nice idea but it get's cleaned by a road sweeper constantly and they just suck all the grit out. We were called back out to the job about a year later re-joint the whole job which was 2400m2. We had to lift and re lay alot of the edges too. Nothing to do with the way we laid it, purely down to poor maintanence.
I've been there once since too. I Did a patio for someone that lives near there and mentioned to them that I did the paving at there local tesco. After nipping there at lunch time I'd wished I hadn't because it looked a right flipping mess.
IMPO the best way to acheive a good finish with the stuff is if it's laid with 100mm of 2-5mm pea gravel screed on a peckered tarmac sub-base with 2-5mm pea gravel brushed into the joints.
I agree with your point's that it need's to be installed and maintained correctly for it to stand a chance but even when it is once the bedding layer get's full of silt it becomes non permiable anyway.
When I say I've done loads of it I'd like to explain that up util early 2012 I worked as a ganger for a big paving firm doing big commercial projects. We would get down at least 500m2 a week on big area's and it was 50/50 permiable-non permiable.
CBPP is a good idea and it keeps the lad's working in the winter but I think the system need's improving.