Bad batch or just damp - Drive dries out unevenly

[john@yahoo]

Hi PavingExperts!
2 years ago I had the front of my house block paved to get the car off the corner of the road. After it rains, the drive does not dry out evenly. There appers to be a batch of blocks that remain wet for ages. Here is a link to a picture.
https://www.box.com/s/zvzrjlwnw01gth0u6ysf
As you can see, most of the blocks dry out quite nicely as does the road and neighbours drives, but this "bad" batch stays damp for a couple of days. They eventually dry out of course.

Apart from it looking unsightly when drying out, I am more bothered about longivity. I think that these blocks will be prone to moss and require more cleaning than the good blocks and probably need replacing when they are really mismatching the good ones.

In case you are wondering whether the car is helping to keep some of the rain away. There has been too many occasions when the whole drive took a drenching, yet the uneven drying was still present.

Here is a picture of an alomst dry drive.
https://www.box.com/s/gng95y859blxokinsmyv
I am sure you must agree that there is a batch of blocks that just look different and behave differently when wet.

I have called the builder back, but at the moment he is not too interested. He is obviously trying to do nothing and blaming burst pipes, me putting stuff on it, the ground is more damp on that section, etc.

Come on PavingExperts, what would you do if your drive was behaving and looking like mine?

[lutonlagerlout]

looks like a dodgy pack of blocks to me
thats why you should always mix packs
in fairness its not the builder's fault ==> he didnt make the blocks
it could be a spillage but without a close look hard to tell
cheers LLL

[Dave_L]

I've had one like this. Best way to deal with it is wait until it is FULLY dry and seal it.

Did that and my customer was over the moon. Cost me 1/2 a day and £40 versus ripping 80m2 up.

[lutonlagerlout]

TBH it looks older than 2 years when i downloaded the file it looks older to me ???
it almost looks to me like something has happened to that section either before or after installation
was the whole area grass or was there an original driveway/?
have you tried any kind of sealants?
LLL

[john@yahoo]

TBH it looks older than 2 years when i downloaded the file it looks older to me ???
it almost looks to me like something has happened to that section either before or after installation
was the whole area grass or was there an original driveway/?
have you tried any kind of sealants?
LLL

Not exactly 2 years old, it was done Nov 2010. The original area was mostly just grass, there was a path to the front door paved with 2 slabs wide is on the right of the drain covers. The affected area and the area just to its left was plain grass.

I have photographs of the progress of the build, I could not see any unusual things the builders did when they laid the base. They seemed to follow the recomendations that I have read on this website.

I darent do anything to the drive myself just yet, I should give the builder a chance to come up with a solution. So am just asking on this forum to compare notes with what he may come up with.

[john@yahoo]

I've had one like this. Best way to deal with it is wait until it is FULLY dry and seal it.

Did that and my customer was over the moon. Cost me 1/2 a day and £40 versus ripping 80m2 up.

I yield to your expertise, but is not the damp coming from underneath? The good blocks dont let through the damp but the dud ones are porous and let the damp rise. So it is difficult to imagine how a sealant fixes this. I know you said it works, do you know how?

[lutonlagerlout]

the area affect looks like they used from 1pack of blocks
to me it looks like that pack was older/different supplier or defective
LLL

[local patios and driveway]

There is a defined difference between what i would call the pourous blocks, i think a sealer would be the next step for certain. I think you'll get great results.

[gonchy]

im no expert here but the edging bricks are damp too at the bottom of that area in both photos so that must rule out bad blocks and point to some issue under drive but like i said not my field

[seanandruby]

im no expert here but the edging bricks are damp too at the bottom of that area in both photos so that must rule out bad blocks and point to some issue under drive but like i said not my field

The clue is that it happens after rain. the guy states that he watched every stage of the procedure so i think we can rule out dodgy ground, leaking pipes etc:

[john@yahoo]

Just to keep you guys interested...

I took out a couple of "wet" blocks and put good ones in their place today. The theory being is that after the next rain, these "dry" blocks wont be "wet" any more.

I know you are dying to know which ones I've changed. Well lets wait for some rain and I'll do another picture and play spot the difference.

To attack this with another prong, these two "wet" blocks, I stood them on end in a tray of water along with a good dry one. I am expecting the two "wet" ones to remain wet from top to bottom and the "dry" one to only be wet only where it is immersed in the water. My theory is that the blocks are porous and water/damp from the base soaks upward making them look wet. Whereas the dry ones are dry because they dont soak up water from the base, they dry quicker because they are just drying surface water.

I only have a handful of spare blocks the builders left behind. I'm assuming they are good ones. They look more like the good ones than the bad ones close up.

[john@yahoo]

There is a defined difference between what i would call the pourous blocks, i think a sealer would be the next step for certain. I think you'll get great results.

Agreed, sealant may be the easiest answer as many of you have already said.

At the moment I'm just trying to identify the root cause and see if there is any compensation from the builder or supplier of blocks.

I guess if that fails sealant is the next step.

[Dave_L]

From experience, you won't get anywhere complaining to the supplier/manufacturer.

[robert jones]

When the bricks are dry use an impregnating sealer ,
This will stop the brick being porous .Unlike topical sealers it wont affect the colour of your brick or fade with sunlight .
Some of your bricks are more porous than others due to manafacturing process ,they will still have same strenght .

[john@yahoo]

The builder did come and take a look, after a bit of convincing that the blocks were faulty (or at least different), he agreed to test my theory. He moved 5 blocks from the wet patch to the middle of the dry patch. We both agreed that if the wet ones stayed wet amongst the dry ones, then the issue would be with the blocks.

We didn't have to wait too long for some rain, here is a picture of the result : https://www.box.com/s/6im98bgwsh103pa305ov
A patch of wet blocks amongst dry ones.

The builder wrote to the supplier and sent me their response. Basically they call it differential drying. They said it was nothing to worry about and the blocks will last as long as any other blocks. The effect is "aesthetic". The blocks are made to BS standards bla, bla bla...

Yes, BS standards, an acronym to something else I have in mind.