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Compacted dust and stains on block paving
I have just had a new driveway laid using brindle blocks supplied by Jewson, these were 3 different lengths, 4",6" and 8" laid in lines.
The contractor did a magnificent job but I have an issue with the blocks themselves.
Many of the blocks (approx 20%) have islands of heavily compacted dust on their surfaces which can be partially removed by chiselling with a scraper and scrubbing with a wire brush, about 70% also have white staining which I am told is efflorescence and will probably disappear eventually.
The drive looks magnificent when it's wet, but as soon as it's dry it looks very patchy and pink when it should be a nice uniform dark red buff colour.
Other new drives nearby don't seem to suffer these problems, am I just unlucky or should I do something about it, e.g. demand some new paving blocks?
3 Answers from MyBuilder Driveway Pavers
use a powerful commercial jet wash an some acid based cleaner
and that should remove the stains
Answered 30th Dec 2017
A powerful pressure washer should help get the worst of the muck off the blocks and will help remove the white stains too.
The stains are just from the salts that the blocks have in them. Once this is out you will be fine, but it can take a long time for that to happen. The only thing you can do to remove it is to keep flushing the salts away, so rather than let the stains sit on the blocks after it has rained brush or pressure wash the blocks long before they dry.
Otherwise the salt will rise with the rain water and then just sit there as it dries out. If it rises and you wash the salt away they will become cleaner much sooner.
You are not particularly unlucky with the situation, it simply happens every now and then. You probably have very new blocks that have not sat in the weather long enough on a builder's merchants yard for the rain to rinse the salt out.
If the dust is actually cement then you can use a cement/concrete cleaner which is an acid that dissolves it and then pressure wash that away.
Answered 28th Dec 2017
This sounds like a problem with the blocks. In the first instance you should get the installer back to sort it out. If they need to contact the supplier then they should do this.
Blocks can occasionally have efflorescence which will disappear over time but you have said this is in lumps big enough to chisel off which definitely should not be happening. Get your install back and tell him to sort it. If he is on the Marshall's or other trade register then get on to them.
Answered 1st Jan 2018
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