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Posted: Fri May 06, 2016 12:15 pm
by nature500
Hi All,
I recently used cement-based polymeric sand to fill the joints in garden block paving (approx 40 sq m). I used only a brush to remove the sand from the paver surface (not a leaf blower unfortunately) and now I'm left with a white haze.
What is the best way to remove this white haze from the surface, without damaging the filling in the joints? Would a chemical-based solution render the joint filling useless? Some of the paver also meets lawn so would be good to know if the lawn would be damaged by the chemicals.
Thanks,
Ollie.
Posted: Sat May 07, 2016 6:29 pm
by Tony McC
There's no such thing as a "cement-based polymeric sand". It's either cementitious or it's poymeric; it can't be both. It's like saying you have a petrol-engined diesel car.
If it genuinely is "cement-based", the staining will be....err.....cement, so it needs to be cleaned accordingly.
PS - I'm not so sure about "garden block paving" either. It's just "block paving".
Posted: Sun May 08, 2016 8:01 am
by lutonlagerlout
sounds like it might be the old "KDS and cement " routine
not a good idea
what exactly did you use nature500?
LLL 
Posted: Sun May 08, 2016 8:49 am
by nature500
Hi,
I used Dansand no weed flexible paving joint filler. Just checked and definitely contains cement.
Thanks
Posted: Mon May 09, 2016 2:01 am
by lutonlagerlout
I just read the data sheet,there is zero cement in it
which means you just have a haze of the binders which will be some kind of plant oils
I would leave it alone and let the weather get at it
these kind of sheens are quite common with polymeric materials
cheers LLL
Posted: Mon May 09, 2016 9:55 am
by Brucieboy
Sorry LLL, I disagree. The data sheet for Dansand's polymeric flexible paving joint filler states "Selected kiln dried sand, cement, various binders and a weed-inhibiting mineral. The main binder consists of a polymer with low environmental impact". Refer to Contents in Technical Specification.
Posted: Mon May 09, 2016 11:19 am
by nature500
This is the product I've used:
http://www.wickes.co.uk/Dansand....0
I wanted to attach a photo but doesn't look like I can - there is a warning message on the back which says "IMPORTANT! Contains cement"
Posted: Mon May 09, 2016 11:33 am
by Brucieboy
Yes, it's the product I referred to. Can you upload a photo of your block paving showing the extent of the white haze problem.
Posted: Mon May 09, 2016 4:50 pm
by lutonlagerlout
my bad guys,I didnt read that far down Doh
sounds an unusual product,claims to be flexible but contains cement??
LLL
Posted: Mon May 09, 2016 9:55 pm
by RAPressureWashing
I've heard of this product, some good things and some not so good, it's supposed to be the answer to stopping weeds in Block Paving? jury's out on that one IMO, I've tried these "polymeric" sands before and all have been crap they don't last, anyway to answer the OP, all you should need is phosphoric acid to remove the hazing, you shouldn't need to use hydrochloric acid AKA brick acid. The phosphoric is a gentler acid and should not change the face of the paver.
Posted: Wed May 11, 2016 12:49 pm
by PavingSuperstore
Dansand was the next big thing a few years back - I remember seeing it at Glee and it was being promoted by Tommy Walsh. I think there were initial difficulties in it being launched in the UK, but then I seem to recall that Bradstone took over the UK rights for a while. Looks like Wickes might be doing it now then. Never used it, but it seemed good in theory with weed inhibitors etc, but think there are probably better alternatives now.
Posted: Wed May 11, 2016 1:04 pm
by nature500
Thanks guys.
So the phosphoric acid should get rid of the haze but leave the binding in tact in the joints?
Jury is also out for me on this product - there are some weeds growing back through, although these could be legacy seeds/roots from before I put the product in - I am going to remove the current crop of weeds and see what happens from here.
Posted: Wed May 11, 2016 3:04 pm
by RAPressureWashing
nature500 wrote:Thanks guys.
So the phosphoric acid should get rid of the haze but leave the binding in tact in the joints?
Jury is also out for me on this product - there are some weeds growing back through, although these could be legacy seeds/roots from before I put the product in - I am going to remove the current crop of weeds and see what happens from here.
Yes the phosphoric should remove the hazing and leave the pointing in tact, BUT make sure you read the instructions fully and use the dilution rates they suggest. Wear the proper PPE as this stuff will burn your skin, and don't get it near your eyes.
For weed killing, Just use something like Round-up it works well on block paving, you just need to keep on top of them.
Posted: Wed May 11, 2016 3:18 pm
by nature500
Perfect - thanks, will do