Slippy york stone flags - advice needed please

[Racer]

Thanks for allowing me to join. Can I ask for some advice please. We have a large circular pond surrounded by what I think are York stone flags. The paving extends around the house, the driveway and patio areas. As might be expected when the weather is damp the flags become extremely slippy (particularly around the pond area which is also surrounded by trees). I regularly jet wash the whole area and remove the moss deposits thoroughly (a big job) but I'm now fighting a losing battle. The paths are getting more and more dangerous each year (so much so that earlier this year I slipped and fell into the pond - hilarious now but could have had more serious consequences had I whacked my head before ending up in the water). Is there anything I can treat the stone with that will make the surface less prone to moss/algae growth or I am destined to replace the stone with something safer (a huge job). I would really appreciate any thoughts/advice. One major problem we have is that the pond is full of fish so have to be particularly careful with any chemicals. Thanks in advance!

[higgness]

Can you put up some pictures?

[Racer]

Can you put up some pictures?

Many thanks. Have posted some pics below :

Slippy flags pics ...

[RAPressureWashing]

You have 2 choices really, have the pond emptied & cleaned at the same time as getting the paving cleaned to allow chemical use at least around the pool area or you can have it steam cleaned which could be done pretty much without chemicals.
The paving is also covered in Lichen as well as very heavy algae. Pointing in the top photo looks shot in a couple of places as well. Where about's in Cheshire are you, as I might know a company up your way that could clean the paving.

[Racer]

You have 2 choices really, have the pond emptied & cleaned at the same time as getting the paving cleaned to allow chemical use at least around the pool area or you can have it steam cleaned which could be done pretty much without chemicals.
The paving is also covered in Lichen as well as very heavy algae. Pointing in the top photo looks shot in a couple of places as well. Where about's in Cheshire are you, as I might know a company up your way that could clean the paving.

Cheers for the reply. Emptying is not an option unfortunately as it's a natural spring pond (and a lot of fish). Does need some pointing re-doing as you say which I will tackle over Winter and might help a little. Jet washing works well but doesn't take long before it's slippy again unfortunately. Was wondering if there was any sort of chemical/surface treatment I could try to kill off the Lichen/Algae but obviously fish are a problem! - I have access to a steam cleaner if needed but wonder if this would be much more effective than cold water high pressure jetting?

Again - many thanks for your reply - much appreciated.

[Racer]

You have 2 choices really, have the pond emptied & cleaned at the same time as getting the paving cleaned to allow chemical use at least around the pool area or you can have it steam cleaned which could be done pretty much without chemicals.
The paving is also covered in Lichen as well as very heavy algae. Pointing in the top photo looks shot in a couple of places as well. Where about's in Cheshire are you, as I might know a company up your way that could clean the paving.

Cheers for the reply. Emptying is not an option unfortunately as it's a natural spring pond (and a lot of fish). Does need some pointing re-doing as you say which I will tackle over Winter and might help a little. Jet washing works well but doesn't take long before it's slippy again unfortunately. Was wondering if there was any sort of chemical/surface treatment I could try to kill off the Lichen/Algae but obviously fish are a problem! - I have access to a steam cleaner if needed but wonder if this would be much more effective than cold water high pressure jetting?

Again - many thanks for your reply - much appreciated.

[RAPressureWashing]

You have 2 choices really, have the pond emptied & cleaned at the same time as getting the paving cleaned to allow chemical use at least around the pool area or you can have it steam cleaned which could be done pretty much without chemicals.
The paving is also covered in Lichen as well as very heavy algae. Pointing in the top photo looks shot in a couple of places as well. Where about's in Cheshire are you, as I might know a company up your way that could clean the paving.

Cheers for the reply. Emptying is not an option unfortunately as it's a natural spring pond (and a lot of fish). Does need some pointing re-doing as you say which I will tackle over Winter and might help a little. Jet washing works well but doesn't take long before it's slippy again unfortunately. Was wondering if there was any sort of chemical/surface treatment I could try to kill off the Lichen/Algae but obviously fish are a problem! - I have access to a steam cleaner if needed but wonder if this would be much more effective than cold water high pressure jetting?

Again - many thanks for your reply - much appreciated.

For the steam cleaner I'm talking about a clean either a pressure water or a Doff machine that can reach 150-180 degrees for the water turning to steam, so if you have access to this sort of thing then this will remove and kill off the algae and should remove most if not all the Lichen, the flow rate is a lot slower for these type of machines at these temperatures so you should be able to control water that goes into the pond, as at a guess the fall of the paving takes water into it? As for a chemical, get's difficult to recommend one when there is aquatic life involved as even the ECO one's can be harmful to fish etc if care is not used.

[Racer]

You have 2 choices really, have the pond emptied & cleaned at the same time as getting the paving cleaned to allow chemical use at least around the pool area or you can have it steam cleaned which could be done pretty much without chemicals.
The paving is also covered in Lichen as well as very heavy algae. Pointing in the top photo looks shot in a couple of places as well. Where about's in Cheshire are you, as I might know a company up your way that could clean the paving.

Cheers for the reply. Emptying is not an option unfortunately as it's a natural spring pond (and a lot of fish). Does need some pointing re-doing as you say which I will tackle over Winter and might help a little. Jet washing works well but doesn't take long before it's slippy again unfortunately. Was wondering if there was any sort of chemical/surface treatment I could try to kill off the Lichen/Algae but obviously fish are a problem! - I have access to a steam cleaner if needed but wonder if this would be much more effective than cold water high pressure jetting?

Again - many thanks for your reply - much appreciated.

For the steam cleaner I'm talking about a clean either a pressure water or a Doff machine that can reach 150-180 degrees for the water turning to steam, so if you have access to this sort of thing then this will remove and kill off the algae and should remove most if not all the Lichen, the flow rate is a lot slower for these type of machines at these temperatures so you should be able to control water that goes into the pond, as at a guess the fall of the paving takes water into it? As for a chemical, get's difficult to recommend one when there is aquatic life involved as even the ECO one's can be harmful to fish etc if care is not used.

Thanks Roger - that is really useful info. I've just been doing a bit of research on DOFF cleaning and it sounds like it might be the way to go. The machine I have access to is just a 'normal' industrial steam cleaner so nothing like that. I'll read up some more. Again, many thanks for the information. - much appreciated.

[ResiblockBoss]

Hi Racer. Aggregate and sealer is the answer.
Firstly you would need to clean your paving precisely as suggested by Roger and when dry, seal the surface (it must be a ‘sealer’ rather than a ‘coating’ or ‘impregnator’) with a suitable solvent free product (our Resiecco for instance) initially applying with a brush but keeping around 1� from the edge of the pond; and whilst still wet broadcast an appropriate aggregate onto the surface (e.g. aluminium oxide or simply kiln dried sand) and running a wet roller back and forth over the surface to ensure even particle distribution.

A number of our customers have informed us that they have used this method to improve the SRV where typically an inappropriate paving material was used around a swimming pool.

I would suggest you initially carry out a trial in area that will not be seen (under broadleaf planting, flowerpots etc) and that way you can confirm that you are a) happy with the finished aesthetic and b) degree of grip. In the industry the way we would carry out the second is by using Munro Stanley Portable Skid Resistance Tester, but you can carry out an adequate comparison merely by pouring water on the sealed surface and rubbing your boot back and forth and comparing the 'feel' with the untreated area.
Should you wish to do this please PM me with your address and I will send you a sample of Resiecco with my compliments.
Craig

[cookiewales]

would not be a big fan of destroying that york stone with resin

[ResiblockBoss]

Interestingly, I agree with you Cookie.

However it would of course entirely depend on which one is chosen – because to categorise all ‘resins’ as being the same would be to categorise all ‘paving’ as being the same. Rigid, flexible, reinforced concrete, PIC, RBA, tarmacadam, block pavers, flags, setts – are all just ‘paving’, to the uninitiated.

So yes I would concur that if ones knowledge is limited to believing that all ‘resins’ are the same, then one could indeed procure the wrong product, which would of course could ‘destroy’ the aesthetic.
Craig

[higgness]

You seem to have done it before, put up some before and after pictures.
PS, that last posting, one feels it was a bit rude.

[ResiblockBoss]

I sincerely apologise to Cookie if my comments appeared rude, that was certainly never my intention.
We have never done this within the company (we are polymer engineers rather than contractors) however a number of our customers have suggested and used this method to increase the grip around swimming pool areas. I will ask if any have images and if so will certainly post them
Craig

[RAPressureWashing]

In my opinion, all this paving needs is a deep clean with a Doff or similar then every year a maintenance clean, might have to be done twice a year seeing as chemical usage is an issue to keep the algae at bay.With respect Craig for sealing natural stone externally then an impregnating sealer is far better then a topical or coating sealer as no foot traffic wear or peeling.
The idea of "mixing" KDS with a sealer is a bit hit and miss again IMO yes you most probably get grip but unless done properly it's going to look crap.