Sandblast or pressure washer or both?

[pls1]

Would like some advice on cleaning both the coping stones and patio stones around a swimming pool as shown:

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• pls1
• 28 May 2012
• 1

A few things have been tried in the past including cleaning with thin bleach and a scrubbing brush and also using a pressure washer (only 70bar though!)
Results have been poor to satisfactory and usually it needs doing again the following year.
I have read that using a pressure washer on patio stones opens up small pores and makes the problem worse in that they need cleaning more regularly.
I'm wondering if hiring a kit to sandblast them might be a better option and then sealing them? I have also seen sandblasting kits for pressure washers and would be interesting in any feedback from anyone who has used these?

 

[r896neo]

sand blasting and pressure washing are last resort methods and will if done repeatedly damage and remove colour from paving and as you say simply make the surface rougher and even more likely to green up in future.

You need to be more proactive in general cleaning throughout the year. Sealing will help because it will make it easier to keep clean and stop dirt/algae penetrating so deep.

Spraying 2 or 3 times a year with a good hard surface cleaner like MMC Pro or Qualgex should act as a preventative measure too keeping it tip top.

 

[pls1]

What would you recommend to seal the stones once they are cleaned up?

 

[r896neo]

Its not my area of expertise really, but for around a swimming pool with all the associated chemicals you may need a specialist type.

Resiblock and lithofin make good quality sealers so email them to see what they recommend