How To Clean Pavers With Polymeric Sand

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 16th, 2010 7:43 pm

How to clean polymeric sand joints in patio?

The patio was not sealed and the sand joints are becoming dark with moss in some spots, not the nice bright sand color it was at first. Anyhow know how to restore the sand color prior to sealing?

Mar 16th, 2010 8:02 pm

Ukisuperstar: Member; Oct 8, 2007; 420 posts; 11 upvotes

Mar 16th, 2010 8:02 pm

Going to have to re-sand the patio, either pressure wash with detergent or even water and then re-sand with new polymetric sand. Best results this way, have done this way before.

...

Mar 16th, 2010 8:07 pm

stuntman: Deal Addict; Nov 12, 2006; 2968 posts; 78 upvotes

Mar 16th, 2010 8:07 pm

Not everything can be perfect...maybe it is good the way it is....that stuff has silica in it...a level 1 hazard as per WHIMS

Mar 16th, 2010 9:09 pm

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 16th, 2010 9:09 pm

Ukisuperstar wrote: ↑Going to have to re-sand the patio, either pressure wash with detergent or even water and then re-sand with new polymetric sand. Best results this way, have done this way before.

I can pressure wash it first. Which detergent do you suggest using? To resand, do you have to dig out all the old stuff? Does sealing it work?

Mar 17th, 2010 5:59 am

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 17th, 2010 5:59 am

ticketfighter wrote: ↑I can pressure wash it first. Which detergent do you suggest using? To resand, do you have to dig out all the old stuff? Does sealing it work?

If your polymeric bond has failed (i.e. you're left with a bunch of loose sand between your stones), you can pressure wash to remove old polymeric from between your stones. After everything dries, you can reapply new polymeric, mist it down, and let it harden. I suppose you could seal your entire patio afterwards but I don't know what benefit you're going after in doing so, let alone what product you intend to use. I suppose that a regular resealing would protect the polymeric from future erosion...

If your problem is really just the moss and the polymeric is still in decent shape, you can get rid of the problem with very hot water (or a moss-killer or basic household bleach (diluted), sprayed sparingly and carefully). A few days after that application, you can brush the dead moss off with a stiff broom. Sealing the stones will not keep the moss from growing back, though - nature "intends" moss to grow wherever shade and moisture abound...

Mar 17th, 2010 9:05 am

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 17th, 2010 9:05 am

CaptSmethwick wrote: ↑If your polymeric bond has failed (i.e. you're left with a bunch of loose sand between your stones), you can pressure wash to remove old polymeric from between your stones. After everything dries, you can reapply new polymeric, mist it down, and let it harden. I suppose you could seal your entire patio afterwards but I don't know what benefit you're going after in doing so, let alone what product you intend to use. I suppose that a regular resealing would protect the polymeric from future erosion...

If your problem is really just the moss and the polymeric is still in decent shape, you can get rid of the problem with very hot water (or a moss-killer or basic household bleach (diluted), sprayed sparingly and carefully). A few days after that application, you can brush the dead moss off with a stiff broom. Sealing the stones will not keep the moss from growing back, though - nature "intends" moss to grow wherever shade and moisture abound...

The sand itself has not lost any of its integrity. The problem is that the sand has turned an unattractive black in certain areas that are damp and do not get a lot of sun. In a couple areas there is moss. So, not only do I want the original sand color back, I want it to stay that way. I thought sealing the patio would achieve this.

Mar 17th, 2010 5:53 pm

nielboy: Deal Addict; Jun 12, 2008; 3037 posts; 689 upvotes; Ancaster

Mar 17th, 2010 5:53 pm

When you power wash it, be prepared for a big clean up. My friend re-did his and powerwashed it and had polymeric sand everywhere including up under his soffits. When I heard that I decided to forego on blasting the crap out of mine and just did touch ups where I needed them most.

If you're going to all the trouble though...you should rent one of those tapping vibrating machine they use to tamp down the screening. Just run it over the interlock after you've sanded it and it'll make sure the sand is well worked into the joints. Then you can start misting it after you brush off the excess. You don't need to add detergent to the mix, the water will work just fine.

Also, I wouldn't seal it. It'll just added maintenance and won't help the sand stay in place beyond one season. I tried sealing just the sand grout line between our garage floor and interlock to keep the sand from ending up in the garage all the time. It worked great for the season, but with the winter the sealed sand has all lifted and will have to be re-done now.

Mar 17th, 2010 7:13 pm

dutchca: Deal Fanatic; Jan 27, 2007; 5079 posts; 945 upvotes; Peterborough

Mar 17th, 2010 7:13 pm

Poly sand isn't permanent - it needs to be replaced every couple of years - sounds like yours is due.

Powerwash the majority of it out, let dry. Sweep up the mess. Reapply poly sand. You may want to re-tamp with either a manual or power tamper to get the sand down in all the crevices, then wet and let dry.

Unfortunately, this is not an easy job and takes some time and effort. It is dirty.

Mar 17th, 2010 8:26 pm

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 17th, 2010 8:26 pm

ticketfighter wrote: ↑The sand itself has not lost any of its integrity. The problem is that the sand has turned an unattractive black in certain areas that are damp and do not get a lot of sun. In a couple areas there is moss. So, not only do I want the original sand color back, I want it to stay that way. I thought sealing the patio would achieve this.

You're going to need something that's designed to kill mould. You might want to try diluted bleach in a few small areas and see if you like the results and then take it from there. If the polymeric is still in good shape, don't remove it and I wouldn't seal it as I can see no advantage to you.

Mar 17th, 2010 10:28 pm

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 17th, 2010 10:28 pm

Okay, so if I powerwash the patio, do I need to worry about blasting out the gravel bed below the patio stones? Basically, it's a stonelink patio around my pool. None of the poly sand has lifted, the only problem is it has turned dark and in some spots mossy or 'mildewy'. I thought sealing the patio would also prevent the sand from discoloration.

Mar 19th, 2010 6:38 am

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 19th, 2010 6:38 am

ticketfighter wrote: ↑Okay, so if I powerwash the patio, do I need to worry about blasting out the gravel bed below the patio stones? Basically, it's a stonelink patio around my pool. None of the poly sand has lifted, the only problem is it has turned dark and in some spots mossy or 'mildewy'. I thought sealing the patio would also prevent the sand from discoloration.

I'm sure that sealing will help but keep in mind that last year was an extremely wet one - many people fought mould and mildew. And, let's face it - our patios are outside and things are going to get wet and not all water comes from above...

Are your dark spots closer to the pool? Is your pool salt water, chlorine, bromine,...?

Mar 19th, 2010 1:33 pm

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 19th, 2010 1:33 pm

CaptSmethwick wrote: ↑I'm sure that sealing will help but keep in mind that last year was an extremely wet one - many people fought mould and mildew. And, let's face it - our patios are outside and things are going to get wet and not all water comes from above...

Are your dark spots closer to the pool? Is your pool salt water, chlorine, bromine,...?

It's a salt water pool, but the dark areas are far from the waterline. Basically, the corners of the patio are sloped just slightly to prevent rainwater from flowing into the pool. So, where the water naturally runs to takes longer to dry out. It is these areas that have the problem, pretty much along the perimeter of the patio, especially where the patio meets the retaining walls, which get more shade.

Mar 20th, 2010 9:30 am

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 20th, 2010 9:30 am

ticketfighter wrote: ↑It's a salt water pool, but the dark areas are far from the waterline. Basically, the corners of the patio are sloped just slightly to prevent rainwater from flowing into the pool. So, where the water naturally runs to takes longer to dry out. It is these areas that have the problem, pretty much along the perimeter of the patio, especially where the patio meets the retaining walls, which get more shade.

Okay - we have pretty similar set-ups. Our stones go to the edge of our pool (also saltwater) and, frankly, the polymeric washed out of the poolside crevices within a month or two (it was an absolute disaster). But the polymeric joints in shadier zones in our yard get moss rather than what you seem to be getting (which sounds a lot like mildew). I am led to believe that whatever spores are floating around in your area determine what will thrive in damp areas. We happen to get lichen and moss and you (it appears) get mildew/mould. Last year was the worst year for this we've ever seen - undoubtedly because of the ceaseless rain we experienced (reminded me of the years I lived in Vancouver).

Unlike many caulking products, polymeric sand does not contain any antifungals - once the mildew takes hold, things will blacken up right smartly. I do not know if sealing prevents mildew but it makes since that it would improve your patio's resistance to it.

My advice (again, presuming it's mildew) is to kill it and, in the future, stay on top of it. And, for now, don't bother pressure-washing or sealing it just yet.

Why don't you try this on a small area and see if it's worth doing it further:

mix a solution of 20-30% bleach in water and add about a tbsp of laundry detergent per gallon of this solution
hose down and/or protect any nearby plant material
spray the solution on the mildewed portion of the patio and let it sit for 5-10 minutes
brush the area with a brush or bristle broom
rinse the entire area - including any nearby plant material (sometimes, it's best to do this sort of thing on a cloudy day - so splashed residue doesn't dry too quickly)

If the above works, just spray this when you notice the mildew coming back - should kill it without brushing: just spray, wait 5-10 minutes and hose off.

Let us know what you decide to do and how things work out.

Cheers

Mar 20th, 2010 12:07 pm

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 20th, 2010 12:07 pm

CaptSmethwick wrote: ↑Okay - we have pretty similar set-ups. Our stones go to the edge of our pool (also saltwater) and, frankly, the polymeric washed out of the poolside crevices within a month or two (it was an absolute disaster). But the polymeric joints in shadier zones in our yard get moss rather than what you seem to be getting (which sounds a lot like mildew). I am led to believe that whatever spores are floating around in your area determine what will thrive in damp areas. We happen to get lichen and moss and you (it appears) get mildew/mould. Last year was the worst year for this we've ever seen - undoubtedly because of the ceaseless rain we experienced (reminded me of the years I lived in Vancouver).

Unlike many caulking products, polymeric sand does not contain any antifungals - once the mildew takes hold, things will blacken up right smartly. I do not know if sealing prevents mildew but it makes since that it would improve your patio's resistance to it.

My advice (again, presuming it's mildew) is to kill it and, in the future, stay on top of it. And, for now, don't bother pressure-washing or sealing it just yet.

Why don't you try this on a small area and see if it's worth doing it further:

mix a solution of 20-30% bleach in water and add about a tbsp of laundry detergent per gallon of this solution

hose down and/or protect any nearby plant material

spray the solution on the mildewed portion of the patio and let it sit for 5-10 minutes

brush the area with a brush or bristle broom

rinse the entire area - including any nearby plant material (sometimes, it's best to do this sort of thing on a cloudy day - so splashed residue doesn't dry too quickly)

If the above works, just spray this when you notice the mildew coming back - should kill it without brushing: just spray, wait 5-10 minutes and hose off.

Let us know what you decide to do and how things work out.

Cheers

Thanks, I had planned to try it a bit today, but I think I'll wait till warmer weather returns. With our set up, the installer used mortar for our stone coping around the pool side itself. Every thing else is the poly sand.

Mar 20th, 2010 2:49 pm

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 20th, 2010 2:49 pm

ticketfighter wrote: ↑Thanks, I had planned to try it a bit today, but I think I'll wait till warmer weather returns. With our set up, the installer used mortar for our stone coping around the pool side itself. Every thing else is the poly sand.

Our polymeric is being changed over this summer and this is precisely where we are going: mortar around the pool. You had a very smart installer!

Mar 21st, 2010 3:25 pm

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 21st, 2010 3:25 pm

CaptSmethwick wrote: ↑Our polymeric is being changed over this summer and this is precisely where we are going: mortar around the pool. You had a very smart installer!

Any idea how to safely remove efflorescence from patio stones?

Mar 22nd, 2010 6:08 am

CaptSmethwick: Deal Fanatic; Oct 12, 2007; 6079 posts; 3615 upvotes; Ottawa

Mar 22nd, 2010 6:08 am

ticketfighter wrote: ↑Any idea how to safely remove efflorescence from patio stones?

Muriatic acid - available at Home Hardware or CTC. I did this on our retaining wall last summer. It was an 80' wall and took me ~1 hour. If you're getting this on your stones on the ground, it sounds as if you're pulling moisture up from below. How's your drainage?

Mar 22nd, 2010 10:56 am

ticketfighter [OP]: Member; Jan 27, 2010; 238 posts; 23 upvotes

Mar 22nd, 2010 10:56 am

CaptSmethwick wrote: ↑Muriatic acid - available at Home Hardware or CTC. I did this on our retaining wall last summer. It was an 80' wall and took me ~1 hour. If you're getting this on your stones on the ground, it sounds as if you're pulling moisture up from below. How's your drainage?

The stones on the patio are fine, it's the top coping on my retaining wall.

Mar 22nd, 2010 2:38 pm

nielboy: Deal Addict; Jun 12, 2008; 3037 posts; 689 upvotes; Ancaster

Mar 22nd, 2010 2:38 pm

ticketfighter wrote: ↑Any idea how to safely remove efflorescence from patio stones?

We had efforvescence on our stonework at front of the house and used a wire brush on it and it worked quite well. You could try that before messing with acids.

Mar 22nd, 2010 11:30 pm

stuntman: Deal Addict; Nov 12, 2006; 2968 posts; 78 upvotes

Mar 22nd, 2010 11:30 pm

ticketfighter wrote: ↑Any idea how to safely remove efflorescence from patio stones?

ever hear of google?

anyways....DON'T just go and use muric acid as advised in this thread. Use diluted muric acid or vinegar first. physical removal (brushing as advised in thread) is also an option. Google it.