[laurence]

I recently had a clay brick/pavers patio put in, laid in dry sand. The area is shaded and we get some rain/thunderstorms from time to time (US Northeast) and a lot of humidity.

It's been 2 months now that the patio is complete, I don't think I have seen it completely dry yet, it remains damp !! It is now even molding on the surface.

I am wondering if clay pavers are not supposed to be used in my area, or if the patio was not done correctly.

Any thoughts would be helpful. Any idea on what to do now would be greatly appreciated.

[Stonehenge]

When you say "completely dry", do you mean there's standing water on the patio, or just that the pavers are holding some moisture?

A sand base is going to wick away water faster than just about anything, so if you're having moisture problems, it most likely has to do with the location. That being said, I don't think a different choice in materials would lead to a different outcome.

If shade is causing the problem, a reduction in shade will be the solution, be that limbing up trees or altering some other aspect of the landscape to increase sun exposure and possibly allowing breezes to blow in.

[Bill Schwab]

My experience with clay is that in shaded areas, they are going to hold in moisture more so than concrete. Clay has a different chemical composition then concrete, and, it will produce efflouressence faster than concrete, and, there will come a time when the process stops and it will develope a sheen. Other than coloring, I am not at all a fan of clay pavers. Give them soem time to leach out the stuff they need to and just be patient. After a few years they should be fine,.

[Stonehenge]

That's a good point - what you're seeing might be efflouresence, not mold. If it looks like an elongated white circle (or something thereabouts) that was drawn in chalk, it's efflouresence.

[PSUscaper]

I'm not sure, but doesn't the type of clay paver used have some effect??? now, there are a lot of companies making clay pavers, but you still run across a few people using those HD specials that break when you walk across them. I always noticed that they seem to hold a lot of moisture as they are more porous than others because they are just about hollow inside it seems.

Besides that, reducing the shade would be the only real solution.

[laurence]

Thank you everyone for responding.

There is no standing water on the patio. It is just that the pavers retain a lot of moisture and remain damp / their color remain dark as when wet / does not dry out. We've just had two straight weeks of hot weather with no rain and they are still damp.

I do not think it is efflourescence because it is not white but black, black ink stains kind off. I can tell from the smell that it is molding, also moss is developing in between pavers.

The brick manufacturer is redland brick.

So I guess we'll be trimming trees in the fall then. Could anybody recommend the best way to clean the pavers from mold ? Should I use a power washer ? some chemicals ???

Again thank you for your help !!

[Bill Schwab]

Pressure washer and scrub with bleach. Just wear old cloths unless you want to look like a modern day hippie after you finish..

[GLAN]

Use a bleach water mix....try 10% - 20% bleach, increase if you need to.

Keep in mind that the bleach will make the surface slippery till you have washed it completely clean

[agla]

It is the pourosity of the brick and how it was made. Are these paving bricks, or just bricks used as paving?

I have never seen efflourescence on clay bricks.

[Stonehenge]

I don't know if Pine Hall has a presence on the east coast, but that brand of clay pavers can get efflouresence aplenty.

[Paul]

Here we refused to install Clay pavers because of the call backs due to efflorescence.