1. My new (2 months old), still-unsealed concrete paver bricks
(Cambridge brand with Armortec)have stains on them from where leaves
were laying during a rain storm. Any cheap way to remove them? I know
there are solutions that cost $40 per gallon. I've tried bleach and
laundry detergent with a scrub brush. (The stain didn't come out, but
the rest of the paver was cleaner.) Haven't tried TSP yet.

2. The house is built on a slab on clay soil. Some of the pavers abut
the foundation walls, and there is sand between the pavers and the wall.
Would it be better to replace the sand near the walls with something
waterproof, to minimize moisture getting under the foundation where
there may be freeze damage?

Before installing the pavers, there was a concrete patio slab with a
1/2-inch gap between the slab and the walls. Since the house was built
in 1969, one corner of the patio slab had sunk at least two inches, so
rain ran toward the foundation walls. Despite that, there is no sign of
freeze damage over the 35 years. The new pavers are properly pitched
away from the walls, but they have many more entry points for water
(between each joint) compared to the solid concrete slab.

Thanks,

Ray

"Ray Kostanty"

1. My new (2 months old), still-unsealed concrete paver bricks
(Cambridge brand with Armortec)have stains on them from where leaves
were laying during a rain storm. Any cheap way to remove them? I know
there are solutions that cost $40 per gallon. I've tried bleach and
laundry detergent with a scrub brush. (The stain didn't come out, but
the rest of the paver was cleaner.) Haven't tried TSP yet.

Last fall leaves stained my paver driveway. As you described, stains appear
when the leaves get rained on and plastered to the surface. I did nothing,
and by April this year the stains were gone, washed away by snow and rain.
This fall I'm sweeping the leaves off.

I'm not positive that the PavePrep or other acid cleaners would remove the
leaf stains. Time will, though.


2. The house is built on a slab on clay soil. Some of the pavers abut
the foundation walls, and there is sand between the pavers and the wall.
Would it be better to replace the sand near the walls with something
waterproof, to minimize moisture getting under the foundation where
there may be freeze damage?

Depending on the construction details, you could put a piece of L shaped
flashing up under your siding, lapping over the pavers. Or, you could use
some elastomeric caulk to try and seal the joint. Or, you could remove the
existing sand and replace it with some polymeric sand, which allows less
water to penetrate.

In any case, if the pavingstone surface is correctly pitched to shed water,
you will have little water penetrating the area. Properly installed
pavingstones shed 90% of the surface water. The joint at the foundation is
more vulnerable but in most cases isn't a problem.


Before installing the pavers, there was a concrete patio slab with a
1/2-inch gap between the slab and the walls. Since the house was built
in 1969, one corner of the patio slab had sunk at least two inches, so
rain ran toward the foundation walls. Despite that, there is no sign of
freeze damage over the 35 years. The new pavers are properly pitched
away from the walls, but they have many more entry points for water
(between each joint) compared to the solid concrete slab.

Even though they have more joints, they still shed the great majority of the
water. What water does permeate the pavingstone surface under most
conditions disperses through the drier base and soil without harm. Assuming
the pavinstones were installed properly, and that you have proper drainage
elements in place in adjacent areas, you should be fine.

Will Niccolls
ICPI Certified Installer

Thanks, Will, for the encouragement regarding the leaf stains and the
suggestion for polymeric sand; sounds like just the thing I need. In my
situation, flashing won't work.

Ray


Will Niccolls wrote:
"Ray Kostanty"


1. My new (2 months old), still-unsealed concrete paver bricks
(Cambridge brand with Armortec)have stains on them from where leaves
were laying during a rain storm. Any cheap way to remove them? I know
there are solutions that cost $40 per gallon. I've tried bleach and
laundry detergent with a scrub brush. (The stain didn't come out, but
the rest of the paver was cleaner.) Haven't tried TSP yet.


Last fall leaves stained my paver driveway. As you described, stains appear
when the leaves get rained on and plastered to the surface. I did nothing,
and by April this year the stains were gone, washed away by snow and rain.
This fall I'm sweeping the leaves off.

I'm not positive that the PavePrep or other acid cleaners would remove the
leaf stains. Time will, though.


2. The house is built on a slab on clay soil. Some of the pavers abut
the foundation walls, and there is sand between the pavers and the wall.
Would it be better to replace the sand near the walls with something
waterproof, to minimize moisture getting under the foundation where
there may be freeze damage?


Depending on the construction details, you could put a piece of L shaped
flashing up under your siding, lapping over the pavers. Or, you could use
some elastomeric caulk to try and seal the joint. Or, you could remove the
existing sand and replace it with some polymeric sand, which allows less
water to penetrate.

In any case, if the pavingstone surface is correctly pitched to shed water,
you will have little water penetrating the area. Properly installed
pavingstones shed 90% of the surface water. The joint at the foundation is
more vulnerable but in most cases isn't a problem.


Before installing the pavers, there was a concrete patio slab with a
1/2-inch gap between the slab and the walls. Since the house was built
in 1969, one corner of the patio slab had sunk at least two inches, so
rain ran toward the foundation walls. Despite that, there is no sign of
freeze damage over the 35 years. The new pavers are properly pitched
away from the walls, but they have many more entry points for water
(between each joint) compared to the solid concrete slab.


Even though they have more joints, they still shed the great majority of the
water. What water does permeate the pavingstone surface under most
conditions disperses through the drier base and soil without harm. Assuming
the pavinstones were installed properly, and that you have proper drainage
elements in place in adjacent areas, you should be fine.

Will Niccolls
ICPI Certified Installer