I have been told that
low-voltage step lights can’t be used within 5 feet of the
water’s edge. Is this true, and is it true that there are
some transformers in the industry that are made specifically for
low-voltage lights that are less than 5 feet from the
This issue is still up for interpretation. The code that specifies
the distance of a light from the pool does not differentiate as to
what type of light. In our area, a low-voltage light can be closer
than 5 feet to the water if it is connected to a transformer that
is more than 5 feet from the water and plugged into a GFCI. I
recommend that you check with your local building department to see
how they look at this issue.
In San Diego the setback is actually 10 feet, not 5. The only time
we were able to get around that rule was with a 12-volt
fire-ignition system that required a special inspection and
certification — very expensive and time-consuming.
What is the best waterproofing material to help prevent
efflorescence behind tile and stone on infinity edges?
Efflorescence is the white staining that occurs when natural salts
within the concrete and mortars are pushed out of the concrete by
the water pressure. It is often a slow process that is not
necessarily driven by vessel leakage, but rather by the
permeability of the materials. The plaster is only 99 percent
waterproof, so some water is permeating the plaster, then through
the concrete. Some of the efflorescence originates from the
hydration process of the concrete itself.
The solution is waterproofing, but there is no single
“best” answer, because there are so many options and
variables (e.g., wet-mix vs. dry-mix shotcrete, freeze/thaw
conditions, presence of chlorides, expense, etc.).
I break down waterproofing into three basic categories: integral,
penetrating and topical. Xypex C-1000 admixture is our preferred
integral waterproofing system. It is added to the concrete at the
ready-mix plant, and it forms crystals within the concrete to seal
it up. Because water can’t migrate through the watertight
concrete, it can’t push the loose salts out. Aquafin, Sika,
and other manufacturers have integral products similar to
Penetrating sealers like Aquron or Endur-O-Seal’s HydraLoc
also work well and in the same basic manner as the integral
systems. However, freeze/thaw conditions need to be reviewed
carefully, as well as potential bonding issues with dry-set
or thin-set mortars that may require removal of any waterproof
films left on the substrate prior to applying veneers.
Topical sealers, like Aquafin 1K + 2K/M on the negative (dry) side
and two layers of Aquafin 2K/M on the positive (wet) side, are also
capable systems. As with all products, read everything, call the
manufacturers, and test with mockups if necessary. The Genesis 3
Forum also is a great resource with lots of real experience shared
by many builders.
I also avoid flexible membrane systems (waterborne latex). They are
tricky to use and have resulted in delaminations.
What is the best way to repair a lifted deck caused by
expansive soil or tree roots? I’m looking for a solution
that’s less expensive than replacing the whole
There are no shortcuts for this situation, and a repair will never
match. We have not found a way to keep the existing section of
concrete, which only leaves removal as an option. The amount that
will be replaced is a function of your customer’s budget. A
small budget means that the customer may be willing to accept the
patch. A larger budget will allow for a complete tear-out, or an
overlay to cover up the repair.
The bigger issue is what has been done to eliminate the cause of
the lifting. Tree roots are obvious — remove them. But they
may come back if the tree is still in place. Expansive soil is a
different issue altogether. The main culprit here is probably the
lack of drainage. Homeowners often change the drainage course that
had been installed with the deck, or the drain lines have become
plugged. Make sure that the water can drain away from the edge of
the deck and enter a clear drainage course. Also, be sure the deck
has a seal between the tile or coping. If water is allowed to
penetrate in these areas, you just created a future warranty
problem for yourself.
Why is it important with steel re-enforcement to make
sure that it’s clean of all dirt and debris prior to the
Steel is used to hold concrete together. If the concrete is not in
direct contact with the steel, the steel cannot do its job. A
couple other critical issues with steel are: It must be placed in
the correct location within the structure, and splices should be
the correct length (40 diameters).
I just poured new concrete around a 16-by-36-foot
rectangular pool. It is all new stamped and cantilevered coping.
After we were done, a neighbor sabotaged the skimmer with some of
the leftover concrete from the truck. He lifted the skimmer lid and
shoved in as much concrete as he could. No one knew until the owner
started the pool up and found that one of the skimmers wasn’t
working. I couldn’t figure how all the concrete got into the
skimmer. After digging and blowing out the line I’ve had
enough. I got a power washer and blew out as much as I could. The
line was full and I could not get any further than the elbow at the
bottom of the skimmer. What should I do next?
This is a difficult situation. We had something similar happen and
were ultimately successful using muriatic acid. However, in that
case the concrete was less than a week old when it was discovered.
Pouring straight muriatic acid and letting it sit may break down
what is left in the pipe. The problem will not go away easily
because, once you loosen the piece from the pipe, it probably
will move to the next fitting and cause an obstruction there. If
there is any access from outside the deck to the skimmer line, you
might be able to cut the pipe and chip the concrete from that
direction. Beyond these efforts, which may or may not solve your
situation, you will need to remove the section of concrete and cut
into the pipe to remove the obstruction.
When I design spas, I like to install a couple of jets
into the floor as foot jets. The problem is we get inconsistent
results, depending on how the jets are looped and whether the
plumber properly takes into account the added weight of water at
the bottom of the spa vs. the other bench jets. Sometimes the jets
are not powerful enough, and sometimes they’re too powerful.
Is there some way to plumb these installations to ensure more
The apparent force of the jets depends on the water velocity
through the jet and the amount of air entrained by the
The water velocity part is fairly easy to understand: A higher flow
rate (gallons per minute) through a fixed diameter orifice equals
more velocity; more velocity feels like more power.
The air injection is a little more complicated. It depends on flow
rate and velocity too, but also on the differential pressure drop
across the venturi nozzle. When the jets are located at the floor,
there is more static pressure at the discharge point. Compared to
the wall jets, the floor jets have less differential pressure,
which can reduce the amount of air and the apparent force of the
jet on your feet. It is also possible to have too much water
flowing through the jets, which reduces the air. But the jets may
feel strong because of the high velocity. All of this is further
complicated when the floor jets are hydraulically tied to the wall
jets. Some manufacturers are good about publishing performance data
for the nozzles, and it is wise to design to that criteria.
My recommendation: Always plumb the floor jets on a separate pump
and loop from the wall jets. This way, the relative differential
pressure between the wall jets and the floor jets is eliminated.
Use a variable-speed pump to provide adjustment.
Since there is not only differential pressure, but potentially
significantly different friction loss values between an upper wall
jet manifold and a floor jet manifold, either use a separate pump
for each application, or plumb the manifolds with separate lines.
Based on the assumption you have properly sized your pump and lines
for the total job description, you can adjust the flow via a
three-way valve to compensate for the variation in the two
Is there a sealant that is rated for stone that is set
underwater? All technical documents I’ve ever seen only state
that sealants are for stone that is not submerged.
I’ve had pretty good luck with an Aquron product called 1200
Stone Preservative. But I understand they’re introducing a
new product that’s even better for these applications.
It’s called Invisa-Shield.