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Re: Waterstops, and waterproofing

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I won't go to the extent of saying that water stops are not necessary. They can cause problems, no doubt, but by and large, the contractor is the problem.

Most small time contractors (read lowest bidder or cheap) are not good at their chosen trade. Instead of talking to the engineer about ways to do a better installation, they bad mouth the design and finish a shoddy job.

Some engineers are also at fault, for not detailing the joint properly. For instance, tt will be a heck of a problem to place a waterstop in a 6" thick concrete with a mid-layer reinforcement or to place one in a 8" thick concrete with two layers of reinforcement! The success of a good job depends on selecting a suitable type and shape of waterstop and proper detailing of the joint. There are success stories.

Rajendran

Mark Gilligan <m_k_gilligan(--nospam--at)yahoo.com> wrote:
I have come to the opinion that water stops are not
only generally not necessary but they can cause
problems.

The only place that I would consider a waterstop is
where you had two pieces of concrete that were allowed
to move and where you needed to retain water. Even in
this case I would plan for some leakage. An example
of this was the connection of underground subway
tunnels that were connected to the station.

If the reinforcement continues through the joint then
you should expect cracks no larger than would occur
away from the construction joint. Thus why not use
the same strategy to control water that you use on the
rest of the wall. Some strategies include bentonite,
zypex, or a membrane that can tolerate the expected
cracks. If you feel you must do something at the
construction joint consider the bentonite strips
placed in the construction joint.

The problem with water stops is that they get in the
way of reinforcing and can make it difficult to
consolidate the concrete around the waterstop which in
turn can result in voids in the concrete. These voids
can then lead to leaks. I once came across a repair
contractor who loved waterstops. He said that they
always leak thus creating more work for his firm.

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