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Subject: Storage space with concrete floors

Storage space with concrete floors

From: George W. Adams <cunningham-adams>
Date: Saturday, June 29, 1996
On 28 Jun 96 Mark Ast asks further questions regarding concrete floors

Mark,

I applaud your care.

There are many ways to prevent future problems.  There are two basic
approaches: do everything you can regardless of cost; or determine
what the problems are likely to be, and take the simple steps
necessary to prevent those.  This latter approach is not likely to
be expensive, and should not take much time.  Generally, museums
have better ways to spend their limited funds than on shotgun
solutions.

To be more specific about materials and details, I would need more
facts, including: Where are you located (what is the climate)? How
is the building constructed, and what provisions were made for
foundation drainage? How big is the storage area you are
contemplating?  What are the materials you are storing there, and
what climate extremes can you accept?  What kind of shelving and
shelving loads are you contemplating?  What is the existing HVAC
system?  How long do you plan for the materials to stay there?  What
is your budget?

Yes, generally epoxies are the best waterproofing coatings, but they
will not solve the more common problem, which is atmospheric. They
are expensive to apply well, and unless applied well they will not
be effective.  Plastic sheeting laid on the floor will not be
effective.  We use stand alone electronic climate monitors because
they are cheap, they are accurate, they can be placed in restricted
locations  where the problems are most likely to occur, and they are
easy to tend (they don't need winding, they don't run out of paper
or ink, and the data in electronic form is easier to manipulate than
graphs).  By wicking I mean water transfer by capillary action or
similar.  (Water will creep an astonishing height up a rust coating
on a steel member, for example.)

Expanding on my comments about the interior environment:  If there
is reasonable air movement, the absolute humidity within the space
will be fairly constant throughout.  But the *relative* humidity
will be higher where the air is locally chilled--for example, near a
cold floor.  Even if the air isn't chilled to the dewpoint, the
relative humidity, and thus the moisture content of objects at that
temperature--will be substantially higher than at the warmer center
of the room.  In conservation, significant environmental differences
often occur at subcentimeter scales.  Monitoring conditions in the
middle of a space is rarely interesting.

Per Cullhed (Conservation DistList, Instance: 10:4) is quite right:
evaluate the problem carefully before implementing solutions.  But
despite this shower of advice, do not be fearful.  There is no
inherent reason that concrete floors are bad, and if the structure
is reasonably well built, the preventive measures are not difficult.

We are located in Connecticut, and work throughout the eastern US.
If you are in that sphere and wished, perhaps it would make sense
for me to visit.

Cordially,
George

                                  ***
                  Conservation DistList Instance 10:5
                   Distributed: Monday, July 1, 1996
                        Message Id: cdl-10-5-003
                                  ***
Received on Saturday, 29 June, 1996

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