Dealing With Calcimine Coated Ceilings

Homerepairnet · Joined: 20 May 2007 Posts: 6 Karma: 0 (0)

Dealing with Calcimine Coated Ceilings.

Out here in New England we have older homes
that in the earlier days used lead paint or had
lead mixed in with the oil paints. One of the
biggest problems was “Calcimine” ceilings.
Definition: cal•ci•mine also kal•so•mine n. A
white or tinted liquid containing zinc
oxide, water, glue, and coloring matter, used
as a wash for walls and ceilings.

At first glance, the ceilings look like ordinary latex
or oil painted ceilings whenin fact calcimine is
acidic and if coated over with standard latex or oil
based paint with fail almost immediately. One way
to determine if your ceilings are calcimine is to
check the underside of a paint chip. If it is chalky
more than likely, it is calcimine.

Trying to scrape and “skim coat” (When you use
joint compound to cover the cracks and defects
caused by a failed coating) you will notice the
joint compoundstarting to bubble. The acid in the
calcimine is breaking down the joint compound.
The best way to approach this is to scrape as
much as the loose ceiling as possible. Then seal
the original ceiling (as is) before repairing.

There are products out there that deal with
calcimine directly. One such product is “Cal- Cote”
I have used this product many times. A heavy
coating will seal the ceiling and give you a surface
to work with. Therefore, you can start skim coating
and repairing all the defects after the Cal-Cote is dry.
(Typically allow it to dry over night.)

After you have applied the skim coat to the ceiling
you will need to allow the compound ample time to
cure .Depending on conditions, (How humid is it?) I
would allow the joint compound over night also.
Then when sufficiently cured you can sand (wearing
a mask and goggles) to achieve a smooth finish.

When all sanded, apply another coat of Cal-Cote
and your ceiling should last quite a long time. One
other thing, Cal-Cote is a very thick product. Unlike
a latex or oil, based paint,which will typically cover
300 sq feet per gallon, expect to get about 200 sq
per gallon.

Following these steps will help in fixing
those old calcimine ceilings. You can always ask
your local paint store what type of product they
carry and the coverage rate of that particular
product.
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