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Treatment for Condensation on Historic Glass and Storm Sash

The Old House Web

SUMMARY

This procedure includes guidance on cleaning and protecting glazing againstcondensation. This procedure should NOT be used on wood windows with a shellac finish. The alcohol mixture recommended for treating condensation will destroy the finish.

Safety Precautions:

1. DO NOT save unusedportions of stain-removal
materials.

2. DO NOT store anychemicals in unmarked containers.

3. EXCELLENTVENTILATION MUST BE PROVIDED WHEREVER ANY
SOLVENTIS USED. USE RESPIRATORS WITH SOLVENT
FILTERS.

NOTE: SOME OF THE SOLVENTS LISTED ARE KNOWN
CARCINOGENSAND MAY BE BANNED IN SOME STATES.

4. No use of organicsolvents indoors should be
allowedwithout substantial air movement. Use only
spark-prooffans near operations involving
flammableliquids.

5. Provide adequateclothing and protective gear where
thechemicals are indicated to be dangerous.

6. Have availableantidote and accident treatment
chemicalswhere noted.


1.02 DEFINITIONS

A. Condensation in building terms is the process bywhich
water vapor, a gas, changes to aliquid. There is always
water vapor in the air, the amountdepending upon the
local climatic conditions. Within a building, the amount
of water vapor depends upon theamount of vapor generated
by the users. Air has theability to hold water vapor in
accordance with the temperature ofthe air. The higher
the air temperature the more watervapor the air can hold
and vice versa. When the airis saturated it has reached
the dew point. If thetemperature drops, the air can no
longer hold all the water, so theexcess is changed back
into liquid form.

B. Surface condensation occurs on any buildingmaterial
whose temperature is lower than thedew point, but it is
only visible on surfaces which arenonabsorbent, such as
window glass in winter and exposedcold water pipes in
basements in summer (surfaces whichare nonabsorbent.)


PART 2---PRODUCTS

2.01 MATERIALS

NOTE: Chemical products are sometimes sold under a common
name. This usually means that the substance is not as pureas
the same chemical sold under its chemical name. The gradeof
purity of common name substances, however, is usually adequate
for stain removal work, and these products should be purchased
when available, as they tend to be less expensive. Common
names are indicated below by an asterisk (*).

A. Xylol:

1. Any of three toxic,flammable, oily, isomeric,
aromatichydrocarbons that are di-methyl momologues
ofbenzene and are obtained from wood tar, coal
tar,or petroleum distillates; Also a mixture of
xylenesand ethyl-benzene used chiefly as a
solvent.

2. Other chemical orcommon names include Xylene; P-
xylene;1,4-dimethyl benzene.

3. PotentialHazards: TOXIC AND FLAMMABLE.

4. Available fromchemical supply house, hardware
store,paint store or printer's supply distributor.

-OR-

Toluol:

1. A liquid, aromatichydrocarbon that resembles
benzenebut is less volatile, flammable and toxic;
Isproduced commercially from light oils from coke-
ovengas and coal tar and from petroleum, and is
usedas a solvent, in organic synthesis and an
antiknockagent for gasoline.

2. Other chemical orcommon names include Toluene.

3. PotentialHazards: TOXIC AND FLAMMABLE.

4. Available fromchemical supply house, hardware
store,paint store or printer's supply distributor.

B. Glycerin (or Glycerine):

1. A sweet syrupyhygroscopic trihydroxy alcohol
usuallyobtained by the saponification of fats and
usedespecially as a solvent and plasticizer.

2. Other chemical orcommon names include Glycerol;
Glycerylhydroxide; Glycyl alcohol; 1,2,3-
propanetriol;Propenyl alcohol.

3. Potential Hazards: FLAMMABLE.

4. Available fromchemical supply house, drug store or
hardwarestore.

C. Methyl Alcohol:

1. Other chemical orcommon names include Carbinol;
Methanol;Methyl hydrate; Methyl hydroxide;
Methyllicalcohol; Colonial spirits*; Columnian
spirits*;Green wood spirits*; Manhattan spirits*;
Pyroligneousspirit*; Pyroxylic spirit*; Standard
woodspirits*; Wood alcohol*; Wood naphtha*; Wood
spirit*.

2. Potential Hazards: TOXIC AND FLAMMABLE.

3. Available fromautomotive supply distributor,
chemicalsupply house, dry cleaning supply
distributor,drugstore or pharmaceutical supply
distributor,hardware store, paint store, or
photographicsupply distributor (not camera shop).

D. Caulk

2.02 EQUIPMENT

A. Clean cloths for drying

B. Caulking gun


PART 3---EXECUTION

3.01 EXAMINATION

A. Before proceeding with steps to clean and protectglazing
against condensation, firstdetermine the cause and
extent of the problem:

1. Determine the age ofthe structure and of the
glazing.

2. Examine thecondition of the window components.

3. Is glass free ofembedded dust?

4. Check for cracked,broken, chipped, or otherwise
damagedglass.

3.02 PREPARATION

A. Protection: Provide adequate wash solutions(i.e. water,
soap and towels) before startingthe job.

B. Surface Preparation: Remove all oil, dirt,and other
materials from the glass and anymetal framing members by
means of proper solvents (xylol ortoluol).

3.03 ERECTION, INSTALLATION, APPLICATION

NOTE: APPLY TREATMENT EVERY TIME THE GLASS IS WASHED(WINTER,
SPRING, SUMMER, FALL)

CAUTION: DO NOT USE THIS PROCEDURE ON WINDOWS WITH ASHELLAC
FINISH. THE ALCOHOL MIXTURE WILL DESTROY THE WOOD FINISH.

A. Apply mixture of equal parts of glycerin andmethyl
alcohol to the inside of the glasswith a clean cloth.

B. Clean excess solution from glass, frames and sash
promptly.

C. Clean adjacent surfaces if spills have occurred.

D. If storm windows are in place, identify locationof
condensation (interior sash orexterior sash) and make
necessary adjustments to reducecondensation.

1. Sweating on insideof interior sash is the result
ofcold air infiltration around the exterior sash.
Caulkaround exterior sash to eliminate
infiltration.

2. Sweating on theinner face of the exterior sash
indicateswarm air infiltration around the interior
sash. Caulk around interior sash to eliminate
infiltration.

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