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Historic Preservation - Technical Procedures

Spectitle:

Removing Soluble Salts From Limestone

Procedure code:

0446004R

Source:

Hsr - Federal Bldg/P.O., Wash, Dc - Bldg Conservation Tech

Division:

Masonry

Section:

Limestone

Last Modified:

10/26/2012

Details:

Removing Soluble Salts From Limestone



REMOVING SOLUBLE SALTS FROM LIMESTONE USING A POULTICE


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing soluble
         salts from limestone.

    B.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

    C.   For general information on the characteristics, uses and
         problems associated with limestone, see 04460-01-S.


PART 2---PRODUCTS

2.01 MATERIALS

    A.   Distilled water

    B.   Paper pulp made by boiling good quality blotting paper
         with distilled water and beating it until completely
         disintegrated and cellulose fibers mat together to form
         a pulp

2.02 EQUIPMENT

    A.   Stiff bristle brushes (non-metallic)

    B.   Vacuum


PART 3---EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

    A.   Clean stone of all debris, dust, oil, salt crystals, etc.
         by brushing with a stiff fiber bristle brush or by
         vacuuming.

    B.   Thoroughly wet stone with clean, clear water just prior
         to applying poultice.

    C.   Apply wet paper pulp (soaked in distilled water) to the
         stone completely covering and concealing all voids and
         surfaces.

    D.   Keep pulp in position for three weeks or until completely
         dried and removed easily.

    E.  After carefully removing the dried pulp, brush or vacuum to remove all salt crystals formed on
         stone surfaces.

    F.   Apply fresh pulp as described in Section B through D
         above.

    G.   Brush or vacuum to remove all salt crystals formed on
         stone surfaces.

    H.   If high concentrations of soluble salts remain in the
         stone, repeat applications of poultice.

                         END OF SECTION
 


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