Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

Treating Rising Damp By Injecting Chemical Dampproofing

Procedure code:

0715001R

Source:

Prosoco, Inc. - Kansas City, Ks

Division:

Thermal And Moisture Protection

Section:

Dampproofing

Last Modified:

02/24/2012

Details:

Treating Rising Damp By Injecting Chemical Dampproofing



TREATING RISING DAMP BY INJECTING CH= EMICAL DAMPPROOFING


DAMPPROOFING OF AN HISTORIC BUILDING IS CONSIDERED AS THE LAST
RESORT BECAUSE SUCH WORK CAN CAUSE IRREVERSABLE DAMAGE TO THE
BUILDING.  BEFORE PROCEEDING WITH SUCH WORK TRY REGRADING AT THE
BASE OF THE STRUCTURE, REPAIRING UNDERGROUND DRAINAGE SYSTEMS, OR
ADDING OR INCREASING VENTILATION.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on treating rising damp
         in masonry walls by installing a chemical dampproof
         course.

    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 Precaution= s

         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).

1.02 DEFINITIONS

    A.   Rising damp - the upward capillary migration of ground
         moisture through porous masonry walls.  

         1.   Rising damp may result from the presence of below-
              grade membranes applied to vertical foundation
              surfaces which prevent moisture from leaving the
              masonry through the exter= ior wall surfaces, and
              forcing the moisture to migrate upward to heights
              of three or more feet above the grade line before
              evaporating.

         2.   Rising damp can result in the development of
              numerous other problems, including damp patches on
              walls, unhealthy living conditions, fungal growth,
              increased heat losses, and staining and
              deterioration of interior finishes, the masonry
              surface and the basic structure of the building.

    B.   Dampproof course - a physical barrier (traditional= ly
         high-fired brick, lead sheets, slate, or bitumen
         material) which is usually inserted approximately six
         inches above the natural ground level during construction
         to prevent the condition of rising damp.=

         1.   These materials may eventually fail due to poor
              installation or deteriora= tion over the years.

         2.   Reinstallation of a mechanical dampproof course is
              an expensive and disrupti= ve process.  Such a solid
              horizontal barrier is difficult to achieve in
              rubble or cavity walls.
    C.   Chemical dampproof course - A specially formulated water
         repellent designed for either low pressu= re injection or
         gravity feed into holes drilled at regul= ar intervals.

         1.   The fluid impregnates the masonry, migrates through
              the capillaries, and forms a chemical
              water-repellent barrier by lining the pores of the
              masonry, and prevents the moisture from migrating.

         2.   The barrier interrupts the migration of water
              through natural capillary action.

         3.   Chemical dampproofing is less costly, quicker, and
              involves far less disturb= ance to the building than
              mechanical dampproofing.<= br>
         4.   In Europe, siliconate resins have been used in
              chemical dampproofing and have proven effective in
              controlling rising damp for periods of 10 or more
              years, provided there are no unusual ground water
              conditions or contaminants and provided there are
              no highly alkaline mortars (as in repair work).


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   ProSoCo, Inc.
         755 Minnesota Avenue
         P.O. Box 1578
         Kansas City,  KS  66117
         800/255-4255 or 913/281-2700

         Request Tech Bulletin 683-1 and Conserva= re Dampcourse
         Fluid Product Data.

2.02 MATERIALS

    A.   Latex-siliconate, such as "Conservare Dampcou= rse Fluid"
         (ProSoCo, Inc.), or approved equal; or silicone solutions
         in organic solvent, or aluminum stearate= s.

2.03 EQUIPMENT

    A.   Infusion reservoir bottles and tubes.

    B.   Low pressure injection equipment.

    C.   Electric drill with 1/2" to 3/4" diameter diamond masonry
         bits


PART 3---EXECUTION

3.01 PREPARATION

    A.   Surface Preparation:

         1.   Remove exterior and interior finishes only as
              required to expose masonry walls for treatment.

         2.   Remove interior plaster damaged by hygroscopic
              salts to a height of 18" above the maximum level of
              rising damp.

         3.   If recommended by chemical manufacturer and RHPO,
              grout large voids in cavity walls within damp zone.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Drill 1/2" - 3/4" diameter holes at six to eight inch
         intervals on one side of the wall only.  

         1.   The more porous the masonry, the further apart the
              holes may be placed.  

         2.   Holes should be placed within mortar joints as much
              as possible.  

         3.   Depth of holes shall be one-ha= lf to three-quarters
              the depth of the wall.

         4.   For walls over 18" thick drill holes into both
              sides of the wall to ensure even penetration of
              dampproof chemical.

    B.   Installation of dampproof liquid - Gravity Infusio= n
         Method:

         1.   Fill infusion cups with liquid and allow liquid to
              flow into holes.

         2.   A minimum of 2=AB quarts of liquid will be required
              per 36 lineal inches of a 10-inch thick wall.

    C.   Installation of dampproof liquid - Pressure Inject= ion
         Method:

         1.   Set pressure of injection equipment to provide 50
              to 100 psi.

         2.   Attach hoses to pump and inject dampproof course
              liquid in stages, or as recommended by
              manufacturer.

         3.   Pump liquid in 4-inch to 6-inch stages, allowing
              each stage to cure accord= ing to manufacturer's
              instructions before pumpi= ng in next stage.

    D.   Allow initial dry out period of approximately fourteen
         days before plugging injection holes with sand/cement
         mortar colored to match the existing wall surface.  For
         guidance on repointing mortar joints see 04211-07-S and
         04520-02-R.

                         END OF SECTION