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Historic Preservation - Technical Procedures

Spectitle:

Dutchman Repair Of Marble

Procedure code:

0445522R

Source:

National Capitol Region Specifications

Division:

Masonry

Section:

Marble

Last Modified:

07/30/2013

Details:

Dutchman Repair Of Marble



DUTCHMAN REPAIR OF MARBLE


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on repairing severely
         cracked marble blocks using dutchman repair.  This
         procedure is also appropriate for large spalls in marble.

    B.   For guidance on making other marble repairs, see 04455-
         03-R, 04455-04-R, 04455-05-R, 04455-08-R, 04455-20-R and
         04455-21-R.

    C.   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).

1.02 REFERENCES

    A.   American Society for Testing and Materials (ASTM)
         www.astm.org         

1.03 SUBMITTALS

    A.   Product Data:  Submit manufacturer's product data for
         epoxy adhesives or resins, including mixing instructions
         and precautionary handling instructions.

    B.   Samples:  Submit samples of marble dutchman units.
         Include full range of colors and textures required to
         match existing stone.  Submit samples of stainless steel
         pins for patching.
   
1.04 QUALITY ASSURANCE

    A.   Qualifications:  

         1.   Contractor performing the work shall have a minimum
              of 5 years experience in masonry restoration work
              of the type described for this project.

         2.   If requested by the Owner, furnish a statement of
              the experience and qualifications of the firm and
              of the key personnel who will work on this project.
              Include the names and addresses of successful
              projects completed, and for each, the name and
              address of the owner and the architect.

1.05 DELIVERY, STORAGE AND HANDLING

    A.   Packing and Shipping:  Deliver stone materials to the
         project site in undamaged condition.

    B.   Storeage and Protection:  

         1.   Store and handle stone to prevent their
              deterioration or damage due to moisture, extreme
              temperature changes, contaminants, breakage,
              chipping or other causes.

         2.   Do not use pinch or wrecking bars to move or place
              stone.  Lift stone with wide belt slings where
              possible.  Use wood rollers to move stone
              laterally.

1.06 PROJECT/SITE CONDITIONS

    A.   Environmental Requirements:  The work is to be executed
         only when the air and surface temperature is 40 F and
         rising, or less than 90 F.  No pointing or patching is to
         be executed when the temperature is 45 F and falling, or
         when freezing temperatures are expected within 48 hours.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Jahn Restoration Mortars
         www.cathedralstone.com
         
    B.  Sika Corporation
         usa.sika.com
         
2.02 MATERIALS

    A.   Marble for replacement marble pieces and dutchman repairs
         to match existing marble type, color and finish,
         complying with ASTM C503.  Size of replacements and
         dutchman pieces shall be as required by field conditions.

    B.   Reinforcement/Anchors:  Stainless steel type 302/304 3/8"
         in diameter threaded rods, length as required.

    C.   Cementitious patching material such as "M70 Stone
         Restoration Mortar" (Jahn Restoration), or approved
         equal.

    D.   Epoxy grout: High-modulus, low viscosity, high strength
         epoxy grouting/sealing/binder adhesive such as "Sikadur
         35, Hi-Mod LV" (Sika Corporation), or approved equal.

    E.   Clean, soft cloths


    F.   Clean, potable water

2.03 EQUIPMENT

    A.   Stiff fiber bristle brushes

    B.   Stiff wire bristle brushes

    C.   Chisel

    D.   Hammer

    E.   Trowel

    F.   Spray bottle

    G.   Masonry drill


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:  Protect existing adjacent materials during
         the execution of the work.  Provide necessary protection
         and conduct work procedures to avoid damage to doors,
         windows, flashing, roofing and other existing material
         assemblies.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Carefully remove loose stone fragments.  Reuse all pieces
         of spalled stone which are in sound condition without
         serious cracks or flaws.  

    B.   Clean any exposed metal anchors of all corrosion by
         scraping and brushing with a stiff wire bristle brush.
         Replace any unsound anchors as necessary with new
         stainless steel anchors of approximate size and shape to
         match existing. Bed new anchors in epoxy grout.

    C.   For resecurring small fragments, see 04455-21-R for
         guidance.

    D.   For larger fragments, square off the portion of spalled
         stone for replacement with dutchman repair.  Remove dust
         and debris from cavity and fragments using a stiff fiber
         bristle brush.  

    E.   Fit the dutchman for size.  

    F.   For dutchman larger than 4" by 4" by 1", additional
         reinforcement may be required.  

         1.   Drill holes (size determined by size of
              reinforcement selected) into both the sound stone
              and the dutchman.  

         2.   Inject adhesive into the holes and set stainless
              steel pins into the holes.

    G.   Coat abutting surfaces of the stone with epoxy adhesive,
         and secure the stone dutchman in place until the adhesive
         is cured.

    H.   Clean any residual adhesive from the edges using a clean
         soft cloth.  Wet the stone with clean, potable water and
         fill any chipped areas and edges with patching mortar.
         Avoid featheredging.  Tool surface level with surrounding
         stone.  Keep mortar damp (80%-90% RH) for 72 hours or
         until cured.

                         END OF SECTION
 


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