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Historic Preservation - Technical Procedures

Spectitle:

Repairing Broken Vertical Ties On A Suspended Plaster Ceiling

Procedure code:

0921006R

Source:

Hspg Prepared For Nps - Sero

Division:

Finishes

Section:

Gypsum Plaster

Last Modified:

02/24/2012

Details:

Repairing Broken Vertical Ties On A Suspended Plaster Ceiling



REPAIRING BROKEN VERTICAL TIES ON A SUSPENDED PLASTER CEILING


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on resecuring a sagging
         suspended plaster ceiling by lifting the sag with heavy
         gauge wire.

    B.   Common causes of sagging plaster include the following:
         
         1.   Wood shrinkage and weight of plaster pull the
              ceiling away from the joists (see 09210-04-R).

         2.   Lath pulling loose from the ceiling joists (see
              09210-04-R).

         3.   Broken vertical ties (applies to this procedure).

    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).


PART 2---PRODUCTS

2.01 MATERIALS

    A.   Lag bolts

    B.   Heavy-gauge wire

2.02 EQUIPMENT

    A.   Ladder

    B.   Wood 2x4s for T-brace

    C.   Phillips head screwdriver

    D.   Electric drill


PART 3---EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

    A.   Determine direction, location, and spacing of nailers
         (they are usually perpendicular to the rafters).

    B.   Dig out all previously patched cracks.

    C.   T-brace and gently lift the sag (it may be necessary to
         remove or cut back the old wood vertical ties).

    D.   From above the ceiling, screw lag bolts into the rafters
         every 24 inches on center in both directions.

    E.   Using heavy-gauge wire, sling the nailers from the bolts
         through the rafters; Double the wire and wrap it around
         the lag bolt.

    F.   Bring it down, threading it between the lath and the
         nailer in a void near a plaster key, and wrap it back
         around the nailer; Twist it tightly around itself.

                             END OF SECTION