Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

Resecuring Loose Wall Or Ceiling Plaster

Procedure code:

0921004R

Source:

Hspg Prepared For Nps - Sero

Division:

Finishes

Section:

Gypsum Plaster

Last Modified:

03/31/2014

Details:

Resecuring Loose Wall Or Ceiling Plaster



RESECURING LOOSE WALL OR CEILING PLASTER


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on resecuring loose
         plaster by injecting adhesive behind the loose plaster
         and securing it with plaster washers.

    B.   Plaster is in need of resecuring when sound plaster has
         lost its keys and is floating away from the lath or when
         the plaster and lath are no longer attached to stud or
         joist.

    C.   If wood lath strips are placed too close together, or the
         lath is nailed directly over planks, keys do not form
         properly and the plaster may eventually sag away from the
         lath.  Other factors contributing to sagging plaster
         include wood shrinkage, weight of plaster or broken
         vertical ties (see 09210-06-R).

    D.   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 MANUFACTURERS

    A.  Charles Street Supply Co.
         charlesstsupply.com

    B.  USG Corporation
         usgcorporation.com
         

    C.  TKO Coatings Company, Inc.
         TKOCoatings.com
         

2.02 MATERIALS

    NOTE:  When the common name of a chemical is used on the
    label, it is usually a sign that the substance is not as pure
    as the same chemical sold under its chemical name.  However,
    the grade of purity of the common-name substance is almost
    certain to be adequate for stain removal work, and because it
    is likely to be less expensive, the common-name product should
    be purchased when available.  Common names are indicated by an
    asterisk (*).

    A.   Denatured Alcohol:

         1.   Other chemical or common names include Methylated
              spirit*.

         2.   Potential hazards:  TOXIC AND FLAMMABLE.

         3.   Available from hardware store, paint store or
              printer's supply distributor.

         4.   Denatured alcohol should be a satisfactory
              substitute for ethyl alcohol for stain removing
              purposes.

    B.  Plaster Washers suppliers: Charles Street Supply Co., hardware and building supply 
         firms, internet search, or approve equal.

    C.   Acrylic, laytex or polymer emulsion adhesive (all water-
         based) such as "StrongStik" Construction Adhesive (DAP),
         "Liquid Nails", or approved equal.

    D.   Foam carpet pad

    E.   Wood shingles

    F.   Joint compound such as "Durabond Setting-Type Joint Compound"
         (USG.com), "Krack-kote" (TKOCoatings.com), or
         approved equal.

    G.   Flat head wood screws or drywall screws and plaster
         washers

    H.   Clean, potable water

2.03 EQUIPMENT

    A.   Electric drill

    B.   Bent wire tool

    C.   Vacuum

    D.   Ladder

    E.   1/2 inch plywood

    F.   1 x 2 or 2 x 4 wood braces

    G.   Caulking gun

    H.   Phillips head screwdriver


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Determine the extent of the damage and evaluate work
         requirements and causes before proceeding.  

         1.   Thumping with a finger makes a solid, snappy sound
              on good plaster; it makes a hollow and dull sound
              on loose plaster.

         2.   Gently press the plaster surface with palm of hand
              or with a T-brace made from 2x4s; If plaster moves
              in relation to the studs and lath, then the keys
              are broken; With more pressure, a similar movement
              indicates that the plaster is well keyed to the
              lath, but the lath is loose from the studs.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Resecuring Plaster by Injected Adhesive Bonding:

         1.   Determine the areas of loose plaster and mark them
              out with chalk (see section 3.01 EXAMINATION).

         2.   Ceilings (accessible backside):

              a.   From the backside of the surface to be
                   repaired, drill 1/4 inch injection holes
                   through the lath 3-6 inches apart and at the
                   center of the lath (use a drill stop on the
                   bit to keep from drilling into the plaster).

              b.   Using a bent wire tool and a vacuum, loosen
                   and suck dust out through the injection holes.

         3.   Ceilings (inaccessible backside) and Walls:

              a.   Drill through plaster and lath with holes 3-6
                   inches apart, and if possible, through the
                   center of the lath.

              b.   In walls, break-the plaster open at the bottom
                   of loose areas and vacuum up debris left by
                   broken keys.

         4.   Have 1/2 inch plywood as big as the patch area and
              enough 1x2 wood braces on hand.

         5.   Trim the tip of the caulking-gun cartridge so that
              it fits in the wood-lath holes.

         6.   If selected adhesive has an adhesive primer, squirt
              into pre-drilled holes according to manufacturer's
              instructions.

         7.   If adhesive has no primer, mix 4 parts water, 2
              parts denatured alcohol and 1 part adhesive (water-
              based only).

         8.   Pre-wet both the plaster and lath.

         9.   Inject adhesive into the pre-drilled holes, giving
              the adhesive enough time to flow into the space
              between the plaster and the lath.

         10.  T-brace a 1/2 inch layer of foam carpet padding between the
              plywood and the plaster; Add additional braces as
              necessary or drive screws through washers and wood
              shingles to draw the plaster up against the lath.

         11.  When the adhesive has set, carefully remove the
              plywood (it may need to be twisted gently to break
              the bond).

         12.  Fill holes and/or tape and mud cracks and finish as
              required.

    B.   Resecuring Loose Plaster with Plaster Washers:  Use
         plaster washers (also called repair discs or ceiling
         buttons) to pull sound plaster back up to the lath (when
         the keys have broken), or to pull plaster and lath back
         to the studs or joists.

         1.   If the lath was nailed directly to the joists or
              rafters, find the joists, then measure and mark
              their locations with chalk lines snapped across the
              ceiling.

         2.   From below, drive 1-1/2 to 2 inch gyp-board screws,
              fitted with plaster washers, through the plaster
              and lath up into the joists.  Space  every 4 inches
              on each joist where sagging is apparent, or as
              often as necessary, and 1-1/2 inches from the edge
              of the loose section (only screws that hit lath
              will hold).

         3.   Tighten the screws gradually all along the edge.

         4.   Patch the holes with spackling or joint compound
              and finish with a skim coat of joint (taping)
              compound.

3.03 ADJUSTING/CLEANING

    A.   Remove all rubbish and debris caused by plastering work.

    B.   Clean all affected surfaces of room and furnishings to
         their prior condition.

                             END OF SECTION
 


wall plaster, ceiling plaster, loose wall plaster, loose ceiling plaster, failing ceiling plaster, plaster repair, securing loose plaster