REPAIRING SMALL HOLES AND CRACKS IN WOOD FLOORS


PART 1---GENERAL

1.01 SUMMARY

     A.   This procedure includes guidance on filling small holes
          and surface cracks in wood floor boards and filling
          cracks between wood floor boards.

     B.   Cracks the thickness of a dime between floor boards is
          not uncommon.  In fact, plank boards may expand and
          contract 2-1/2 times that distance.

     C.   Cracks can develop between boards from what is known as
          compression shrinkage or compression set.  As the wood
          absorbs moisture, the floor boards swell.  For those
          boards that swell beyond their allowable range, the
          boards compress against one another and, sometimes,
          become damaged.  As the moisture level drops, the boards
          shrink and a gap develops between the boards.

     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).

1.02 DEFINITIONS

     A.   A wooden floor surface can be either a series of
          connected planks or parquet (small wood pieces arranged
          in decorative patterns). The wood used is either plain
          sawn or quarter sawn. Plank flooring, the more common
          type, is assembled by joining: butt joint, tongue and
          groove, shiplap, doweled, spline. Wood floors are usually
          secured to the under structure by countersinking nails,
          blind-nailing, or screwing and plugging.


PART 2---PRODUCTS

2.01 MANUFACTURERS

     A.   Abatron, Inc.
          5501 95th Ave.
          Kenosha, WI  53144
          800/445-1754 or 414/653-2000

2.02 MATERIALS

     A.   Commercial wood putty, colors-in-oil or oil stain pigment
          to color putty to match (Abatron, Inc., Allied Resin
          Corp., or approved equal) - available in wood tones

     B.   Wood glue to reattach splinters

     C.   Sandpaper

     D.   Sawdust

     E.   Varnish

     F.   Shellac

     G.   White wood glue

     H.   Tissue paper

     I.   Calcined magnesia

     J.   Strips of cloth, grey felt weatherstripping or varnished
          hemp, marine caulking compound

     K.   Linseed oil

     L.   Wood for shims (do not use shingles, they lack
          compressive strength)

     M.   Strips of wood for nailing to underside of floorboards or
          for filling cracks between boards

2.03 EQUIPMENT
     
     A.   Small putty knife

     B.   Brush or sponge to spread pigment

     C.   Hammer

     D.   Nails 

     E.   Screwdriver

     F.   Stiff bristle brush

     G.   Vacuum


PART 3---EXECUTION

3.01 EXAMINATION

     A.   Inspect for the signs of decay or insect infestation such
          as mold, fungus, bore holes, and sawdust piles.

3.02 ERECTION, INSTALLATION, APPLICATION

     A.   For Small Holes and Surface Cracks:

          1.   Fill with commercial wood putty:

               a.   Stain the putty to match the floor by using
                    either colors-in-oils or the settled pigment
                    from the bottom of the stain can. 

               b.   When staining putty to match wood, it is
                    better to go darker than the wood rather than
                    lighter. 

               c.   When filling a hole or crack, add filler in
                    layers and allow drying time between layers.

          2.   If a floorboard is splintered, glue the splinter
               down and fill the crack.

          3.   If damage is such that it cannot be successfully
               filled and the board is relatively easy to remove,
               turn the board over rather than replacing it.  The
               new surface should be sanded to match surrounding
               boards and may need to be shimmed to make it level
               with the existing surface.

               NOTE:  THE FEASIBILITY OF THIS METHOD OF REPAIR
               WILL DEPEND UPON THE ORIGINAL INSTALLATION SYSTEM
               AND THE APPEARANCE OF THE UNDERSIDE OF THE WOOD
               FLOORING.

     B.   For Cracks Between Floorboards:  In general, it is best
          to leave cracks between boards alone.  Gaps often
          diminish as the boards expand in more humid seasons. 
          However, there are several methods for filling cracks
          between floor boards:

          1.   If small, they can be covered with a new floor
               finish.  If the underside of the floorboards are
               exposed, nail strips of wood to the underside of
               the crack.

          2.   Fill with a paste filler (made by user):

               a.   Mix sawdust with varnish, shellac or white
                    glue, or

               b.   Mix tissue paper, glue size, and calcined
                    magnesia to a mass like putty.

               c.   Press mixture into crack using putty knife and
                    finish smooth so it is level with the floor
                    surface.

          3.   Fill with a fibrous filler (made by user):

               a.   Soak cloth strips in linseed oil or glue, or
                    use strands of hemp rope (grey felt
                    weatherstripping may also be used, but is not
                    as stainable as hemp rope).

               b.   Pack cloth strips or strands of rope (in
                    layers, if necessary) into the crack using a
                    screwdriver or putty knife.

               c.   If desired, stain the filler material to match
                    the floor.

          4.   Fill with caulking compound:

               a.   If the floor is to be painted, use marine
                    caulking compound to fill the crack. It will
                    expand and contract with the wood and the
                    paint will hide the color difference.

               b.   Carefully mask the area before caulking.

               c.   Fill crack using a caulking gun or similar
                    injection device.  It is best to fill the
                    crack at mid-cycle (in Spring or Fall).

               d.   Finish the surface level with the floor.

          5.   Fill with a thin strip of wood:

               NOTE:  This option is not ideal because it
               reintroduces the potential for compression problems
               resulting from wood expansion and contraction. 
               However for large cracks that are hazardous:
          
               a.   Thoroughly clean the opening of dirt and
                    debris using a stiff bristle brush and vacuum.

               b.   Slip a thin strip of wood into the crack.
                    Match the depth of the surrounding floor and
                    stain to match. 

               c.   Nail or glue the strip to only one side of the
                    crack to allow for expansion and contraction.

     C.   In extreme cases, the floorboards will have to be taken
          up and reinstalled (see 09560-01-R, "Replacing Damaged
          Floorboards" for guidance).

                              END OF SECTION