Replacing A Damaged Subfloor Under Tongue And Groove Wood Flooring
- Procedure code:
- Hspg Prepared For Nps - Sero
- Wood Flooring
- Last Modified:
REPLACING A DAMAGED SUBFLOOR UNDER TONGUE AND GROOVE WOOD
A. This procedures includes guidance on replacing a damaged
subfloor under tongue & groove flooring.
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 Precautions
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).
A. Replacement subfloor board
C. Wood blocking for board support at joist
D. Hardwood shims (if required)
E. Construction grade plywood for complete subfloor
replacement (thickness to match existing condition)
B. Wide blade putty knives
C. Carpenter's nippers to remove nail heads
D. Hammer for baseboard and finished floor removal
E. Saw to cut damaged subfloor board
F. Drill to make pilot hole for saw
G. Tools for accurate measurement
A. Check for problems caused by decay: Signs of a decayed
subfloor include buckling or discoloration of the
finished floor, a spongy texture underfoot, water stains
on the subfloor as seen from the underside, and general
B. Probe the wood with an ice pick to determine the
existence of rot.
C. Inspect for signs of insect infestation such as mold,
fungus, bore holes, and sawdust piles.
D. Documentation: Photograph existing condition of flooring
including pattern, etc. for ease of reinstallation.
A. Protection: Adjacent surfaces and permanent equipment
must be masked or covered during repair and maintenance.
Coverings must be adhered without adhesive tape or nails.
Impervious sheeting that produces condensation shall not
B. Surface Preparation:
NOTE: THE COMPLETE REMOVAL OF THE FINISH FLOOR MATERIAL
IS ONLY REQUIRED WITH INTERLOCKING FLOOR ASSEMBLIES SUCH
AS TONGUE & GROOVE.
1. Before replacing the subfloor, carefully remove the
baseboard and the finished floor, label and set
aside for reinstallation.
a. As each piece is removed, mark it as to its
original location; during storage, organize by
location to ease reinstallation.
b. Remove shoe molding of baseboard first, using
gentle pressure on a pry bar at nail
locations. Hold gaps open with blocking as
work progresses along the length of each trim
c. Next, remove baseboard, beginning with top
moldings which are often separate from the
broad, flat sections. Remove it like the shoe
molding, applying pressure only at nail
locations until all nails are exposed and the
trim pieces can be removed.
d. To remove nails, pull them out from the back
of the board; cut nail heads first, if
2. When removing the floorboards, find the last board
laid. Remove it and work in reverse of the manner
in which the floor was installed.
3.03 ERECTION, INSTALLATION, APPLICATION
A. Partial subfloor replacement: Cut damaged subfloor board
off at nearest joist. Nail block to joist for new board
1. Carefully measure the new board and do a trial
fitting. Shim or rip as required to level the new
board with the surrounding ones.
2. Facenail the new subfloor board to the joist or the
attached support block.
3. When repair is complete, reinstall finished floor
and baseboards to match historic condition.
B. Full subfloor replacement: If the subfloor warrants
complete replacement, consider 1" construction grade
plywood. It provides a strong and dimensionally stable
subfloor with no squeaks.
END OF SECTION