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Historic Preservation - Technical Procedures
Epoxy Repair For Deterioration And Decay In Wooden Members
Hspg Prepared For Nps - Sero
Wood And Plastics
Epoxy Repair For Deterioration And Decay In Wooden Members
EPOXY REPAIR FOR DETERIORATION AND DECAY IN WOODEN MEMBERS
A. This procedure includes guidance on stabilizing decayed
wood members with epoxy consolidant and filler.
B. Deterioration and decay in wood results from moisture
infiltration, accompanying fungal growth and insect
infestation. Paint, caulk and sealant failures are also
a major cause of wood deterioration.
C. Some sources of moisture may include the original
moisture in green wood, rainwater, condensation, ground
water, piped water, and water released by water-
conducting fungus through the process of decay itself.
D. Epoxy repair may be appropriate if:
1. the piece to be repaired is historically
significant. Epoxy repair makes it possible to
retain most of an original component by selectively
repairing only the damaged area.
2. if the piece is decorative and replacement would be
too expensive or impossible.
E. Epoxy repair may NOT be appropriate if:
1. the piece is a structural member. Epoxy has
adequate compression strength, but is not the best
choice to repair a member in tension. In this
case, replacement is usually a better option.
2. the wood to be repaired is to remain unpainted, as
the epoxy is quite different in appearance than
wood. In this case, the wood should be selectively
3. if the area to be repaired is large, as epoxy
repair can be expensive.
F. 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. Conservation Services
8 Lakeside Trail
Kinnelon, NJ 07405
B. Abatron, Inc.
5501 95th Ave.
Kenosha, WI 53144
800/445-1754 or 414/653-2000
C. Roux Laboratories
5344 Overmyer Dr.
Jacksonville, FL 32205
A. Epoxy consolidant and epoxy filler, both are multiple
part compounds. Purchase by the gallon unless a large
amount of epoxying needs to be done. Use one of the
following, or approved equal:
1. "Con Serv (T) Flexible Consolidant 100"
(Conservation Services): Cures slowly with a 5 to
7 hour application time to allow deep penetration.
Complete hardness is achieved in 3 to 6 days.
2. "Con Serv (T) Flexible Patch 200" (Conservation
Services): A four part putty-like filler; Is not
easy to mix in small amounts; Consistency and
hardness are easily controlled with this material.
NOTE: The products of Conservation Services are
recommended for treatment of thicker wood such as window
sills. Because of its slower curing time, it allows for
deeper penetration into members.
3. "Liquidwood-1" Consolidant (Abatron): Solidifies
in a short period of time.
4. "Woodepox-2" Adhesive Paste (Abatron): A two-part
paste mix; final hardness is determined by varying
the ratio of the two parts. The LiquidWood can be
used as a thinner, but this reduces the flexibility
of the filler.
NOTE: These Abatron products are recommended for use on
smaller members such as window sashes where deep
penetration of consolidant is not required. The quick
drying feature is an advantage for small, but repetitive,
jobs. Abatron carries twenty different types of wood
consolidants with varying degrees of penetration.
B. Oil clay that can be purchased from a hobby store -- used
to keep consolidant from leaking through cracks.
C. Nitril Rubber Gloves (Abatron)
D. Disposable vinyl gloves: Available from drug store or
pharmaceutical supply distributor in 50 count or larger
A. Plastic bottles, like those used for hair dye, to apply
the consolidant; having many on hand is recommended.
Cleaning of the bottles for reuse is possible.
B. Applicator bottles: Available from drug store and sold
for hair dye application usually in 8 fl. oz. size; Also
available in bulk from Roux Laboratories. Roux Color
Applicators lend themselves more easily to cleaning and
C. Rags of different sizes to wipe up spills before epoxy
has a chance to harden, small rags are recommended for
quick one time uses such as wiping off spouts and caps.
D. Thin wooden sticks, approximately 8" long for scooping
out paste and mixing consolidant.
E. Goggles and a respirator for protection from fumes.
F. Putty knives for application of filler
G. Channel lock pliers for opening stuck caps
H. Allen wrench to clean out cap holes
I. Needle nose pliers to pull out hardened epoxy
J. 1/8"x8"x12" Masonite boards for mixing paste filler
K. Carbon dioxide fire extinguisher: Curing epoxy creates
heat that may cause fire
L. Rotary saw
M. Air compressor
O. Stiff bristle brushes
A. Detect rot using the "Pick Test":
1. Insert an ice pick into the wood at a slight angle.
2. Lift the pick out. If the wood splinters in long
pieces, the wood is ok. If the wood snaps where
the pick is being lifted, the wood is decayed.
B. When rot is discovered:
1. Determine the source of moisture infiltration and
a. If rot is only present on the surface, drying
is all that is necessary to stop the spread of
decay and kill off any growth.
2. If source of moisture is unknown, treat the wood
with a preservative.
a. Preservatives are caustic chemicals and should
be handled with care.
b. A particularly dangerous wood preserving
chemical is pentachlorophenol (a.k.a. penta).
CAUTION: THIS CHEMICAL IS CARCINOGENIC AND
ITS USE IS BANNED IN MANY STATES.
3. Preservatives will eliminate fungal growth, but
generally do not restored strength to the
deteriorated wood material.
A. Surface Preparation:
1. Dry affected wood member completely to arrest
further decay. Dry in place if possible -or-
remove the member and keep in a cool dry place
CAUTION: IF THIS PRECAUTION IS NOT TAKEN, THE
EPOXY CAN ACTUALLY TRAP MOISTURE IN WOOD FIBERS AND
ACCELERATE THE DECAY PROCESS.
2. Have all materials at hand before the mixing
3. Label all caps and lids so that a cap or lid is not
placed on the wrong container or it may remain
3.03 ERECTION, INSTALLATION, APPLICATION
CAUTION: AS EPOXIES CURE, HEAT IS PRODUCED. FOR THIS REASON,
EPOXIES SHOULD BE USED IN SMALL QUANTITIES TO DETER EXTENSIVE
HEAT BUILD-UP. CARE SHOULD BE TAKEN WHEN USING EPOXY ON A HOT
A. Repair decayed wood using epoxy wood consolidant:
1. Drill 1/4" or 3/16" holes in affected wood to
receive epoxy consolidant:
a. Drill holes at an angle and spaced
approximately 2" on center in staggered rows.
The top of one hole should line up with the
bottom of the next hole.
CAUTION: BE SURE NOT TO DRILL THROUGH THE
ENTIRE SURFACE FOR CONSOLIDANT WILL LEAK OUT
b. Dam any surface cracks with oil clay so that
epoxy will not leak.
2. Remove sawdust and dirt from drilled holes using
compressed air or stiff bristle brushes.
3. Following manufacturer's instructions, mix a small
amount of the consolidant components (resin and
hardener) together in an applicator bottle. Stir
the mixture thoroughly by hand with a thin stick
for 4 minutes or with a bent coat hanger chucked
into a drill for 2 minutes.
4. Using a large plastic syringe or squeeze bottle and
tube spout, carefully squirt the consolidant into
the pre-drilled holes. Completely saturate the
wood, moving from hole to hole refilling until the
wood can hold no more. More than one application
may be needed.
5. Wipe off any excess consolidant or spills and cover
the treated area to protect until cured as directed
by epoxy manufacturer.
6. If severed pieces need to be re-attached, glue them
in place with a mixture of consolidant and filler.
B. When the consolidant has cured, fill the voids in the
surface with epoxy filler (wood-epoxy putty):
1. Mix the two part epoxy filler following the same
procedures for mixing consolidant in Section 3.03
A.3. above. Mix filler to achieve the consistency
of a glazing compound that can be worked with a
2. Apply the filler to the surface:
a. For large voids, apply filler in 1" thick
layers. This reduces the possibility of
problems associated with heat build-up.
b. Build up filler layers slightly above the wood
surface to allow for planing and sanding
smooth after it has cured.
3. When the filler has cured, sand or plane the
4. Apply a wood preservative to surrounding wood
surfaces and prime and paint the entire surface.
END OF SECTION