The Building Code Compliance Office

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The Building Code Compliance Office

• Preservative Treated Wood
• Discussion
• Moderated by
• Michael L. Goolsby, RRC

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What is Pressure Treatment?

• Pressure treatment is a process that forces
  preservatives into the wood.
• Wood is placed inside a closed cylinder then
  vacuum and pressure are applied to force the
  preservatives into the wood.
• The preservatives help protect the wood from
  attack by termites, other insects, and fungal
  decay.

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2326.2.5 The expression "pressure treated wood"
refers to wood meeting the retention, penetration
and other requirements applicable to the species,
product, treatment and conditions of use in the
approved standards of the American Wood
Preservers Association (AWPA). Quality Control
Program for Softwood Lumber, Timber and Plywood
Pressure Treated with Water-borne Preservatives
for Ground Contact Use in Residential and Light
Commercial Foundations for the American Wood
Preservers Bureau.
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Some Precautions

• Wear a dust mask and goggles when cutting or
  handling treated or untreated wood.
• Wear gloves when working with treated wood.
• After working with wood, wash exposed areas
  thoroughly.
• Do not burn pressure-treated wood.
• Wash work clothes separately from other household
  clothing.
• Pressure-treated wood should not be used where it
  may come into direct or indirect contact with
  drinking water.
• Do not use pressure-treated wood in circumstances
  where the preservative may become a component of
  food, animal feed, or beehives.
• Do not use pressure-treated wood for mulch.

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What is the AWPA?

• American Wood Preservers Association
• Wood construction shall be in conformance with
  the tolerances, quality and methods of
  construction as prescribed by the standards in
  Chapter 23 and 35 of the Florida Building Code.
• Preservative treated wood must comply with the
  applicable standard.

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Commodity Standards in the Code

• AWPA C2 Lumber, Timbers, Bridge Ties Mine Ties
  Pressure Requirements.
• AWPA C9 Plywood - Pressure Treatment.
• AWPA C31 Lumber Used Out of Contact With the
  Ground and Continuously Protected From Liquid
  Water-Treatment by Pressure Processes

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When is Treated Wood Required?

• 2326.2.1 All wood used in areas of building or
  structures where the climatic condition is
  conducive to deterioration which would affect the
  structural safety shall be treated in an approved
  method with an approved preservative or shall be
  of an approved durable species.

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• 2326.2.2
• All wood in contact with or embedded in the
  ground that supports of permanent structures
  shall be approved pressure treated wood suitable
  for ground contact use.
• EXCEPTIONS
• Naturally durable wood or pressure treated wood
  may be used in contact with the ground for
  support of structures other than buildings and
  walking surfaces.
• 2. Untreated wood may be used for supports where
  entirely below water level and continuously
  submerged in fresh water.

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2326.2.3 Sleepers and sills on concrete slabs in
contact with the ground, wood joists and the
underside of wood structural floors without
joists less than 18 inches (457 mm) above ground
or wood girders less than 12 inches (305 mm) from
exposed ground within the crawl space under
buildings, shall be treated in an approved method
with an approved preservative, or shall be of an
approved durable species.
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2326.2.4 All wood not separated from and/or in
direct contact with concrete masonry, including
sills, sleepers, plates, posts, columns, beams,
girders and furring shall be treated in an
approved method with and approved preservative,
or shall be of an approved durable species.
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What are Naturally Durable Wood Species?

• 2326.2.6 The expression "durable wood" refers to
  the heartwood of the following species with the
  exception that an occasional piece with corner
  sapwood may be included if 90 or more of the
  width of each side on which it occurs is
  heartwood
• Decay resistant Redwood, Cedars, Black Locust.
• Termite Resistant Redwood, Bald and Eastern Red
  Cedar.

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The sapwood is live wood and its main job is to
carry water from the roots to other parts of the
tree. The heartwood is dead wood, but it used
to be live sapwood. The heartwood's main job is
to provide support for the tree. Heartwood also
helps the tree by being resistant to insect
attacks and decay.
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Classifications of Preservatives

• Water Based
• Oil Based

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Water Based Preservatives

• Chromated Copper Arsenate (CCA)
• Ammoniacal Copper Zinc Arsenate (ACZA)
• Alkaline Copper Quat (ACQ)
• Ammoniacal Copper Citrate (CC)
• Copper Azole (CBA)
• Borate (SBX)
• Wood treated with waterborne preservatives is
  typically used in residential, commercial and
  industrial building structures.

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Oil Based Preservatives

• Creosote
• Pentachlorophenol
• Copper Naphthenate
• Creosote is primarily used for treating railroad
  ties, guardrail posts, and timbers used in marine
  structures. Oil-borne (penta) is most often used
  for treating utility poles and cross arms.

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Required Retention of the Preservative Solution

• Retention level refers to the amount of
  preservative that remains in the wood after the
  treatment process is complete.
• It is measured on a weight basis and is typically
  expressed as pounds of preservative per cubic
  foot (pcf) of wood.
• There are a number of typical retention levels
  available.

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For Above Ground Use

• For wood not in contact with the soil.
• 0.25 pcf. For ACQ and CCA.
• 0.20 pcf. For CBA
• 0.28 pcf. For SBX effective against Formosan and
  subterranean termites.
• 0.17 pcf. For SBX effective against subterranean
  termites.

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Ground Contact

• Wood in contact with the soil.
• 0.40 pcf. For ACQ and CCA
• 0.41 Pcf. For CBA
• Borates may not be used in ground contact or
  direct contact with water.

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Chromated Copper Arsenate

• Been used for decades as the primary preservative
  treatment for wood.
• As of 12/31/03 industry voluntarily ceases to use
  CCA.
• There is no ban on the use off CCA as stocks
  remain.
• With the retirement of CCA alternate treatments
  will step up quickly.

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Why is CCA Being Discontinued?

• Negative publicity focused on the use of arsenic.
• Possible leaching of arsenic.
• Arsenic functioned as an insecticide.

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Will CCA Still be Manufactured?

• Will still be produced for industrial, highway
  and agricultural uses.
• Poles, piles, guardrail posts and wood used in
  salt water exposures.

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New Generation of Preservatives

• Alkaline Copper Quat (ACQ-B)
• Achieves durability levels equivalent to CCA.
• Alkaline Copper Quat (ACQ-D)
• Doesnt use ammonia as a carrier.
• Copper Azole-Type A (CBA-A)
• Contains copper and boron. (Wolmanized Natural
  Select)
• Borate Oxide (SBX)
• Non-Toxic water soluable.

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ACQ

• Main ingredient is copper.
• Copper acts as the preservative and permanently
  binds with the wood.
• Quats are used as biocides controlling fungi and
  insects.
• May be more corrosive to metal fasteners, anchors
  and connectors than CCA.

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ACQ

• Does not contain arsenic or chromium
• Provides long term protection from rot, decay and
  termite attack
• For use in above ground, ground contact and fresh
  water immersion applications
• Can be used in residential, commercial and
  industrial applications
• Offers a wider selection of timber species
• Easily painted or stained

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Borates (DOT)

• Disodium Octaborate Tetrahydrate.
• Borate compounds do not promote corrosion.
• Borates leach out of wood if subjected to liquid
  water.
• Borates are not permitted for decks, use in
  contact with the ground, and other outdoor
  applications.

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Items Containing Boron

• Soaps
• Face lotions
• Make-up
• Contact-lens solutions
• Cotton fabrics
• Motor oil
• Recycled paper
• Porcelain enamel covering sinks, refrigerators,
  and pots and pans

• Laundry detergents
• Eye drops
• Plant fertilizers
• Cosmetics
• Drinking water (boron)
• Wallboard
• Fiberglass, including sporting equipment such as
  surf boards, golf clubs, snowmobiles, and jet
  skis
• Ceramic tiles

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Are the Alternates to CCA More Corrosive?

• Recent studies by Simpson Strong Tie and USP
  Structural Connectors using
• AWPA Standard E12 Standard Method of Determining
  Corrosion of Metal in Contact with Treated Wood.
• ACQ and Copper Azole appear to be more corrosive
  to steel and protective coatings than CCA.

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Simpson Strong Tie

• Recommends SS fasteners, anchors and connectors
  with PT when possible.
• Offer a G185 HDG line of products. Cant predict
  service life.
• G60 galvanized products not to be used with PT
  wood.
• G90 to be used with Sodium Borate (DOT).
• Follow recommendations of the wood treater.

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USP Structural Connectors

• Use as a minimum G185.
• Cant predict service life.
• Stainless steel is the best option.
• Follow recommendations of the wood treater.

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Here is a picture of two straps that were slid
into bundles of ACQ treated lumber and left for
5 weeks in storage.
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Areas of Concern

• Corrosion of anchors, fasteners and connectors in
  contact with
• PT wood in building.
• PT wood blocking and battens in roofing, tile
  fasteners and flashings.
• PT furring strips in dry wall installation.
• Limited test data.

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Code Requirements
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2319.17.2.2.7 Connector plates shall be not less
than 20 gage galvanized steel meeting ASTM A
653/A 653M or A 924/A 924M, and shall be
identified by the manufacturer's stamp.
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2321.5 Anchorage to concrete.
All anchors and related fasteners shall be
galvanized.
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2321.6 Anchorage to wood. 2321.6.1 All anchors
and relative nails shall be galvanized.
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SECTION 2324 HIGH VELOCITY HURRICANE ZONES -
CONNECTORS 2324.2 Nails, bolts and other metal
connectors that are used in locations exposed to
the weather shall be galvanized or otherwise
corrosion resistant.
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2318.1.4.1 Sills and/or base plates, where
provided in contact with masonry or concrete,
shall be of an approved durable species or be
treated with an approved preservative and shall
be attached to the masonry or concrete with 1/2
inch (13 mm) diameter bolts with oversized washer
spaced not over 2 feet (610 mm) apart and
embedded not less than 7 inches (178 mm) into a
grout filled cell of masonry or into concrete.
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SECTION 2323 HIGH VELOCITY HURRICANE ZONES -
FURRING 2323.1 Where the interior of masonry
walls is furred, such furring shall be treated
and firestopped as herein required and shall be
securely fastened to the masonry with not less
than one cut nail in alternate course of block.
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2003.8.4.6 Where aluminum is in contact with
treated wood, wood shall be treated with
pentachlorophenol, 5 percent minimum
concentration, or creosote, or zinc naphthanate,
following the protective measures outlined in
2003.8.4.5.
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2003.8.4.5 Aluminum in contact with wood or
other absorbing materials which may become
repeatedly wet shall be painted with two coats of
aluminum metal-and-masonry paint or a coat of
heavy-bodied bituminous paint, or the wood or
other absorbing material shall be painted with
two coats of aluminum house paint and the joints
sealed with a good quality caulking compound.
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How to Determine Type of Preservative Being Used

• 2315.1.10 The quality mark shall contain, as a
  minimum, the following information
• 1. The treating company and plant location.
• 2. The AWPA standard to which the product is
  treated.
• 3. The trademark of an approved inspection agency
  which maintains continued supervision, testing
  and inspection over the quality of the product as
  described in the AWPA standards.
• 4. The preservative used.
• 5. The amount of retention of the chemical per
  cubic foot of wood.
• 6. If applicable, the method of drying after
  treatment
• 7. The purpose for which the wood has been
  treated ground contact, above ground or
  foundation.