media release underlayment plywood

INTRODUCTION The EWPAA has for some time been receiving marketplace feedback about the poor performance of low cost imported underlayment plywood and anecdotal evidence of a significant

INTRODUCTION

The EWPAA has for some time been receiving marketplace feedback about the poor performance of low cost imported underlayment plywood and anecdotal evidence of a significant increase in flooring failures due to the quality of plywood underlayment Underlayment plywood is plywood used under high value strip flooring systems and is usually fixed to a concrete slab with the strip flooring nailed into the underlayment plywood The underlayment plywood’s primary role is to provide substrate into which nails can be fastened however it also fulfils secondary roles in sound attenuation, to stablise the floor by providing a base which minimises hygroscopic movement and at times may be used as a structural element of the floor

Due to the strong marketplace feedback on the poor performance of imported underlayment plywood, the EWPAA was instructed to purchase a sample of imported underlayment plywood and test any claims

of compliance to Australian Standards and ascertain “fitness for use” in the intended underlayment application

To be “fit for use” as flooring underlayment any plywood would need to meet the following criteria

1 Bonding Quality - As a minimum, should be Type B as specified in AS/NZS 2754.1 Adhesives for

Plywood (see Table One)

2 Thickness – Thickness would need to be uniform across the panel to ensure a flat and smooth

floor and mean panel thickness should meet strict limitations

3 Formaldehyde – There are currently no limitations for formaldehyde emissions under the

Building Code of Australia, or any mandatory requirements for emission labelling on products, however as the product is used in confined environments formaldehyde emissions are a serious potential risk to home occupants should emissions be high

4 Lyctid Borer Susceptibility - The product must be free from lyctid susceptible sapwood veneer

This is not only required to ensure that the product is “fit for use” but is also required under Queensland and New South Wales State Legislation Lyctid susceptible sapwood can be treated against infestation by a recognised preservative

Note: Plywood complying with Australian Standards AS/NZS 2269 – Structural Plywood or AS/NZS 2271 – Exterior Plywood automatically meet all the above criteria

Purchase of Plywood

Product was purchased in the open market in Northern New South Wales by an EWPAA representative The EWPAA representative specifically requested a plywood product for use as underlayment for a strip floor The product was represented by the merchant as “the stuff everyone uses for underlayment” Refer Plates 1a and 1b

One sheet of the 15mm imported product was purchased and forwarded to the EWPAA National Testing Laboratory for testing and analysis

It should be noted that the sheet purchased did not have any labelling to identify the grade, bond type, formaldehyde emission class, the manufacturer or country of origin

The results of tests are as follows:

TESTS TO DETERMINE “FITNESS FOR USE”

1 Bond Quality and Thickness

Test specimens were extracted from the sample sheet and subjected to the four standard bond durability tests defined in AS 2754.1 Adhesives for Plywood

These bond types and their suitable uses are defined in Table One of AS 2754.1 which has been reproduced below

TABLE 1 – Extract from AS 2754.1 BOND TYPE CLASSIFICATION

Water soak treatment (prior to testing to Clause 7.2 of AS 2098.2) Bond

Type

Service condition Adhesive type

(see Note 2) Temperature Time

A Type A bonded plywood panels can be used in applications involving

extreme long-term exposure to weather or wet or damp conditions

and/or long-term structural performance requirements without

glueline breakdown or glueline creep

Examples: Structural plywood flooring, highway signs and marine

plywood

Synthetic phenol-formaldehyde, natural polyphenol-formaldehyde or mixtures thereof

100 C 72 + 1 h

– 0 or

6 h at 200 kPa steam pressure

B Type B bonded plywood panels can be used in applications involving

extreme short-term (not more than two years) exposure to weather or

wet or damp conditions and/or short-term structural performance

without glueline breakdown or glueline creep They can also be used in

applications involving long-term exposure to protected exterior

non-structural environments

Examples: Concrete formwork, exterior door skins

Melamine-urea-formaldehyde

100 C 6 h + 5

– 0 min

C Type C bonded interior plywood panels can be used in non-structural

applications involving full protection from the weather or wet or damp

conditions They can be used in applications involving long-term

exposure to generally high humidity and short-term exposure to

extremely high humidity

Examples: Interior panelling in geographical locations which have

prolonged periods of high humidity Panelling in a bathroom

Urea-formaldehyde

70 ± 1 C 3 h + 5

– 0 min

D Type D bonded plywood panels can be used in non-structural interior

applications fully protected from the weather or wet or damp

conditions They can be used in interior applications involving

long-term exposure to medium humidity with occasional exposure to high

humidity

Examples: Furniture, interior wall panelling

Extended urea-formaldehyde

15 C to

20 C

16 h to 24 h

NOTES:

1 Experience has shown that Type A bonded plywood will withstand complete exposure to the weather for 20 years or maintain its integrity in structural situations for 50 years without glueline breakdown or glueline creep

2 With adhesives or other chemical types, compliance with the test requirements alone would not indicate equal durability, and confirmation by actual service trials would be required

The results for bond quality tests are detailed in Appendix A

These results show that the plywood sheet tested has failed to meet either Type A, B or C bonding requirements and has only meet requirements for Type D

As defined in Table One of AS 2754.1, Type D bonded plywood is not suitable for use in applications where the plywood is subjected to wet or damp conditions or high humidity

Wet and damp conditions are at times typical for flooring underlayment which is frequently subjected to wetting when floors are mopped and cleaned The concrete floor itself can also be a significant source

of moisture when timber flooring is laid over new or green concrete In such conditions the Type D bond adhesive will rapidly breakdown and lead to failure of the floor

As stated previously, in applications where plywood is subject to intermittent wetting over a long period

a Type A or Type B bond glueline is required There is no doubt that the imported plywood tested will not provide an extended service life and the floor will fail prematurely The imported plywood is not suitable to provide long—term performance and durability

Thickness results are also detailed in Appendix A Results of these tests showed thickness to be uniform and variation from nominal (15mm) thickness is only slight In regard to the panel tested, thickness results are very good

2 Formaldehyde Emissions

The test results for formaldehyde emissions are detailed in Appendix B These are very disturbing as firstly, emissions were extremely high (4.8mg/2) and of more concern the emission class was not labelled on the panel identifying it as a high emission product

Formaldehyde has recently been reclassified as a known carcinogenic substance and as a result Australian plywood standards were updated to require labelling of formaldehyde emissions Every plywood sheet complying with Australian Standards must be labelled with the formaldehyde emission class However, as no claims have been made by the importer or supplier of the plywood tested of compliance with Australian Standards, this product has fallen outside of the labelling requirements of the Australian Standard

This in itself is a serious issue as failure to identify this product as a high emitter will lead to this product being used in applications where ventilation is poor and the floor area sufficiently large to cause formaldehyde to accumulate in the atmosphere to a potentially dangerous level

The use of this product without any form of labelling is extremely concerning It is the writer’s opinion, this product is not “fit for use” and potentially unsafe in unventilated or poorly ventilated applications or where sensitive individuals may be exposed

The EWPAA laboratory tests formaldehyde emissions from all certified products manufactured in the Australasia region

PLATE 1a – Face of purchased plywood sheet

PLATE 1b – Edge of purchased plywood sheet

By way of comparison all EWPAA certified structural plywood and Type A bond exterior plywood have an emission class of E0 with amaximum emission of 0.50mg/L In fact, the average formaldehyde emission for all structural and Type A exterior plywood products produced by EWPAA certified mills is only 0.26mg/L or half the permitted level and approximate to the natural formaldehyde emission from timber

The measured emission from the imported underlayment plywood was 4.8mg/L or approximately 18 times the average emission from EWPAA Certified Structural Plywood

3 Lyctid Susceptibility

Lyctid borers attack the sapwood of many hardwood species completely destroying the wood structure See Plates 2a and 2b Softwood species such as radiata pine and hoop pine are immune to attack Due

to the high risk associated with lyctid attack, it is illegal to market timber products in Queensland and New South Wales that contain unidentified untreated sapwood of susceptible species

PLATE 2a – Typical example of damage caused by Lyctid borer

PLATE 2b – Typical example of damage caused by Lyctid borer

The first sign of Lyctid attack is usually the presence of flight or exit holes in the timber product (See Plate 3) In the case of strip timber flooring, Lyctid borers commonly chew through the overlaying strip floor to escape from infested underlayment when mature to reach to the outside environment

PLATE 3 – Typical damage of flooring due to Flight Holes

The wood species used in the manufacture of the imported underlayment plywood have been identified

by the Queensland Department of Primary Industries and Fisheries (DPI&F) See Appendix C (Sheet 4 in the DPI report) DPI & F have identified have identified the core veneer species as “Populus spp.” Poplar

is a low density hardwood frequently used by Chinese plywood manufacturers Poplar is identified in AS

5604 – Timber Natural Durability Ratings as Lyctid susceptible This requires all sapwood to be chemically treated to prevent infestations by Lyctid borers In addition to species identification, the DPI

& F have also performed chemical analysis for the presence of approved insecticides used to treat against attack by Lyctid borers

In addition to tests performed by DPI & F, the EWPAA subjected the plywood to the standard test for the presence of sapwood defined in Appendix A of AS 1604.1 – Specification for Preservative Timber This test confirmed the presence of sapwood at a number of locations in the sheet

The results of tests for Lyctid susceptibility have shown that the species of timber (Poplar) used in the core veneers is a species susceptible and the presence of sapwood has been confirmed Chemical analysis by DPI & F have confirmed that the product has not been chemically treated to prevent Lytcid attack

These tests have confirmed that the plywood sheet is susceptible to attack by Lyctid borers

The sale of the plywood which the EWPAA has tested is actually illegal in the State from which it was purchased as it does not comply with the New South Wales Timber Marketing Act

The use of untreated Lyctid susceptible plywood underlayment is absurd as the risks associated with Lyctid attack far outweigh the cost benefit $2-3m2 in using a low cost imported substitute underlayment material Lyctid susceptible underlayment is quite simply not fit for use and it is highly irresponsible of the material supplier and flooring contractor to use such material

CONCLUSION

TABLE TWO- SUMMARY OF TEST RESULTS Product Property Requirement to be “Fit for Use” Result of Test Conclusion

Thickness Uniform thickness with only small

variation

Formaldehyde

emission

Low to medium and branded Very high and not branded UNFIT FOR USE

Lyctid Susceptibility Not susceptible or treated Untreated susceptible sapwood

is present

UNFIT FOR USE

This is a very worrying result with the panel tested failing 3 out of 4 performance requirements to ensure fitness for use as strip flooring underlayment

Testing by the EWPAA and DPI & F has confirmed the marketplace feedback received by the EWPAA of the significant increase in quality issues and premature failure of high value strip floors and flooring systems due to the substitution of imported underlayment plywood It is essential that building designers, specifiers, flooring layers and home owners are urgently made aware of the significant risks associated with the use of this low cost substitute product

To ensure that underlayment plywood is “fit for use”

1 Request product manufactured in accordance with Australian Standards Plywood manufactured in accordance with AS/NZS 2269 – Structural Plywood or AS/NZS 2271 Exterior Plywood are entirely fit for use These product standards require that the plywood has the following properties:

1 Manufactured using Type A or Type B adhesives

2 Thickness is controlled within tight limitations

3 Formaldehyde emissions are labelled allowing the consumer to readily identify and select low emission products

4 The use of Lyctid susceptible timber is prohibited

2 Independent Third Party Product Certification Request underlayment plywood manufactured under a JAS-ANZ accredited product certification scheme This ensures that manufacturers claims

of compliance to product standards are independently verified Suitable products manufactured under the EWPAA’s JAS-ANZ’s accredited certification scheme will carry the following certification marks

Structural Plywood Certification Mark

Exterior - Type A Bond Certification Mark

Exterior – Type B Bond Certification Mark

SIMON DORRIES

FEBRUARY 14, 2008