The long-term performance of pressure treated wood decks is being compromised by a failure to follow manufacturers installation instructions says the Timber Decking Association (TDA). According to the TDA, the need to re-seal cross cut ends, notches or borings made while installing treated wood is not being carried out in some sectors of the market. As a consequence, components are exposed unnecessarily to the risk of fungal decay resulting in a dramatically shortened service life. If a structural component is involved then the ongoing safe use of the deck becomes a major issue.
Steve Young, Director of the TDA says that market feedback indicates the practice is most widespread in the DIY and jobbing builder sectors where awareness of how to use pressure treated wood may not be as high as it is in the professional design and build sector.
Commenting on the poor
installation practice he said:
“There is a widely held perception that if wood is green
treated you can use it and abuse it in any situation.
This is a myth. Wood protection is a controlled
scientific process in which the treatment is tailored to
the type of wood, the end use and the service life
required. Like any other manufactured product, if
treated wood is not used and installed properly it will
not work as effectively as it should. Users who ignore
manufacturers instructions really are inviting problems
with all the time, trouble and expense involved in
putting them right.”
The TDA is keen to
remind deck builders that the only way a pressure
treated component will deliver the service life expected
is if the original treatment is not compromised:
“Sealing surfaces exposed by procedures like cross
cutting maintains the integrity of the treatment” says
Young who is also quick to point out that the practice
also preserves any long term performance warranty given
by a manufacturer: ”Quality pressure treated decking can
come with a guarantee of 15 years or more but this is
rendered invalid if end grain preserver is not used on
cut ends.”
Cans of end grain preservative (also known as cut ends
sealer) should be available for just a few pounds from
the same outlets that supply pressure treated wood. End
grain sealers that are accredited to the TDA’s DeckMark
product quality assurance scheme are available from wood
protection specialists like Arch, Osmose and ICI
Cuprinol. More detailed information about good design
and installation practice in general is available on the
TDA web site: www.tda.org.uk
The TDA is working with
other timber industry organisations like the Wood
Protection Association and Wood For Good to help raise
supply chain knowledge about specifying and installing
pressure treated wood for decks and landscape joinery
which includes access to a one-hour online training
programme.