TDUK SupplyingTimber Issue 8 DIGITAL - Magazine - Page 57
———— TIMBER DECKING ————
E IMPORTANCE OF USE CLASS 4
The role of DeckMark
accreditation
DeckMark accreditation plays
a crucial role, assuring buyers
that the supplier adheres to
industry standards, giving them
con昀椀dence to buy from you.
It also serves as proof that
an accredited company o昀昀ers
quality materials and reliable
service.
DeckMark is an independent
third-party veri昀椀cation scheme
operated by the TDCA, with
an annual audit as part of
its qualifying criteria. The
objectives of the scheme are:
• To provide independent
assurance that products
supplied for decks and
associated outdoor wood
structures are 昀椀t for purpose
and accurately described.
• To provide installers with
evidence of the use of
good practice construction
techniques in accordance
with TDCA guidelines and
relevant British/European
standards.
• To help speci昀椀ers, regulators,
buyers and inspection
authorities identify quality
assured products, suppliers
and/or contractors
through accreditation and
certi昀椀cation logos.
The TDCA welcomes new
members to the DeckMark
scheme. If your company takes
pride in maintaining
high standards and would like
to get involved, please contact
info@tdca.org.uk.
www.tdca.org.uk
SUPPLYING TIMBER
57
SPRING 2025
CHECKLIST FOR DECKING
SUBSTRUCTURE COMPONENTS
The Wood Protection Association o昀昀ers the
following guidance:
• Con昀椀rm the component is suitable for
outdoor use and has been impregnated
with a wood preservative in an industrial
treatment plant (preferably independently
accredited).
• Ask your supplier to verify the wood
meets Use Class 4 speci昀椀cation, perhaps
on the delivery note or with a treatment
certi昀椀cate, and keep the documents safe.
• Determine the claimed service life – it
should be comparable to or better than
the deck boards you have chosen.
• Never substitute wood treated for an
indoor application for use in an external
application – early failure is inevitable.
• When cross cutting, notching or boring
treated wood products, always apply
an end grain preservative treatment to
freshly exposed areas to maintain the
protection's integrity. Never put cut ends
in the ground, even if the end grain has
been coated.
USING TIMBER
USING
TIMBER
campaigns, we are determined
to turn the tide on this issue.”
This problem is exacerbated
by the fact that, once a deck is
completed, the substructure is
typically hidden from view. As
a result, the consequences of
poor speci昀椀cation or shortcuts
during installation do not
become apparent until it’s too
late.
The substructure provides
support for the deck boards
above and is critical to deck
safety: as composite deck
boards are often 昀椀tted over a
timber substructure, the same
applies.
