February 2024

exceptional properties. However, even if it was
clear to us that Roofshield was not to blame, we
still needed to figure out why the water leak
incidents occurred in the first place. There must
have been some reason.
Through ongoing testing, it has been established
that leaks in membranes are frequently tied to
the presence of timber treatments on certain
battens commonly used in roofing applications.
Notably, specific chemical components within
timber treatments potentially impact all synthetic
membranes. This testing, stemming from Don &
Low’s technical expertise, reveals a significant
concern affecting the entire roofing industry.
But why now? What’s changed between
2022 and 2023?
Several factors have contributed to the increased
incidence of treated timber causing this effect.
The change in the supply chain for roofing
battens, affected by COVID-19 disruptions and
geopolitical events like the Ukraine-Russia war,
has led to an emergence of non-traditional batten
manufacturers, and these are coupled with
different treatment processes and exceptional
rainfall. During 2023, the UK timber market has
been grappling with quality issues and incorrect
grading to BS 5534.
“Contractors should
adhere to the
installation guidelines
and best practices”
Don & Low’s ongoing testing into issues of leaks
has established a link between the presence of
certain chemical components within timber
treatments leaching from saturated battens,
affecting the performance of membranes. A
common factor found throughout the majority of
investigated installations was the presence of
contamination on/in the membranes that
compromised the water holdout performance.
So, it is evident that we are not discussing
a Roofshield issue.
Absolutely. We recently commissioned the BRE, the
UK’s renowned science-led construction research
facility, to subject Roofshield® to extreme weather
testing. The testing, designed for primary roof
coverings, was carried out with dry battens known
not to contain chemicals that compromise water
holdout, and a variety of pitch angles were used to
assess the effect on low and high pitch roofs. The
results were conclusive: Roofshield® showed zero
leaks, exceeding the required standards for airpermeable
roofing underlays.
Designed and manufactured in the UK,
Roofshield® has been tried, tested, and trusted
by the industry since 1996, and is certified by the
BBA. All Don & Low products undergo rigorous
testing, and these findings underscore that
Roofshield remains reliable. Don & Low, as
industry leaders in vertical manufacturing of
construction membranes, stand behind its
integrity.
What suggestions do you have for
contractors in consideration of your
ongoing investigation?
Contractors should adhere to the installation
guidelines and best practices. Battens should be
dry to prevent chemicals from leaching onto the
membrane, and battens should not be treated in
situ. We have observed the growing reports of
skin issues by roofing contractors online and
would advise wearing the correct PPE. Further
enquiries can be directed to our construction
hotline at 0808 169 4444, where our team of
experts is always ready to assist.
Contact Don & Low
www.donlow.co.uk
Don & Low Ltd.
FEBRUARY 2024 TC 25