A
quick guide for the specification of preserved timber. To get your
specification right you must take into account the following: Use Class,
Timber Species and Service Life.
Interactive
Diagram - Please click the appropriate letter for more information
4. Direct Soil or Fresh Water Contact
5. Marine Situations
Component
Use
Class
Recommended
Treatment
A
Domestic
pitched roofs, all structural timber
1
B
Condensation
- risk pitched roofs - all structural timber
2
C
Tiling/slating
battens
2
D
Flat
roof timbers
2
E
Barge
boards, fascia boards
3
F
External
frame - outer leaf
3
G
External
frame - inner leaf - except sole plates
2
H
Frame
sheathing - plywoods *
2
I
External
cladding
3
J
Battens
for fixing external cladding
2
K
First
floor joists
1
L
External
joinery
3
M
Surrounds
for non-wood windows
3
N
External
doors
3
O
External
door frames
3
P
Ground
floor joists
2
Q
Sole
plates above DPC
2
R
Sole
plates below DPC
4
S
Decking
3/4
T
Fencing
posts
4
U
Marine
structural timbers
5
V
Swimming
pool surrounds (external)
4
In these circumstances these treatments are acceptable but not recommended
H* Certain grades of plywood can be preserved with
please check.
Osmose Naturewood
Applies to timber
that has been preserved with Osmose copper based preservatives such as
the Celcure AC range, for external applications both in-ground contact
and out-of-ground contact e.g. timber decking, fencing, landscaping timbers
and other outdoor timber projects. Alkaline Copper Quaternary systems
have provided proven performance for a decade in locations throughout
Europe, North America, Australia and Japan.
PROTIM ClearChoice
Applies to timber
that has been preserved with PROTIM Aqeos or Drysol for use in internal
construction and joinery projects (eg timber-frame trussed rafters and
doors and windows). The timber is also suited for external out of ground
contact applications when used in conjunction with a coating.
A Quick Guide ...
By providing your specialist
preserver with the appropriate information they will ensure your timber is preserved
to the proper specification. The expected service life of timber varies according
to the species and hazard classes. Please check with your preserver. Particular
specifications such as British and European standards, the Highways Agency the
Australian Quarantine Inspection Services and NHBC can be complied with provided
that the appropriate preservative and treatment cycle is used.
Suggested Standard Specification
Clause
Architects can refer to
their NBS standard clauses. A useful phrase could be as follows
"Preserve
timber to hazard class ….. using a suitable preservative for that use
class. Preserve any cut ends with appropriate cut end preservative."
you may specify the timber
type and the preservative yourself.
More comprehensive information
is available from our Technical Services section concerning hazard classes,
timber species and service life. We will be happy to direct you to your nearest
preserver. The above is intended as a quick guide only. Please check for specialist
applications. Always check for your particular end use if in any doubt.
OSMOSE
Protim Osmose Ltd
Unit 8 Abbey House
Main Street
Clonee
Co. Meath
Ireland
Ph. 00 353 1 8251084
Fax 00 353 1 8251085
