JH Mayor: Timber and Fencing Specialists




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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.


USE CLASS (HC) OF TIMBER IN END USE

1. Internal Dry, Insect Risk
2. Internal, Risk of Wetting
3. External, Above Ground, Frequent Wetting

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 Timber Specification Guide - Click to download

 

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 use 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.

 


John Hy Mayor & Sons Ltd.

The Sawmills
Southport Road
Ulnes Walton
Leyland
PR26 8LN

Tel: 01257 451303
Fax: 01257 453736


Opening Hours

Monday to Thursday
8:00am till 5:30pm

Friday
8:00am till 5:00pm

Saturday
8:00am till 4:00pm

Sunday
10:00am till 4:00pm



WE ARE OPEN MOST BANK HOLIDAYS

© Copyright 2011 JH Mayor
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JH Mayor & Sons are timber and fencing specialist based in Leyland, near Preston.
We stock a wide range of products including Building Sand, Rockery Stone, Concrete Mix, Decking, Paving, Flag Stones, Fencing, Fireworks,
Gazebos, Summer Houses, Sheds, Log Cabins, Garden Furniture, Gates, Timber, Tools, and Walling