Structual Timbers Radiata pine and Oregon
Radiata
In New Zealand and Australia the species is grown in renewable plantation forests. Through selective breeding over many generations in New Zealand and Australia the Radiata pine tree now has significantly superior characteristics to those of the Monterey Pine and also to those of Radiata pine grown in other countries.
In New Zealand, the timber is graded into categories/grades that are applicable to specific end uses, the broad categories being Structural, Appearance, Remanufacturing and Industrial. There are a number of separate grades within each of these categories.
Most sizes and grades are readily available, with the most popular specifications nearly always in stock.
Radiata Pine Grading:
In the past couple of years, the softwood industry has introduced a range of new Machine-Graded Pine (MGP) grades that are specific to their timber. These stress grades are the result of new trends in the testing, evaluation, quality control, and grading of timber to give a more accurate assessment of the properties of a particular timber.
MGP grades apply only to softwood, but allow the timber to be substituted for F-graded timber where the MGP-grade properties exceed those of the particular F-grade specified. Builders are not allowed to substitute F-grades for MGP grades.
Australian and New Zealand plantation pine, for structural purposes, is available as seasoned grades of F5, F7, F8, F11, and F14, as well as MGP10, MGP12, and MGP15. Remember that in each case, the higher number of the F-grade or MGP grade, then the stronger the timber.
Applications and Uses:
Radiata pine is possibly the most versatile timber in the world. Subject to correct grade selection, appropriate preservative treatment and drying, the timber will perform extremely well in every end use application in which timber is typically used. Very popular for use in areas where a stained or painted finish is required. Modern technology can now produce any profile in finger-jointed radiata up to 6 metres long. Ideal for picture frame moulding as well as skirting and architraves.
|
OREGON
Oregon (pseudotsuga spp.) or Douglas fir, is native to eastern America, from Mexico to British Columbia. There, it is one of the most important commercial softwoods. The species originated in North America, however, it was introduced into New Zealand in the 1800's.
In New Zealand, the species is grown throughout the country, with the major forests being located in the central North Island, Nelson, and Tapanui areas. Mature virgin forest Oregon is classed as durable; however, the plantation product, if exposed to the weather, must be adequately waterproofed and maintained.
The easy workability and high strength-to-weight ratio of Douglas fir complement its structural strength to provide builders with an ideal general purpose wood for all phases of residential or light commercial timber frame construction. Douglas fir is stable in use, holds nails and screws securely, readily accepts glues, and is boldly attractive when left exposed to view in applications such as post and beam construction.
The hardness, texture and attractive colouration of Douglas fir rival those of many hardwoods commonly used in the manufacture of windows, doors, roller blinds, mouldings, ceilings, furniture and interior trim. The wood is easy to dry, particularly in clear grades and exhibits little tendency to check, warp, cup, twist, or split.
Applications and Uses:
Green Douglas Fir is used for the manufacture of residential roof trusses, wall frame, exposed beams and rafters. Kiln dried Douglas Fir can be used for interior panelling and joinery.
