It is important to select the correct timber type and grade for the intended application, in order to help in your choices we have detailed some information about timber types, grades and the terminology used in the industry.
GREEN / FRESH SAWN
Crocadon sources round logs from the previous Autumn's felling when the trees are dormant and the sap is low.
Green timber has a relatively high moisture content and is therefore prone to shrinkage and movement as the drying process takes place. Shrinkage is usually in the width and thickness but not in the length. Traditional buildings were often constructed of green Oak and proves it to be an excellent medium for new build constructions and outdoor projects.
Note: Stainless steel fixings should be used with green oak as the tannins in the timber when in contact with iron can cause black stains.
Air drying is a natural method of seasoning timber making use of wind and sun. Wind, by circulating the air, prevents it from becoming saturated with moisture from seasoning timber and the sun by raising the temperature of the air, lowers its relative humidity. The combined effect of these two factors is to maintain the drying power of the air. Moisture content of air dried timber varies appreciably at differenct seasons of the year. Moisture content ranges between 15-20%.
Air dried timber is particularly suitable for windows and external doors as well as many other general uses inside and out.
Kiln drying is effected in a closed environment with controlled air circulation, humidity and temperature. In consequence kiln drying acheives a lower moisture content than possible with air drying. It is the only way that timber can be conditioned for interior use requiring lower equilibrium moisture contents. The kilning process also sterilises the timber as the temperature and humidity maintained in a kiln are lethal to any insect or fungus present in the timber when placed in the kiln.
AIR DRIED / SEMI AIR DRIED STRUCTURAL BEAMS
Air dried oak takes approximately 25 mm per year depending on the environment in which it is stored. Our beams are generally stored between 6 months and 6 years. Supplied in a sawn finish which is the traditional look in period properties.
Furniture Grade timber is more decorative. It is selceted for its grain patterns and character features.
Joinery Grade timber is a clean grade suitable for joinery applications including windows and doors, where it is important to have stable timber.
Good quality Boatskin Larch, clear and knot free needs to be up to 100 years old and properly managed in its youth to meet boat building requirements.
A striking feature of most timber is the differentiation between sapwood and heartwood. Generally sapwood is lighter in colour and less durable than heartwood as sapwood is rich in plant food material that can be attractive to certain wood rotting fungi and insects. Heartwood posesses more natural resistance to fungal and insect attack.
As a tree increases in diameter it gradually envelops the bases of branchesl the portions of the branches enclosed within the wood of the trunk are called knots. Knots vary in size from a pin head to many millimetres in diameter, they also vary in shape. Knots have an important bearing on the utilisation of timber, for example knots can contribute to the decorative value of timber used in panelling or flooring.
Grain refers to the direction of the fibres in the tree.
Straight grain timber has fibres that are more or less parallel to the tree, giving strength and ease of milling but not contributing to ornamental figuring.
Wavy grain timber has fibres that constantly change direction, this type of grain is important in the decorative value and any reductions in strength are of no consequence, for example decorative furniture.
Figure refers to the pattern produced on longitudinal surfaces of wood, as a result of the arrangement of the different tissues and the nature of the grain.
Quarter sawn timber is wood cut parallel to the rays.
Skirting and architrave can be supplied in the following profiles:
Torus, Ogee, B.Ovolo, Bullnose, Chamfer, Square Edge
FS / Fresh Sawn: Fresh sawn featheredge boards offer an economical and attractive 'weather screen' type of cladding. Good for applications such as barns, sheds and fencing. Please allow a minimum of 25mm overlap when calculating square area required.
Air Dried: Air Dried cladding offers a more sleek and neat finish than the fresh sawn timber options. They are suitable for horizontal and vertical applications on domestic and commercial buildings. Available in shiplap, TG&V, V or square rebated & rainscreen.