Defects of timber

This survey is often called a timber cruise and involves a series of measurements of individual trees, as well as an assessment of factors that will influence the price of your timber. These are cracks that develop parallel to the annual rings.

A cunit is simply cubic feet of solid wood. Wane is not desirable in structural timber although it may be tolerated in some situations, such as when members are larger than necessary to perform their structural function. Timber remains one of the most useful in a world of diminishing resources and is a major component in most historic buildings.

All boards should have an allowance so that some end grain may be cut away because of possible shakes or splits. The measurement of standing timber and logs may seem strange and complicated to you, and it is possible that you may be quoted dramatically different prices based upon differing estimates of the amount of timber you have and the units of measurement used.

It is their larvae which cause most damage as they bore through the wood, feeding off it and causing damage to the structure and strength of the timber. It is seen only in saw-on timber, on one edge of the cut portion.

Useable timber may be recovered from these boards by cutting a straight edge and re sawing. The timber strength is reduced, but in some cases will retain sufficient residual strength to perform its function possibly with some level of strengthening.

Beetles responsible for the decay of timber principally include woodworm Anobium punctatumdeath watch beetle Xestobium rufovillosumpowder post beetle Lyctus sppand house longhorn beetle Hylotrapes bajulus.

Timber Veneer

A solid cord, therefore, contains cubic feet; however, wood is not bought and sold in terms of solid cords. The presence in any surface of local discontinuity of grain or local deviations in the straightness of grain because of knots permitted in the piece shall be disregarded in applying the provisions of this chapter.

Identifying Hardwood Defects Part One

Use Class 4 Timbers destined for Use Class 4 situations will be permanently exposed to wetting in either groundor fresh water contact. Buyers of timber will always need to conduct a survey of your woods before they can make an offer.

There are two main types of wood-rotting fungi found in buildings; wet rot and dry rot see Table 2. Some of the above types are defined as follows: They generally arise in the sap wood and extend towards the inner regions. These are cracks or clefts occurring in the heartwood, i.

A knot on the surface of the log or a branch on a tree always represents a knot in the underlying wood. The shake is the result of stress relief and in the first place results in a single longitudal crack from the heart and through the diameter of the tree.

Langhorn Beetles Cerambycidae Attack by these insects, of which there are many species in tropical and temperate countries, results in the presence of dust filled tunnels, varying in size, in newly felled logs and sometimes in standing trees. A Pennsylvania homeowner alleges to have been trying, unsuccessfully, for six years, using the TimberSIL warranty claim process, over a deck installed in that is now allegedly rotting.

After knots, shakes are more serious and common defects in timber. Some timbers, typically many hardwoods, are naturally durable and resistant to decay.

Further cracks are known as star shakes and show the familiar pattern shown. Shrinkage on aging of the tree; due to movement caused by wind action in the growing tree; freezing of sap in the cells during its ascent. Boards with this defect may have been cut from near the heart of the board and is the result of growth stresses being released on conversion.

Dry rot is notable for its ability to spread through walls and across inert surfaces to spread widely throughout a building. Watch the Video Below for Better Understanding. They are also called radial shakes.

Additives are available that can give either a rich brown colouration, usually for rough sawn fencing and landscaping timbers, or an effective extra water repellency protection for decorative external timbers, such as decking and cladding timbers. By reducing the need to expose and cut out infected material, environmental control also reduces damage to the fabric and the finishes of a building.

Termites Termites or White Ants Order Isoptera Information on the resistance of hardwoods to attack by termites in tropical and sub tropical countries is incomplete and data often conflicting.

This reduces the durability of the timber. (a) Defects in timber which has not been converted Shakes: Shakes are defects in logs, which have not been converted, or in large timbers.

There are a number. Correct Identification of damp problems and building defects is essential if the right treatment is to be given.

Incorrect diagnosis and leaving defects can lead. This presentation lists a number of defects, their characteristics and cause, and whether or not their effect can be offset by adjustments in scaling. Having a solid grasp on hardwood defects is essential when appraising, selling or purchasing timber and logs.

Timber can have various blemishes or defects, including shake, checking, wane, and splits. Most are accounted for in normal engineering reviews, but sometimes if the defect is large, it can cause a structural problem.

Lumber Characteristics & Defects One of the most obvious lumber characteristics. A knot is a portion of a branch or a limb that has become incorporated in a piece of lumber. The knots described in our lumber are generally sound knots, unsound knots and knot holes.

Some hardwood defects are on the surface and are more easily observed; others are interior and become apparent once timber is cut down and the surface on the log end is observed. This presentation lists a number of defects, their characteristics and cause, and whether or not their effect can be offset by adjustments in scaling.

Defects of timber
Rated 4/5 based on 32 review
Wood drying - Wikipedia