TIMBER.

12/12/2013

Advantages of timber as a building material

• Adequate ultimate strength for most practical purposes 

• High strength/ weight ratio 

• Sufficient durability.

• Easily transported (particularly in small pieces).

• Possibility of reuse.

• Good thermal properties.

   

  Some disadvantages of timber as building materials.

  (i) Timber is a natural product with growth defects such as
  - knots
  - cracks
  - heavy resin pockets
  - twisted (spiral) fibres
  - reaction wood
  
  (ii) Conversion timber
  - mistakes due to unsound practice (milling techniques)
  - attempt to use every possible piece of timber (financial gain)

  
  (iii) Wrong seasoning practice
  - poor stacking and space arrangement of the freshly sawn
  timber i.e. splits, cupping, bowing or twisting

  
  (iv) Timber is an organic material therefore is has
  - low resistance to fire
  - vulnerable to fungi and insect attack
  Solution to fungi and insect attack is special treatment which can
  be costly.

  
  (v) Anisotropic behaviour
  - strength varies with respect to direction of loading 

   

  Grain Orientation in a timber structure. 
  
  

  (vi) Hygroscopic behaviour
  - properties of timber are sensitive to moisture content

   

  Advantages of timber construction.

  Timber possesses the following distinct advantages in preference to
  other engineering materials:-

   
  (i) It can be easily handled and can be planed, sawn and joined with ordinary tools of the carpenter.

   
  (ii) It can be used either for load bearing members or for non-load bearing members.

   
  (iii) It combines light weight strength and then it is generally preferred for the building materials in the earthquake pronen regions.

   
  (iv) It is easy to provide connections in the timber construction.

   
  (v) It is economical and cheap. This is due to the fact that the smallest piece of wood can be put to one or other use and wastage of material is thereby considerably minimized.

   
  (vi) It is possible to realize some value even after timber construction has completed its useful life i.e. it can be reused.

   
  (vii) It is used to prepare furniture of decent appearance and comfortable design.

   
  (viii) The houses with timber construction are found to be cool in summer and warm in winter. This is due to the fact that wood
  is non-conductor of heat.

   
  (ix) The other form of present day such as plywood, fibreboards etc. have made timber construction to match with present day requirements.

   
  (x) The timber construction is quite durable if properly protected against moisture, rain, wind etc.

   
  (xi) The additions, alterations and repairs to the timber construction can be carried out easily.

   
  (xii) It is found to be superior to the cement concrete and steel in respect to thermal insulation, sound absorption and electrical resistance.

   
  (xiii) It is easily available and be speedily transported by simple means of communication.

  
  

  Disadvantages of timber construction.

   
  (i) It is likely to crack, warp or decay, if not properly seasoned and not treated with preservatives.

   
  (ii) It is not suitable for cyclonic weather and for places subject to the natural calamities.

   
  (iii) It requires careful regular maintenance.

   
  (iv) It is subject to the risk of fire.

   
  (v) If not locally available it proves to be costly.