IQT f2w
Wood materials and items used in building practice include round timber (log); sawn timber
and planks; floor materials—flooring boards, end-grain blocks and fibre board; carpentry
items— doors, windows, partitions, panels and gates; roof materials—shavings, tiles and
shingles, members of roof trusses; wooden structures—beams, columns, slabs, and items of
prefabricated houses.
Glued wood components—e.g., beams, trusses, arches, frames and roofs of buildings and
installations— are very effective in chemically aggressive media because their service life is 1.5
times greater than that of steel or reinforced concrete. However, the use fo wood should be
economically justified and the possibility of replacing it with prefabricated concrete, asbestos-
cement, gypsum, plastics and other items should be carefully considered.
The use of fibreboard, ply-boards in building practice provides a substantial saving both in
capital investments and running costs. The economy is provided, in the first place, by a more
complete utilization of raw materials for the manufacture of building materials and items.
The use of boards made of pressed wood shavings in dwelling house construction has a
great economical effect. Currently, wood waste is utilized to manufactures polymer and cement
based fibreboard and wood shavings board. This also allows manufacturing materials of better
physical, mechanical and decorative properties than wood.
iigsi
- Draw the cross-section of a matured tree. What is the best season for felling a tree?
- What suggestions do you propose for improvement in construction to avoid decay of
timber, and what measures are to be taken, when it has occurred? - (a) State the principal causes of decay of timber.
(b) How is seasoning done on a large scale?
(c) Discuss the methods of preserving timbers. - (a) What are dry and wet rots? How are they caused and prevented?
(b) What is seasoning of timbers and why is it done?
(c) State the qualities you will consider in selecting timber for construction purposes? - (a) What is the effect of paint on unseasoned timber?
(b) What are the requirements of good preservatives? What are the main types?
(c) Describe various defects in timber? - Explain the following defects of timber.
(a) Shakes (b) Rindgall
(c) Upsets (d) Knots - (a) What is the difference between soft wood and hard wood?
(b) State the characteristics of good timber.
(c) Describe briefly the methods of timber preservation.
(d) What are the diseases of timbers? - Write short notes on the following:
(a) Defects in timber (b) Ply wood
(c) Seasoning of timber (e) Hard board
(d) Preservation of timber (f) Veneers