Most candidates were able to explain the differences between wood single and clay tiles.

However, some candidates were unable to:

-           differentiate between tools and equipment used for establishing straight lines and levels on a building site;

-           state four desirable properties of coarse aggregates for concrete production.

The expected response to question 1 is as given below:

(1)       Ranging poles
                                    (2)       Chaining arrows
                                    (3)       Builders’ square
                                    (4)       Chains
                                    (5)       Line and pins

(ii)        Equipment for establishing levels

(1)       Levelling staff
(2)       Dumpy level
(3)       Cowley automatic level
(4)       Engineer’s precision level
(5)       Theodolite
 (b)     

(i)         Desirable properties of coarse aggregates for concrete production

(1)       The aggregates should be clean and free from impurities;

(2)       The crushing strength of the aggregates should be at least equal to that of the cement paste that binds the particles together;

(3)       It must be durable and not liable to any form of shrinkage, swelling or decomposition;

(4)       Organic impurities should not be present in the aggregate (it affects the setting and hardening);

(5)       Aggregates should be free from salt compound.

(ii)        Differences between fine and coarse aggregates as used in concrete production;

Fine aggregates are the particles that pass through a 5 m mesh sieve while coarse aggregates particles are retained on the 5 mm mesh sieve.