Dear ViatronMac
I checked your matter with a close personal friend - the Chairman and MD of one of the biggest construction firms in Sri Lanka.His opinion is forwarded below:
R. 230 per sq.ft. complete roof is very reasonable. Going rate with entire timber frame, valley gutters, hip tiles etc., Mangalore roof tile going rate is close to Rs.300/- per sq.ft.
Rs.250,000/- per man week for skilled labour is very high. It should be around Rs.100,000/-. Without knowing the exact scope, it is difficult to give any definite response to your query.
Timber must be treated and backed by a Certificate of Treatment or impregnation.
Import timber are of various specimen and some get attacked within 3-5 years.
Are the beams exposed. Then only you need to machine sand all round. Otherwise only one side is needed.
I trust this helps.
Kind Regards
Alan David