Just contracted out main gates work to some local company (not to local welders) in Islamabad.
Rate of gate for the design selected is Rs.750 per sq ft.
From research came to know few points regarding sliding gates:
1) Channel that is grouted in the floor on which gate drags should be of suitably wider diameter. Local welders put thin angle iron as channel to save costs which makes it very hard to drag the gate.
2) Diameter of wheels must be proportionate to the size and weight of gate and must have double bearings in it for long life and smooth flow.
3) Louvre type designs in sliding gates are considerably cheaper (at around Rs.600 - Rs.650 per sq ft)and are long lasting as louvers are placed at angles water tend to flow out of them instead of getting stuck like in pipe wala design gate.
4) Proper weight distribution in gate design is mandatory for gate to flow smoothly on its channel.