An
alternative to an individual designer is the package supplier
who offers project management services all the way upto offering
a full 'turnkey' service - i.e. you sign off the whole project
to the company that designs and executes the project. All
you have to do is to turn up to move in after the construction
period.
This
service, although is more expensive, will relieve you of the
nitty-gritty of construction. But, be sure to verify that
the Company is reputed and will be using quality materials
for construction. This can be assured by mentioning the specifications
of materials including sizes and brand names, in the contract
document.