Make sure the company answers all of your questions to give you enough information to make an educated buying decision. Check with your local Better Business Bureau to see if there are any complaints on file – and whether those complaints were resolved.
If the contractor has a showroom, check out their workmanship and the quality of their materials. The company should provide you with accurate to-the-penny pricing, without any hidden costs. Be careful about estimates or bids – they are often unreliable and you may find yourself paying more for the project than you were led to believe.
The company should use their own crews to install the room. The contractor/foreman should supervise the project with regular on site visits. The company should have a process to immediately notify you of changes or delays in the schedule. The company should take care of obtaining the building permit and arrange for the final inspection. Make sure that the company does in fact pull a permit; this is their responsibility. Without a valid permit and certificate of occupancy, you might not be able to sell your home with the sunroom in place.
The company should provide you with a complete and thorough walk through inspection of the finished product. Make sure the company or contractor warrants their materials for several years and wants you to be totally satisfied with your sunroom.