Before asking builders/contractors for a quote, you must have the structural engineering plans complete. The structural engineer has a critical role to play in the build as they will specify what’s needed to accomplish your proposed plans. That includes the beam structure, number of beams, size of beams, foundation depth, etc.
A contractor will be unable to provide an accurate quote without knowing what work the project actually entails.
At the start of the project, I didn’t think I’ll be contacting the engineer much. I was wrong. I’ve contacted the engineer several times to confirm specs of beams and for the bay window structure. I initiate the meeting leaving the builders and engineer to discuss the technical aspect.
Back to the box topic. Our rear extension needs a lot of structural support as were breaking two of the outside wall and one side of the house could collapse if not done properly. To accomplish this, the builders had made a box frame out of steel beams.
Check out the images. You can see what the steel has to support and understand why it’s needed.