I built my two storey extension for 20% of builder's quotes

This site shows how - step by step from design to completion

Structural Design Calculations for my House Extension

Some strucural calculations would be required to add to my building regulations control drawings. Do I need a structural engineer for my extension? Well technically, no, so why do I need a structural engineer? Though I was planning to do all the design and build myself on this project, I do happen to know a friendly freelance structural engineer that drinks in our pub, so decided it was speedier and easier just to ask him to do the calculations for the RSJ's. If I didn't just happen to know someone then I would likely have done the calculations myself. I had searched the internet and found structural calculations for dummies and some structural engineeer calculations online. As I planned to buy roof trusses rather than make a cut roof, the calculations for the roof would be done by the truss company. I don't think that doing the structural calculations building regulations would have been that difficult when just considering the RSJ's.

I had run my rough plans past a local structural engineer at an early design stage. Now I had planning permission it was time to call him back, formalise arrangements and talk though the calculations I needed for my BCO plans.

I planned to take out a load bearing wall and have a couple of support steels in my new build. To add further complications, I also had a well in my kitchen that would need capping off. We talked through all the calcs I needed. He then went away to draw up my structural plans.

Though I planned to do all the new build work myself, I really didn't fancy taking responsibility for removing a load bearing wall so I called in a local builder who has worked with my structural guy before, to talk through the wall removal and get a quote.