build plans

Hi I have recently moved into a 1930s bungalow which had a single storey with extension added in the 1970s. At first I noticed a crack that runs along the join of the extension to the main house at one corner which is both external and internal. Also recently though I've noticed the floor bumps...

I have a small workshop from a pent shed, it's all wired up to the consumer unit and certified. However it is really to small and two low to work in. I want to build a bigger workshop around 4m x 4m. I will keep it pent and frame will be 6 x 2 C16/C24 timber. The issue I'm having is I can not...