Can you confirm whether the cracks are a subsidence problem?

Cracks in walls, ceilings and floors are caused by several different reasons. Depending on the size, exact location and frequency of the cracks, the risks associated can vary substantially. Subsidence or movement of foundations can often cause cracking and structural damage to the building above. There are often a variety of causes for these movements and the investigation and remediation can vary based on the cause and associated risk.

When can I start work?

You can start work once you have the complete design package, necessary agreements such as; planning permission, party wall agreement (if applicable), free holder consent (if applicable), finance, building control or NHBC if required in advance and of course once you selected a suitable reputable building contractor you are happy with.

Can you reduce steel size and weight?

This will depend on many design factors and parameters and there is definitely no one set answer. For example a solution to reduce beam weight might be done by choosing two lighter beams instead of one beam or by changing architectural layout and inserting a column somewhere along the span of the beam or by changing the structural layout of the beams, etc. The options can be endless so best to discuss specific requirement with the project engineer with open mind that each project is different and solutions can vary from project to another.

What is party wall agreement and do I need one?

Your works may fall under the regulations of the Party Wall Act 1996 if you are building a wall up to or astride the boundary with a neighbouring property, undertaking work to an existing wall or excavating near a neighbouring building. It is recommended to speak to a party wall surveyor if you are in doubt.