Manual Lifting
When considering the health and safety aspect of a job you should not neglect the manual handling.
Are there going to be any heavy materials such as roof trusses, concrete lintels etc. If so, decide on what actions you can take to avoid the risks of manual lifting such as using lighter materials, materials supplied in smaller bags, use of wheelbarrows, hoists etc.
When materials are delivered, try to get them unloaded as close to where they are required as possible. Plan your layout to make this easier.
Related article. Thermalite is doing its bit for health and safety by adding hand holes to its Trenchblock. These blocks are over 50% bigger than normal blocks yet still way less than 20Kilo. A review of the trenchblocks can be read here.