Who is responsible for repairing my commercial business premises?

If you have a lease of the whole building, there is likely to be full repair liability which means the tenant is responsible for all repairs including structural parts such as the roof and foundations.

If the lease only covers part of a building, for example one floor, then your responsibility will most probably be limited to the interior shell. The landlord would be responsible for the structural parts of the building however, a tenant can still be liable for the external parts or be required to contribute towards a fair proportion of the total cost incurred in repairing and maintaining the building by way of a service charge. The shorter the lease the less responsibility you should accept. Tenants should seriously consider obtaining a schedule of condition to limit the level of repair.