Re-wiring of a semi detached house

Get an EICR ( Electrical Installation Condition Report ) done on your property. By a reputable electrician.

The most common reason for needing a rewire is that the electrical insulation between the conductors in your properties cables is breaking down. This is measured by an electrician whenever they modify any circuit. An isolated 'low' insulation resistance might be due to some other problem which can be rectified but if it occurs on multiple circuits its most likely the cables themselves.