Home sweet home (capital gain tax) (Issue number 3)

Continue on the same topic on main residence (see issue 1 and issue 2), do you know that you can have two homes that could be regarded as your main residence and still entitled to the main residence exemption, during a specified period, if certain conditions are satisfied.
 
If you acquire a new home before you dispose of your existing house, both dwellings may be treated as the your main residence for up to six months only if the following conditions are satisfied:

• The existing main residence was your main residence for a continuous period of at least three months in the 12 months before your ownership interest in it ends (e.g. ending when the existing main residence is disposed of) ;
• You did not use it to produce assessable income in any part of that 12 months when it was not your main residence. For example, the condition would not be satisfied if during the 12-month period you did not live in the house and rent it out during that period ; 
• The new dwelling becomes your main residence

​
The exemption for both dwellings only applies for the shorter of six months (ending when the ownership interest in the existing main residence ends) or the period between the acquisition of the new dwelling and the disposal of the old dwelling.
 
Source: 
Moving into a dwelling          
Treating a dwelling as your main residence after you move out
Selling your home