The duration of the conversion project depends on various factors; however, from my experience, most renovation jobs are finished in 6 to 9 months. Still, it is hard to ascertain just how long the construction process will last.
The construction of completely new multiple dwelling units can take longer than one year. Keep in mind that construction work is halted during wintertime because the weather conditions hinder concrete's drying process.
In the case of renovation, weather conditions are less relevant, because most of the work is done indoors. This significantly shortens the duration of the renovation process.
Once the construction/renovation project is finished, the next step is the legal separation of all the apartment units and the transfer of ownership.
Before the renovation process, the owner of the house claimed the official legal ownership of the sole dwelling. However, now, every apartment must be registered in the official Land Register or Cadaster Institution, and the new owners must be documented, as well.
There are cases when the act of legal separation is not possible, and this can be solved by agreeing to share mutual ownership of the property.
Instead of owning two apartments of six in total, you will officially own one third of the entire house.
Please note that the process of transferring property ownership varies from one country to another, or from one state to another, in the United States' case.
However, the procedure itself is straightforward and consists of several steps that I believe are similar in most legal systems in the world.
First of all, the owner needs to address his request to the Land Registry or the Land Records Department (in some countries, the institution is known as the Agency or Institute For Real Estate Cadaster).
Since we are living in the digital age, these institutions offer electronic services, so downloading and filling out the forms is relatively easy.
For instance, if the property you will be converting is located in the UK, you can follow this link and inform the owner of the house to choose the 'transfer of part of registered title' form, since he is only transferring part of his/her property.
The next step is filling out the individual certificate, since the house is in private ownership.
As soon as the owner fills out the form, based on the application of the property, he/she will need to pay a fee.
After the formal procedure is finished, the Land Registry will publish the following information online:
the name of the owner
the price paid for the property and
a plan of the property's boundaries.
The registration of the property gives you proof of ownership, protects your property from fraud, and makes it easier to change, sell or give your property away in the future.
In the US, the task of transferring ownership is more complex, and involves gathering all original documents pertaining to the house's ownership. If the property carried a mortgage that has been paid off, then the owner needs to include a copy of the release from the bank.
The two parties (the current property owner and the future owner) need to hire title agents, who will witness the signing of the deal and will also notarize the new property ownership deed.
As soon as the owner of the house agrees to transfer the apartments in your name and the developer's name in court, you claim sole ownership of your apartment.