When thinking about converting a terrace house possibly one of the most important things you need to think about is the Party Wall Act.
With neighbours on both sides then things are obviously different than if your property is an end of terrace or semi-detached.
That being said it doesn't mean that there is anything more problematical with a middle terrace conversion - just slightly more paperwork if anything.
The Party Wall Act
People usually assume that the Party Wall Act is all about protecting your neighbours. But actually it is more to do with establishing your rights to improve your home.
Your neighbours are protected in that you have to notify them of your intention to commence building work but they cannot stop you going ahead without good reason and the legislation also allows you to cut into or demolish and rebuild the party wall.
In the case of a mid terrace loft conversion you will of course be dealing with two separate neighbours but that does not necessarily mean more complications.
Other Things To Consider
Typically a mid terraced house is ideal for conversion. Those terraces built up to the mid 1960s will usually have large lofts with a a nice steep pitch.
After the mid 1960s and in order to save costs on materials builders began to build properties with shallow pitch roofs and built with a tangle of truss rafters. This makes newer properties more difficult to convert.
As with all major home improvement projects a terraced loft conversion will require building regulations approval. Don't be put off by this.
The building regulations are there to help you and to ensure that your project is completed to a decent standard.
When making your application for building regs approval you will work closely with your builders and the local councils >building control officers.
Don't make your application until you are sure you have covered all the bases as there is a fee to be paid and no-one likes to waste money.
Don't worry if your initial application is rejected there are usually a few small sticking points that are easily rectified.
A good tip when planning a loft conversion is to ensure that the quote you receive from your builder includes a 'successful building regulations application'. You will then not be liable for any extra costs generated from an unsuccessful application.
Unless there are exceptional circumstances, such as the property being situated in a national park or you are planning to raise the height of the roof, there shouldn't be any issues with planning consent.
If you have a mid terrace property and are looking to convert your loft than there really isn't anything much to worry about.
Of course every case is different but, generally speaking, there is nothing untoward or more complicated about converting the loft of a mid terrace house than there is with any other kind of property.
For more info see the related pages below
Structural calculations for loft conversions are of course hugely important to ensure safety and that the proposed plans meet building regulations
What is the difference between planning permission and building regulations approval for loft conversions ?
Using And Fitting Loose Fill Insulation In Your Loft