ᐅ Re-roofing: Yes or No?

This concerns the renovation of a semi-detached house built in 1980.

It will be a complete renovation except for the exterior walls.
Currently, I am considering the roof. A roofing expert said the roof is still in good condition.

However, I am thinking that since there will already be a lot of mess, it might be a good opportunity to address it.

The main reason for considering this is insulation. The roof currently does not have a proper underlay membrane. I keep reading that it is hardly possible to achieve good insulation from the inside only. What do the experts think?

The roof has a total area of about 120 sqm (1,290 sq ft). Are there general rules of thumb regarding the expected costs?

Since it is a semi-detached house, could we choose different roof tiles than the neighbor? How is the transition handled in that case?

Replacing the roof covering is quite expensive. It’s not cheap.
I would ask for a quote for just installing insulation, and then one for a complete job.
If a professional installs the insulation from the inside, it should work well.

Before you tackle this, I would first talk to your neighbor to see what they think about redoing the roof covering. Maybe they would join in if you really want to go ahead with it.

It is best to collect offers from two to three companies, with coverage and only one layer of insulation. As Koempy already mentioned, a roof like this does cost quite a bit of money…