Hello! I need advice and opinions on my basement project. I live in a 1930s house with an area of 85 sqm with a basement of 45 sqm (secondary space). The basement is completely uninsulated, meaning the basement floor is original and should be demolished and insulated according to all the rules. The part that is intended to be excavated is about 25 sqm, here it is intended to become a living room/guest room/storage. The remaining space is a fairly new bathroom/laundry room (2008) and cold storage (here only surface renovation will be done). Unfortunately not excavated here 
Why demolish and dig?
@The old garage ramp still remains inside the basement and must be removed.
@Sewer lines from the 1930s, no avoiding them.
@Cold as hell on the floor, 14 degrees (20 up in the ceiling) last time I measured.
@The electricity is downright dangerous and needs to be replaced throughout the basement.
The problem is the drainage, done in the mid-90s, uncertain function, and the previous owner skimped on the insulation.
Is it worth spending 100k SEK on a new slab with water-borne underfloor heating when the walls are uninsulated??
Do you think the underfloor heating can maintain 21 degrees??
I must emphasize that drainage is not an option as the hedge towards the street must be removed, a large veranda must be taken down, and a cast staircase likely needs to be demolished..
Why demolish and dig?
@The old garage ramp still remains inside the basement and must be removed.
@Sewer lines from the 1930s, no avoiding them.
@Cold as hell on the floor, 14 degrees (20 up in the ceiling) last time I measured.
@The electricity is downright dangerous and needs to be replaced throughout the basement.
The problem is the drainage, done in the mid-90s, uncertain function, and the previous owner skimped on the insulation.
Is it worth spending 100k SEK on a new slab with water-borne underfloor heating when the walls are uninsulated??
Do you think the underfloor heating can maintain 21 degrees??
I must emphasize that drainage is not an option as the hedge towards the street must be removed, a large veranda must be taken down, and a cast staircase likely needs to be demolished..
Hello Pelig! If I decide to go ahead and break up the entire slab, it will need to be excavated and insulated. The sewage system is located in or under the basement floor. The alternative, if it even is one, is to break up parts of the slab and use self-leveling compound, then lay tiles, but then slippers are a must. But the question is whether the underfloor heating can manage to heat up the entire space when the basement walls are uninsulated? It feels awkward to install heating pipes and hang radiators afterwards.