Hello. We have hired a construction company that "guesstimates" whether we need a support beam to whether we need a substantial one. I don't think it's up to us to perform that calculation. While waiting to get hold of someone who can calculate, I am still throwing one out here. The opening will be 485 cm in the kitchen. There was previously a beam 70 mm in height and 80 mm in width. Attaching some pictures here. They are 240 in height. There is a small plaster wall resting on the floor above, but nothing else weighing it down. Grateful for any advice and tips 
Based on what can be seen in the pictures, which isn't much, I would guess that a rather substantial beam is needed. However, if you want some sensible answers, you probably need to upload some plans as well.
Regardless, you will need a structural engineer to take a look at it.
Regardless, you will need a structural engineer to take a look at it.
It is neither you nor the construction company that should "killgissa," but an engineer who should calculate.
But it sounds like this is a modification of the house's load-bearing structure. Then you need to file a construction notification. And then you will need to have some form of drawings.R RedAir said:Unfortunately, there are no drawings for the house built in 1962
If you try with a bit of estimation from the pictures you posted, it looks like the floor above the opening spans at least 6-7m. And you're planning to open a total of 4.8m? The floor must normatively withstand 200kg/sqm plus its own weight. So on an area of 30-40 sqm, you get a load of around 7-8 tons. Half of that load impacts the beam.
The quote you received. It's a bit strange that someone can quote a beam before there are construction drawings/calculations. I'm a layman, but I guess you need a steel beam if there's going to be any height left under the beam. Besides the beam itself, there must be something that can support the beam. And the foundation must also be able to withstand the point load that occurs where such pillars stand.