Parametric modelling - OpenSCAD (which you mention) is commonly used for that style of handwritten arithmetic and has a few python-based alternatives like CadQuery. In GUIs, FreeCAD has an architecture module that aims to be fully featured (never used it), but for just parametric drawings, SolveSpace is lightweight and probably more pleasant to use.
OpenSCAD is completely the wrong tool for the job. You want a graphical parametric modeller. The only vaguely decent FOSS one is SolveSpace. It's a bit lacking for actual CAD (no fillets!) but it works fine for 2D layout.
I have actually used it for that (actually I did full 3D modelling of part of my house) and it worked ok, however I would say that measuring things with a laser and copying them into CAD is not a very accurate way to do things.
You will end up with large accumulated errors, and most houses are not as square as you think they are.
I haven't ever used one but I suspect those phone based AR measurement apps have a good chance of being more accurate.
