ᐅ Basement insulation with varying insulation thicknesses

Hello,

quick question... my basement was insulated with 120 mm (5 inches) XPS. The general contractor probably miscalculated, and they ran out of insulation boards. Now the top layer of insulation is still missing. Yesterday, a new shipment of insulation boards for the basement arrived.

However, from a different manufacturer and only 100 mm (4 inches) thick...

Can they really use two different insulation thicknesses on the same wall, or not? I’m just an amateur, but it seems very odd to me...

Looking forward to your advice.

Eierpiepe schrieb:

He can’t apply two different insulation thicknesses on one wall, or can he?

With which insulation values? 100mm (4 inches) insulation can insulate better than 120mm (5 inches). How is the transition from thicker to thinner implemented?

Thermal conductivity is identical at 0.037.

Is this information sufficient?

I’m not sure how he plans to design the transitions; I just wanted to know if this is basically feasible and what needs to be considered.