Filling holes in basement wall

[Stabbsson]

Hey!

I'm in the process of renovating the old boiler room and just knocked out 2 pipes that were for the previous oil tank, but now I need to fill in the holes.
What would you recommend? Fill in with larger stones/expanding foam/insulation and then plaster on the inside + outside for the last few centimeters?

 

[Klodsmajor]

How thick is the wall?
I would probably try to fit in a piece of cellplast and then plaster with Grundning röd A.

The alternative would be to utilize the hole that already exists and install ventilation?

 

[Stabbsson]

There's already a large supply air vent, so maybe it's not necessary to have 2 more

Cellplast and plaster sounded quite reasonable otherwise

 

[Stabbsson]

How thick is the wall?
I would probably try to fit a piece of cellplast and then plaster with Grundning röd A.

The alternative would be to utilize the hole that already exists and install ventilation?

I think it's 25 cm