Thickness of floor joist!

[guran1]

Hello!

We are planning an extension and I have started looking for products to get an idea of what it might cost.

Of course, I will use a structural engineer to check that everything is sound, but does anyone know what thickness is needed for a floor joist that is 4m long and doesn't have support in the middle?

Grateful for answers

Guran1

 

[MathiasS]

45x220 is probably a safe choice for these spans. Install on cc30 to guarantee load-bearing capacity for all conceivable surface layers.