building and timber sizes

[climber101]

Hi,

looking for joists in C24 175x44 and 200x50mm. Do you commonly get regularised sizes with those exact dimensions - if not could you advise nearest sizes i am likely to get either slightly under or slightly over those two sizes please.

Many thanks

 

[Deluks]

About 3 mil each way is poss, depending on where you get them from. It's nothing in practical terms, as long as you get them all from the same place.

 

[^woody^]

C24 is not common, unless at the larger specialised merchants, and I suspect the uncommonness may men unregularised too. It all depends on the merchants supplier

Why should specific dimensions matter for first fix timber?