Wood beams (Norcot RG30)

Hi all I would like to ask if anyone have spare wood beams for repairs on shed please?? The guy who'll build the shed up and repairing it said that I'll need 2inch by 4inch wood beams, I really appreciate your help, I guess it might be different size as he might be able to do some possible magic 🦹Lol many thanks Salma 🍀