Have a Mfg home I inspected. 4 years old, leaks into the home on both side walls (faces west.) The home is in Montana (Kalispell) It do get cold and snowy there. The overhang is 6-8 inches. Roofing looks good. Have neot been there while leaking. Could this be a mfg problem?
May also not be a mfg problem.
You have not provided location of leaks within the building envelope other than saying leaks into the home on both side walls.
could be from hammer holes in the exterior walls, don’t know because you have
not provided enough info
It is very hard to say from the information that you have given us. Your best bet is to locate a home inspector in your area and talk to them, and possibly have them look at the home and help point you in the right direction.
The OP said he/she inspected the property.
You are correct, sorry for the oversight.