The Oldest Building....

....in Mytholmroyd (Nr. Hebden Bridge)?
Quite possibly. This house was originally a late medieval timber-frame building, rebuilt in stone in the early to mid 17th century. Now no longer a farm it is a Grade II* listed building.
It was originally called simply Mytholmroyd - and thus probably gave its name to the village.
The name derives from mytholm and royd and means the clearing at the junction of two rivers.

There is an earlier picture of it here.