Normally it's the building owner that's carrying out the notifiable works who pays for Party Wall surveyor(s) - whether this is one surveyor acting for both parties, or the individual surveyors on both sides. There are some circumstances where the fees may be liable against both parties, such as if there is work being done on the Party Wall due to disrepair or costs have been unreasonably incurred by the adjoining owner during the process. The Party Wall surveyor will determine the liability and the appropriate fee within the award.