ASME IX defined in QW-109.2 build-up of base metal (restoration of base metal thickness).
Test of test required are given in QW-202.3
Test coupon, WPS qualified on groove weld shall be applicable for weld repair, there is no limitation on the thickness of base metal and deposited weld metal for fillet weld.
For other than fillet weld, thickness range for base metal and deposited weld metal are in accordance with QW-451.
This build-up may be with the chemistry different from the base metal chemistry which has been qualified via a standard butt-weld test coupon.