Typical dimensional tolerances for cast stone are the numerically greater of plus or minus 1/8″ and length/360. This applies to all sectional dimensions; length, twist, square and camber.
Dowel hole and insert locations in the formed sides of pieces can be cast fairly accurately, within 1/8″. Additional tolerance, totaling 3/8″ must be allowed when they are located in the back or unformed side.
When assessing individual stones for tolerance, the setting tolerances of plus or minus 1/8″ (allowable out of plane from adjacent unit) must also be taken into consideration as shown. This tolerance also applies to flashing grooves, false joints and similar relief’s.