Claims: Claims can be initiated by both parties involved. Claims are settled through negotiation, adherence to contract terms, or a mutually agreed  adjustment  in  the  contract  performance.  The  goals  of  both parties should be to ensure that claims are justifiable.

The reasons for owner?s claim can be the following:

•   Defective work by contractor.
•   Delays by contractor.
•   As a claims defence.

The reasons for contractor?s claims can be the following:

•   Late or defective information by owner.
•   Delay in or defect in free issue material by owner.
•   Changes in regulatory requirements.
•   Unknown site conditions.
•   Restrictions imposed on work method, including restrictions which cause delay or acceleration in contractor?s work performance.
•   Collateral work which leads to ripple effect for example concreting is planned to be done during fair season is rescheduled to adversely cold  seasons  (for  reasons  not  attributable  to  contractor)  which require heating arrangements impacting cost.

A claim is different from a change order. A claim is a quotation by the contractor requesting you to issue a change order. When you agree on the quotation it becomes change order.