Read the case carefully and answer the question set.

Laamia hired Tariq Construction and Design for several projects in building his home. For each project, the parties signed a written contract that was based on a cost estimate and specifications and that the required changes to the agreement to be in writing. While the work was in progress, Laamia repeatedly asked Tarig to deviate $($make changes$)$ from the contract specifications, which Tariq did. Laamia made payment for the changes on the request of Tarig each time.

One day Laamia asked 'Tarig to use durisol blocks instead of cinder blocks

specified in the contract. Tarig used the durisol blocks but demanded extra payment as the durisol blocks were more complicated and time consuming to use. Although Laamia had paid for the other deviations from the contract that she orally requested, she refused to pay Tariq for the substitution of the Durisol blocks.

Durisol and Cinder blocks are types of bricks used for building$)$

QUESTION:

Is Tariq entitled to payment? Why? Explain. Name the principle upon which you will base your answer and show how it applies to the problem.