Hello. We hired a contractor to build a pool. They...

If your request is related to the presence of defects in the pool, here is the following information:
You can first ask the contractor to repair the defects, and if he does not respond to your request, you can take legal action to force him to repair these defects and obtain compensation for the damages.
It is recommended that you consult a lawyer to help you properly initiate the necessary legal action.
Here is the text of the UAE Civil Transactions Law relevant to your claim:
Article 877
The contractor must complete the work in accordance with the terms of the contract. If it turns out that he/ she is doing what he/she undertook in a faulty or contrary manner, the employer may ask for immediate termination of the contract if repair of the work is not possible, and if repair is possible, the employer may ask the contractor to abide by the terms of the contract and correct the work within a reasonable time. If time has elapsed without the correction being completed, the employer may ask the judge to terminate the contract or authorize the judge to appoint another contractor to complete the work at the first contractor's expense.
Article 878
The Contractor shall be liable for any damage or loss caused by his act and manufacture, whether or not due to infringement or negligence, and the warranty is excluded if it results from an accident which cannot be avoided.