Unfortunately, another new problem with my pool: ig gunite, built in fall 2010. Recently, I noticed the joint under the coping above the waterline tile cracked open about 1/8 to 1/4" around the perimeter of the pool between the deep end skimmer and the diving board. Coping sounds hollow when tapped. My pool builder plans to fill in cracks this fall, then remove the affected coping next spring and fix it back down properly. He feels that groundwater has been getting under the decking, and that a corrugated pipe drain covered by gravel along the pool deck edge would prevent water from continuing to cause the problem. Landscapers, who claimed to have a lot of experience completing projects around pools, did not put a drain there. Instead, what I have is a grass yard that slopes down slightly from my house deck towards one side of my pool deck. The rest of the sides of the pool deck probably drain adequately and seem unaffected. I remember questioning the designer repeatedly about whether the mild slope towards the pool would cause a problem with groundwater flowing towards the pool, but he was sure it would not. There definitely has not been any mud washed into the pool this summer when it rained, so I don't think the grading is too bad, but probably not good enough.
My question is this: will a drain be enough to solve this problem with the water getting under the deck or do I need to pave the whole grassy area and put in a drain. I'm not sure that a single 4" drain along the edge of the pool will be enough. I'm sure this will be hard to answer without a picture. If it would help, I can try to take one in the morning. As much as I hate to do any more construction, I don't want to do less than the full job to get the problem solved.
Thanks in advance for your advice.