sorry to know that. it has nothing to do with seller

if the seller did not intentionally hide information when the house was sold. (it is a new problem so I think the seller did not know this when the house was sold.)

When you buy the house from the seller, you should have obtained the warranty from the seller. Normally, the builder covers a few years of warranty for construction problems. you first need to find out the warranty document (check with the realtor) and then go to talk with builder (hope the builder is still in business and you can find it). You can talk to your home insurance as an alternative.