No liability for the contractor?
In many contracts there are well-hidden phrases such as «...otherwise any guarantee for material defects or defect of title is excluded...». With this, the contractor is saying nothing else except that he is liable only for those explicitly stated characteristics of the house (such as for specifically called out appliances and kitchen equipment).
Assignment of defects
Another tricky issue is the exclusion of liability in conjunction with the assignment of defects. That's because in the same contracts you often see that «the contractor assigns claims of guarantees to the ordering party.» With this phrasing, the general contract declines any liability for the work of individual craftsmen. In legal circles there is no agreement whether or not a general contractor can assign defects in this way at all.
Consequences of the assignment
Be that as it may, for home purchasers such an assignment is of fatal importance. That's because when it comes time to file a complaint, the buyer must first confront the question of which company is responsible for which work, and he must contend with every single subcontractor, craftsman or supplier to get the defect corrected.
In addition, certain warranty rights are already forfeited. If, for example, the house foundation laid at the very beginning proves defective and no complaint was raised about this issue, the buyer has hardly any chance of prosecuting the responsible party.
No liability with «previously owned»
On the other hand, such exceptions from liability are normal for existing, older buildings. If, shortly after moving in, the heating system fails or the roof proves to have leaks, you can hardly expect to be able to ask the seller to pay for the repairs.
If you're dealing with new construction, however, you as the buyer should be aware that the contractor or seller can be held accountable for any defects in the construction.