(a) Except as provided in subsection (b) of this section or unless excluded or modified pursuant to subsection (d) of this section, in every sale, warranties are implied that, at the time of the delivery of the deed to a completed improvement or at the time of completion of an improvement not completed when the deed is delivered, the improvement is:

(b) The warranties of subsection (a) of this section do not apply to any condition that an inspection of the premises would reveal to a reasonably diligent purchaser at the time the contract is signed.

(c) If the purchaser, expressly or by implication, makes known to the vendor the particular purpose for which the improvement is required, and it appears that the purchaser relies on the vendor's skill and judgment, there is an implied warranty that the improvement is reasonably fit for the purpose.

(d) Neither words in the contract of sale, nor the deed, nor merger of the contract of sale into the deed is effective to exclude or modify any implied warranty. However, if the contract of sale pertains to an improvement then completed, an implied warranty may be excluded or modified wholly or partially by a written instrument, signed by the purchaser, setting forth in detail the warranty to be excluded or modified, the consent of the purchaser to exclusion or modification, and the terms of the new agreement with respect to it.