can you copy another architects plans if he has retired?

The copyright in a work of architecture will vest, in the first instance, in the person who has been the author of the artistic design. The period of copyright protection for architectural works lasts from creation to 50 years after death of the author. Ownership of copyright in any architectural drawings in commissioned works will usually be determined by the contractual agreement between the parties. Ideally the contract will outline whether the copyright is assigned to the commissioning party and/or to what extent use was permitted under licence. In the absence of an agreement indicating otherwise, the first owner of copyright in an architectural drawing will, in the case where a work is commissioned from an architect, generally be that architect (provided the architect is not an employee of the commissioning party). Transfers of copyright are implied, generally, only where it is necessary to give business efficacy to the contract and the implied term satisfies the officious bystander test. In other words where it would be so obvious to all parties involved, it goes without saying. There may be limited circumstances where it might be argued that a transfer of copyright could be implied, where the commissioned work is unique - on the basis that the architect could have no other conceivable use for that commissioned work. The courts have provided some guidance as to how this may be established, including consideration of the price paid or requirement to pay royalties to indicate an exclusive licence. Of course, it will depend on the individual facts and circumstances of each case.

Copyright rests with the original architect ever up to 70 years after their death. Copyright would need to be purchased from the originator and full agreement to use same agreed by deed or contract.

No, not without the other Architect's permission, the copyright belongs to the other Architect while ever he/she is alive. After his/her death they legally may still be protected by copyright. However, if the other Architect's client has paid for the drawings, then the client has effectively bought the copyright and therefore is allowed to print the drawings and pass them onto the Architect requiring copies.

The original drawings are generally copyright protected. If they do not have a statement confirming the copyright position you can copy them.