Lately, wireless networks have gained acceptance for home networking. Low cost installation, flexibility and no fixed infrastructures have made it possible for in-building networks to rapidly adopt this technology. In this paper we introduce the use of mobile ad-hoc networks (MANETs) for large in-building environments, such as hospitals, government buildings, office and industrial buildings, etc. Thus, we adapt their protocols and algorithms, relaxing some restrictions that are inherited from traditional ad-hoc networks scenarios (battlefield, catastrophic disaster, etc) to better fit the specific characteristics of this new application field. In particular, we propose a routing algorithm oriented to improve the performance of MANETs for in-building networking.