Femto-cells have been proposed as a throughput boosting solution for indoor users, but a key challenge is how to resolve the interference between neighboring cells. This paper proposes a distributed self-deployment solution to improve the indoor throughput. This investigation considers where to optimally place a femto-cell in a multi-room indoor environment. The novelty of the research is that a closed-form Femto-cell placement expression has been derived, which can maximize the throughput of the indoor building given knowledge of a few key statistical network parameters. The benefit compared to blind placement is that it can achieve a throughput improvement of 20 to 50%. The solution has a high placement error tolerance of 10% of building size. Another benefit is that the optimal solution can maintain an approximately constant level of throughput, irrespective of the indoor building size.