In some provinces in Indonesia, like West Java, fired clay and unfired soil lime bricks co-exist as non standard bricks. Low rise buildings and rural houses in Indonesia are often constructed with non-standard bricks. The paper discusses strength-time relation of unfired bricks reinforced with and without natural fibers. Untreated and treated coconut fibers with three different lengths (1 cm, 2.5 cm and 4 cm) were prepared for bricks reinforcements. The effects of 4% non-uniform fiber addition, which constitutes 1/3 part each of 1 cm, 2.5 cm and 4 cm average fiber length, was investigated. Absorption of the bricks was evaluated. For all type of bricks, up to 90 days compressive strengths are almost stable but bending strengths rapidly decrease with time. The results show that unfired bricks added with treated fiber resulted in better performances compared to those added with untreated fibers and without fibers.