This paper investigates the performance of scirpus grossus (SG) fiber and fiberglass (FG) as ceiling material. Scirpus grossus was extracted by peel method. Mixture containing scripus grossus, fiberglass and carboxymethyl cellulose (CMC) was cast with thickness of 7.5 and 15 mm of both fibers namely as 7.5SG, 15SG, 7.5FG and 15FG and undergo tensile strength test, flexural strength test and water absorption test. The result show, 7.5FG has the highest water absorption compared to SG7.5 with difference of 21% whilst for ceiling with thickness of 15 mm, 15SG show the lowest value of water absorption compared to 15FG with 17% of difference. Meanwhile, flexural strength of both thicknesses was comparable for both fibers. It is concluded that, natural fiber shows a good potential to be explore as ceiling material for energy efficiency building application in future for tropical climates zones area.