Malaysia is located in the equator, with a hot and humid climate. The highest temperature recorded during the day was 39 C, which leads to discomfort among building occupants, in particular, residential buildings, where indoor thermal comfort is of a higher priority compared to other types of buildings. Hence, the thermal performance of the residential roof assembly needs to be improved to lower the indoor temperature and, accordingly, maintain the level of indoor thermal comfort. In view of the need to improve the thermal performance, a silica-aerogel-incorporated rigid board roof insulation material for residential buildings was developed using kapok fibre, high density polyethylene (HDPE) and silica aerogel. The thermal conductivity of the material was measured. The sample with 4 wt. and 5 wt. of silica aerogel content obtained the lowest thermal conductivity of 0.04 W/mK. Silica aerogel content of above 4 wt. did not result in further reduction of the thermal conductivity. Therefore, it can be concluded that the optimum silica aerogel content for the sample was 4 wt. . Building-Information-Modelling (BIM)based thermal-energy performance evaluation of the material was performed by generating temperature and cooling load data using Integrated Environmental Solution-Virtual Environment to validate the thermal-energy performance of the material, by installing the material within the roof assembly of a residential BIM. Findings indicate that the material can potentially be employed in the future as a roof insulation material to maintain the level of indoor thermal comfort among residential building occupants. © Published under licence by IOP Publishing Ltd.