Most of the temples at Mỹ Sơn were made of red brick, and only one (the temple labelled "B1") was made of stone.[28] Even the decorative carvings on the Cham temples were cut directly onto the bricks themselves, rather than onto sandstone slabs inserted into brick walls as is observable for example in the 9th century Cambodian temple of Bakong.
To this day, the construction techniques used by the Cham builders are not completely understood.[29] Issues that have not been completely resolved include issues about the firing of the bricks, the mortar between the bricks, and decorative carvings found on the bricks.