Is it permissible to use bricks in building graves where an area of 25 meters is divided into several niches (luḥūd), and is it permissible to bury men and women in adjacent niches, or must they be separated?

There is no objection to purchasing a cemetery divided into individual burial niches (lahds), even if these niches are constructed from fired bricks (clay bricks) to prevent collapse. Although, it is preferable to use unfired bricks (adobe) or reeds. As long as each deceased person is in a separate niche, there is no harm in placing a man in one niche and a woman in an adjacent one. There is no requirement to separate the niches of men from those of women. What is forbidden is burying two people in one grave, except in cases of necessity.