I'd do something like this:
select bn.building_name ,
t.*
from ( select fat.building_id ,
sum( case when fat.percentage_used <= 0.10 then 1 else 0 end ) as group_a ,
sum( case when fat.percentage_used > 0.10 and fat.percentage_used < 0.50 then 1 else 0 end ) as group_b ,
sum( case when fat.percentage_used >= 0.50 and fat.percentage_used < 1.00 then 1 else 0 end ) as group_c ,
sum( case when fat.percentage_used >= 1.00 then 1 else 0 end ) as group_d ,
sum( case when fat.percentage_used is null then 1 else 0 end ) as group_e
from fact_table fat
join groups fts on tfs.dim_project_id = fat.dim_project_id
group by fat.building_id
) t
join fact_table bn on bn.building_id = t.building_id