Methods of making nonwoven mats having good strength after being scored and folded and particularly useful in making lightweight, compressible ceiling panels are disclosed. The mats also have excellent flame resistance. The mats include a blend comprising a major portion of glass fibers and a minor portion of man-made polymer fibers, the fibers being bound together with a cured binder containing a homopolymer or copolymer of polyacrylic acid and a polyol. The binder bonding the mat together can be cured to only a “B” stage to produce thermoformable mats or more fully cured to produce mats having the properties described above.