Question

all of the following are clues that insulation may have been added in a flat roof except
plugged holes in roof coverings or ceilings
vents added to the roof
a higher - than - expected roof surface temperature in winter
extra thickness to the roof
a lower ceiling height than expected
question 24
which insulation is controversial with respect to health issues?
polyurethane
polyisocyanurate
urea formaldehyde
phenolic board
vermiculite

Explanation:

Answer:

(1) C. a higher - than - expected roof surface temperature in winter
(2) C. urea formaldehyde