________ is a semi-rigid material and it forms an excellent impervious layer of damp proofing.
(a) Hot bitumen
(b) Mastic asphalt
(c) Bituminous felts
(d) Metal sheets
I have been asked this question in my homework.
The above asked question is from Dampness in section Damp Proofing, Water Proofing and Termite Proofing of Construction & Building Materials