Integral damp-proofing involves treating building walls and floors during construction to prevent moisture from passing into interior spaces. There are various methods of damp-proofing including membrane damp-proofing, integral damp-proofing, surface treatment, guniting, and cavity wall construction. Integral damp-proofing works by including waterproofing materials within the concrete itself during construction, giving the concrete a waterproof quality through either hydrophilic or hydrophobic systems. Hydrophilic systems use crystallization technologies while hydrophobic systems use fatty acids to block pores in the concrete.