51.   A vapor barrier can be a paper or foil facing on a roll of insulation material or a sheet of plastic.

52.   A vapor barrier is an air stop, which stops the passage of air to the outdoors, therefore the passage of heat.

53.   A. A second vapor barrier is, indeed, verboten.

54.   Additionally, there are social barriers to taking advantage of them.

55.   Actually, the biggest barrier to coexistence is not anything Charles has said or will say, but what he does.

56.   But a new vapor barrier is not that difficult to install.

57.   But as the latest dispute showed, the barriers were formidable.

58.   But a racial barrier was in place by Saturdays when couples gathered to dance.

59.   But even now, people in remote areas often cannot speak Indonesian, and the linguistic barriers are immense.

60.   But he was too old for the major leagues by the time the color barrier was broken.