Abstract: A instrument and method of applying house wrap to exterior walls. The instrument or tool or apparatus allows the roll of house wrap to be positioned with an axis of rotation substantially parallel with the wall. The house wrap can then be rolled and applied onto the wall as the apparatus is moved along the length of the wall. The apparatus can roll along an upper surface of the wall so that the apparatus need not be lifted. The apparatus also may have a guide wheel to maintain the house wrap roll at a substantially fixed distance from the wall.