| 摘要 |
<p>To construct a secondary wall abutting an existing wall (10), a guide unit is attached vertically to the existing wall. The guide unit comprises a. beam (20), attachment means (21) for attaching the beam vertically to the wall (10), and a slider unit (22) slidable vertically in the beam. The slider unit carries at least one projecting pin (51), from which a line is stretched along the line off the new wall to guide the laying of the next course of bricks. There may be several pins (51), with means (53-55) for adjusting their vertical spacing. The guide means may be attached to the wall by screwed plates (40), or plates (42) gripping into mortar gaps. The beam may comprise a first sub-beam (30A) attachable to the wall and a second beam (30B) carrying the slider unit and adjustably mounted on the first sub-beam.</p> |
