course is molded, it is important to line up properly the molded members throughout the course. This may make some slight variation in the line of bed, but this variation is less noticeable when occurring in a bed than if allowed to show in the projecting molding. 5. Parking and backing up. (a) Parge the back of stone by plastering with a nonstaining mortar. (b) Proceed to back up the stone by building up the brickwork to the height of the course. 6. Slushing or grouting vertical joints. (a) Fill joints by slushing in mortar, working it into joints with the point of the trowel. All vertical joints should be slushed full. 7. Protecting stone. Place a narrow strip of ordinary building felt or rosin sized building paper into bed joints on top of stone. If band or belt courses. project, allow outer edge of paper to project at least an inch beyond the front of the stone, thus protecting the stone from mortar stains. CAUTIONS 1. Stones showing marked difference in texture should not be set adjoining each other. 2. Do not set as adjoining members in jointed courses stones the moldings of which do not line up properly. Where moldings have been inaccurately cut the inaccurate piece should be set so as to allow the cutter a slight projection in order that he may properly trim off that stone, making it line up with the other members. 3. Be sure that the vertical joints of all projecting belt courses are filled solidly with mortar. QUESTIONS 1. What unit should regulate the height of cut stone belt or band courses? 2. Where the profiles of one or more pieces of stone do not match up perfectly with the remainder of the stone in the course, how should these stones be set to rectify this difference? 3. Why should a molded, projected belt course have a greater depth on a wall than a plain band or belt course? 4. Why is it important to check the length of a section of wall before starting to set the belt course? 5. Why is the slushing or grouting in vertical joints in projected belt courses so important? Job outline sheet JOB NO. 10 Block-BL-III: Jobs calling for the setting of (architectural terra cotta and) cut-stone trim. Job specification 6-A: Setting, anchoring, and joining several pieces of cut-stone trim having plain or molded faces and cut with or without slight overhanging projections. Type job b: Setting a onepiece cornice or molded water table course. PRELIMINARY You have had experience in the previous lesson in setting a molded projecting belt or band course with a projecting wash. When such a course has RETURN FACE OF DIER OR PILASTER BASH 8" BUILDING PADER PROTECTION DURING ERECTION, M 8" PLAIN WATER TABLE where walls are reduced in thickness by piers or pilasters BUILDING PAPER ROUGH BOARDS, MOULDED WATER TABLE FIG. 31.-Sectional view of a molded water-table coping a greater projection and the stone is cut with a molded face in the form of a cornice, it is then termed a one-piece minor cornice. Such cornices frequently occur at the roof line of buildings where a parapet with stone coping is placed above the cornice. Also, a minor cornice with a wash top is often used in the lower story of buildings where the thick basement part of the superstructure wall is reduced to the thickness of a curtain wall between piers. A plain water table course or water table coping is illustrated in Figure 30. Another type of water table course molded as a cornice is shown in Figure 31. A minor one-piece cornice such as will occur in the upper portion of a wall is illustrated by Figure 32. A minor cornice course of this character is usually cut into sections from 2 feet 6 inches to 4 feet 6 inches in length and the stones are of such a size and weight as to require the use of some lifting device for raising and setting them in place. A gin pole or small derrick is commonly used for this purpose. The actual setting operations for a projecting, one-piece cornice, as taken up in this job, do not differ materially from the setting of NARROW STRIP OF SHEET ANCHOR H FIG. 32. A minor one-piece cornice belt or band courses described in a previous lesson. 1. Checking stone and measuring wall. (a) Measure the individual stones and compare the lengths with the setting drawing. (b) Compare the total length of the section of the wall already built with the over-all dimensions on the drawing. 2. Placing props. Place props in positions where needed. Since corner pieces have projections on both sides, the stone will have to be supported in place with props until anchors are set and bedded in the back wall. Such props are usually made of 2 by 4 inch or 2 by 6 inch timbers extending up from the sills of windows in the story beneath the cornice. 3. Preparing the bed. Spread bed of mortar evenly and place wooden wedges. Wedges placed on the outer edge are used to prevent the mortar from being forced out by the overhanging weight of the stone. 4. Raising and setting the cornerstone. Raise stone above the bed and lower in position. Stones of this size, that are intended to be handled by a derrick or other lifting equipment, are provided with Lewis holes cut on the unexposed part of the top bed. The stone is raised above the bed and lowered into position. (See technical sheet for description of the different types of Lewises used; also, a description of other fastening devices which may be used in lifting the stone, such as slings and clamps. 5. Setting intermediate stone. (a) Stretch line between corners. A line should be stretched from corner to corner to serve as a guide for lining up the intermediate stone. (b) Set stone to level with joints properly spaced. 6. Grouting joints. (a) Parge back of stone. (b) Calk face of joints and fill with mortar. Vertical joints between large stones of this character are usually grouted after all the stones have been set. Preceding the grouting, the backs of the stones are parged and any metal anchorage required is put in place and the brick or other backing built up level with top of stone. The method usually followed in grouting the joints is to calk the profile of the cornice with manila rope yarn or oakum, the grouting being poured in from the top bed and worked into place with a steel rod or trowel. The calking is removed after the grouting has set and the outer joints are then pointed up. 7. Protecting stone. Fasten boards to zinc strips. If the cornice projects for some distance, a strip of zinc which was bedded into the top joint is used to hold the boards in place to serve as a protection for the cornice. Figure 33 illustrates the method of fastening this board in place. CAUTIONS 1. Every effort should be made in setting the cornice stone to lower the stone to the correct position so that no adjustment is required. If misplaced, the stone will usually have to be lifted off the wall and reset, thus making it necessary to make a new mortar bed. 2. Care should be taken to see that the anchors in the corner stone are properly bedded into the backing wall. QUESTIONS 1. Why are wooden wedges thoroughly wet before placing in the mortar bed? 2. Why is it advisable in setting a minor cornice to leave the filling of vertical joints until all the stones have been set? 3. Why is sheet zinc used in preference to other metals in holding boards in place over wash of cornice? Job outline sheet JOB No. 11 Block-BL-III: Jobs calling for the setting of (architectural terra cotta and) cut-stone trim. Job specification 6-A: Setting, anchoring, and joining several pieces of cut-stone trim having plain or molded faces and cut with or without slight overhanging projections. Type job c: Setting cut-stone cornice consisting of two or more members. PRELIMINARY So far your experience has been limited to setting individual stones and building around them with brick or tile. You have also set horizontal pieces of stone to a line. In this job it will be your first experience in setting stone upon stone in a horizontal course made up of at least two pieces. Figure 33 illustrates a section of a twopiece cornice. In setting such a course the vertical joints of the two members are staggered so as to break joints. Usually the vertical joint in the upper piece occurs either at or near the middle of the lower piece, except where it is desired to have the cornice appear as if cut in one piece, in which case the joints of two members are made to line up. The operations in setting a two-piece cornice are practically the same as included in the two previous lessons. Only additional information not found in the previous jobs is included in the operations listed with this outline. 1. Checking length of stone and wall measurements. 2. Adjusting lift device. Place gin pole in best position to properly handle the stone and see that it is in working order. As stone cornices of this type, consisting of two pieces, are usually of a size that make them too awkward and heavy to handle and set without some hoisting device, it is customary for such stone to be set with a gin pole, breast derrick, or other suitable lifting derrick. 3. Preparing the bed and setting the corner pieces. (a) Prepare and even mortar bed of proper thickness. (b) Raise corner stone into position above bed. |