I. Curtain Walls
Curtain walls are façade structures that cover several building levels. They are load-bearing frames of metal profiles and glass or solid infill panels. The complex structure is typically attached to the load-bearing system of the building from the outside. However, a curtain wall can be placed between two slabs also. Common types of curtain walls include the stick-built, the hidden frame, and the point-fixed structures, but less commonly used or obsolete solutions also exist.
- Sandwich panel curtain walls consist of frameless metal-faced, thermally insulated sandwich panels. They are representative of the 1970s and 1980s. They are made rigid by pressing, folding, or corrugating metal, with glass panes built into the panels using techniques similar to vehicle manufacturing. These panels can be suspended from the load-bearing structure. Care must be taken to ensure proper sealing between the individual panels.
- Structurally speaking, the stick curtain walls (or exposed frame curtain walls) consist of posts and lintels, described as vertical and horizontal ribs. The vertical ribs or mullions are attached to the slabs or pillars using steel fittings with multidirectional adjustment. The horizontal ribs or transoms are connected to the vertical ribs by screws or welding. Glass panes or solid inserts are placed between these ribs, and the cover profiles of the ribs seal the joints. The visible ribs strongly define the façade and give it a rigid structure. They may protrude from the plane of the glazing or fit flush with it.
- Hidden frame curtain walls are structurally identical to the basic stick-built system. The difference is that the ribs are not visible and hidden behind the glazing. Delicate lines, also called sealing lines, appear between the glass inserts, making the glass façade more uniform.
- Unitised curtain walls incorporate the rib frame system into prefabricated elements for quick on-site assembly. The vertical and horizontal ribs form the frames, and the frame elements are assembled on site. Individual elements can be glazed or filled with different materials. Element sizes can be increased up to 4 x 4 meters using dividing ribs. Dividing ribs are necessary for changing materials within an element, for example, to create a panel with a solid parapet at the bottom and glazing at the top.
- Point-fixed curtain walls affix glass panels to the supporting structure at specific points using special fittings known as spider clamps. Glass panels can be fixed without drilling using clamp fittings to secure the panels at the corners or fixing the glass in holes. As with other types, point-fixed glass wall fasteners can be connected to reinforced concrete slabs or pillars, or fixed and stiffened with cables. Two cable solutions are:
- a wire rope net of horizontal and vertical ropes with point fastening elements at the junctions, or
- rope systems similar to vertical grid supports, where the wires are tensioned between the slabs and the fastening elements.
II. Skylights
Skylights are special windows for attic conversions in buildings with pitched roofs. They usually follow the plane of the roof, although there are products now that transform the windows into small balconies which protrude from the roof plane when opened.
Ideally, the distance between the rafters and the desired window size should be the same. It may be necessary to replace a rafter for larger windows. Conversely, smaller windows may require the rafter next to the window to be extended sideways.
The skylight frame jambs rest on the support structure of the roof covering. A cladding frame connects it to the waterproofing membrane, the roof tile, and covering elements. The opening can be outward or tilting, with lower and upper handle designs, depending on the position of the handle.
Installation of skylights
Skylights should be installed at the same time as the roof. However, it is often the case that skylights are installed later, for example, when the attic is converted. In either case, the skylight installation process is as follows:
- Place headers and jack rafters between the main rafters
- Cut and fold back the waterproof membrane
- Place mounting battens below and above the window
- Fast the frame to the mounting battens and roof battens, fixing the folded waterproof membrane
- Create a waterproof membrane channel above the opening
- Install the underfelt collar around the built-in frame
- Position the bottom apron flashing, lapping over the roof tiling
- Install all remaining covering elements of the flashing kit on the frame structure
- Install or re-install the roof covering (tiles) around the new skylight
- Position and adjust the window sash
- Install thermal insulation and a vapour barrier layer in the interior space
