Eliminating the Internal Sealant for a Worry-Free Cutainwall Installation

by Curtis Meade

The most common problems glaziers encounter when working with conventional pressure-equalized curtainwall systems are found internally. These include unsealed or poorly-sealed end dams, pressure plates that don’t have the proper torque on the fasteners or interior gaskets that are cut short or not sealed properly.

Any breakdown of a curtainwall interior seal can create a void to the interior of the building that keeps the system from proper equalization. This will not allow the system to weep, and unwanted air and water can enter the building. All of these problems can be time-consuming and labor-intensive to repair. They can also be avoided by installing our Series 5800 curtainwall system. Following are instructions, to aid companies in the installation of this system.

The 5800 curtainwall system structural silicone gasket is a fabricated, flexible continuous frame with molded corners. These gaskets provide retention and front weather-sealing of all infill components. The gasket, which will last the lifetime of the building, can be installed in any weather, and is ideal for new construction or replacement of deteriorating zipper gaskets.
The 5800 curtainwall can be installed and removed easily. It is designed so the exterior gasket engagement dart interlocks within the aluminum extrusion. This design helps minimize under- or over-compression of the gasket—but visual inspection indicates easily if any corrections are necessary.

Installation
The glazing tools used are a dead-blow hammer, a deglazing tool for the removal of the gasket and a liquid spray bottle for lubricant application. The individually-packed gaskets will arrive on site with an identification number that identifies the gasket frame location on each elevation. Remove the gaskets from the polyethylene bag just prior to glazing. This will help prevent placing a gasket in the wrong location.

The horizontal mullions are designed to be notched over the vertical mullions and are attached by two tech screws. The vertical mullions are anchored the same as most curtainwall systems, with the use of standard M or F type anchors. Standard midspan anchors are used for wind load and dead load application. After mullions are set, the system is ready for the glazing process to begin.

Before glazing, the interior gaskets should be inserted into the reglet of all verticals and horizontals. The condensation drainage cord is located in its recess in the transom, and is passed through a hole in the side of the vertical mullion. Position setting blocks at appropriate locations, visually at quarter points. Now the opening is ready for glazing.
Insert the infill and align it so there is an even edge clearance around its perimeter. To facilitate gasket installation, a spray bottle containing a low-concentrate liquid soap solution or common glass cleaner can be used for lubrication. In freezing climates a small amount of ethyl glycol can be added to the soap solution. Series 5800 curtainwall gasket frames are sized slightly larger than the actual perimeter to allow for crowd-in and proper compression at each corner. Gaskets should never be stretched during installation.

Begin glazing by tapping all four corners of a gasket into the aluminum frame. Next, tap in the remaining gasket, starting each time from the center of a loop. Continue to halve each loop until the gasket is fully tapped into position. This process ensures that the gasket material is evenly distributed and that the corners fit snugly. If you have to stretch a gasket, it’s the wrong frame for that opening. Run your fingers over the gasket to feel for any uneven areas. Tap any excess into its correct position. The installation is finished at the head and sill by fitting a straight length of perimeter gasket. Use the same excess loop technique as previously mentioned for perimeter gasket installation. Remember, do not stretch the gasket.
The visual appearance of the finished system is critical. The four-way junction of gasket frames should be a tight fit, with no misalignment. Make a final inspection of the finished wall. Gaskets that have been installed incorrectly can be seen or felt, and then adjusted accordingly.

Deglazing
A significant feature of the Series 5800 curtainwall system is easy deglazing. Each gasket can be individually removed to allow replacement of single panels, or for the complete change of an elevation during remodeling. The silicone gasket engagement dart has to pass over a portion of metal extrusion at each intersection. This is made possible by an integrally-molded gasket corner dart.

Deglazing begins by gently easing the gasket corner dart out of its interlocking position in the aluminum. This is done by using a deglazing tool, which has a curved, smooth and rounded shaft. Working vertically, insert the point of the shaft between two gaskets, just away from the outer edge of the gasket corner. Ease the gasket corner dart out of the aluminum. The tool can then be inserted beneath the main run of the extrusion, and the gasket gently removed from the aluminum framework. Use the same procedure for the horizontal gasket length. Once a sufficient length has been eased out, the remainder can be removed by hand. Always remove the gasket at a right angle to prevent damage to the engagement dart. Continue removal by hand until you reach the next corner. The deglazing tool is used again to disengage the molded gasket corner dart. Continue this method around the rest of the opening until the whole gasket is removed. Examine the gasket for any damage, and then place it in a polyethylene bag and label with the location for later reference. The infill can now be removed for replacement or relocation.