Recommendation for glass dome installation

Recommendation for glass dome installation

There are several systems to install glass domes, either only for a skylight with a single glass or large and extensive covers with glass specialties, in general regardless of size, usually the glass is supported on a structure, either aluminum or steel and even in some cases on wooden beams, it should be noted that these structures generate a lot of movement either by the structure itself, by wind or by expansion of the materials. There are at least two alternatives for installation and fastening. One of them can be using the mechanical fastening elements with aluminum profiles or sills or with tape and sealant, both structural and weatherproof sealant, which will be explained in a generic way below.

For this system you must first know the type of glass that is involved, if the glass is monolithic either “raw”, “cut” “float” (not recommended in domes for safety) or tempered or if it is a laminated glass or may have some solar control treatment and even if it is a glass module. Insulated (double glazing) because if these last three concepts (laminated, solar control and insulated) are met, a neutral curing silicone is required. What the system does contemplate, whatever the glass is, is the use of separating tape and backing.

The aspects and products to consider for the correct choice of sealant and installation of the glass dome system are:

pens® silicone 100% architectural degree

pens® construction II

UltraGlaze™ 4000

GT-900 Tape or ST-200 Tape

Sof-Rod Backing

MST-400 Tape

Additional considerations

For these systems, wind pressures and suctions, positive or negative slopes must be considered, the above phenomena can lift or displace the glass, so a structural sealant such as UltraGlaze™  4000 is required to work as a chemical fastener between the frame and the glass, In the case of airtightness, pens® construction II sealant is generally used in outdoor joints where the material and the structure have a high coefficient of expansion, contraction and movement, the ST-200 tape serves as a separator between aluminum and glass, creating a cavity to inject or extrude the UltraGlaze™  4000 structural sealant, and it also works as a temperature dissipator. As a complement, the sof-Rod backing is used in the glass-to-glass or glass-to-wall joints, together it is called the glass dome sealing system.

Installation steps

It is important to consider that the sealants will have adhesion directly on the surfaces on which they are applied, so they must be firm, dry, clean, free of dust, grease, oils, water, so then you must carry out a cleaning with the technique to two cloths before the placement of the product.

This technique consists for smooth surfaces, such as polycarbonate, in passing a lint-free cloth (preferably cotton and colorless) dampened in isopropyl alcohol over the surfaces, polycarbonate and frame, and immediately after, pass a dry cloth, so that the dry cloth dries the alcohol before evaporating, in order to favor the adhesion of the products to the surfaces.

It is recommended that the frame is made of natural aluminum or if the structure is made of carbon steel, a deep cleaning, primer and electrostatic paint is recommended.

Once the surfaces are clean, proceed to place the ST-200 tape around the perimeter and intermediate uprights, in a continuous manner. If the mullion or frame receives two panes of glass, two ST-200 tapes must be placed in parallel, and each pane of glass must have its own tape.

Once the ST-200 tape is in place, the blue liner is removed from 1.5 to 2 cm in one of its corners and folded towards the internal or external part, so that it looks like a flange. Next, the glass is placed and centered, respecting the joints between panes and between glass walls, the minimum recommended joint between materials should be ¼” or 6.35mm. Once the glass piece is centered, the blue liner is removed from the corners, pulling the tab and removing the blue protective liner. As the blue liner is removed, pressure is exerted on the glass and the tape around the perimeter and in between so that it works properly.

The next step, on the inside and underneath the glass, is to mask the frame and glass with masking tape and “inject” UltraGlaze™ structural sealant between the space formed by the glass and the profile, around the perimeter and in between continuously. This should be done on the perimeter of each glass module.

Now, the next step is the seal in the joint formed between glass and glass, as well as the joint between glass and wall on the outside or also called weathering.

In this step a separation or joint between materials of at least ¼” or 6.35mm must be considered. The Sof-Rod backing is placed first, this should be at least 1/8” larger or equal to the joint or separation between materials, which should be placed slightly tight, once installed, we proceed to mask the glass with masking tape in order to delineate the joint, with the above, Once installed, we proceed to extrude the Pens Construction II sealant in the joint to be sealed, in a uniform and continuous way, filling perfectly well the cavity, once this work is finished, we have to carry out the review with a plastic spatula in the opposite direction to the application and finally the masking tape is removed.

For best results, it is recommended that the application of the sealants is done when the material(s) has an average temperature. Respect the minimum section and joint ratio.