What is the difference between acrylic plastic and Plexiglas?

None. Plexiglas is a brand name for acrylic plastic

What is Low-E glass?

Low-E (low emissivity) glass was originally developed for energy efficiency, but has the additional benefit of blocking heat gain as well as heat loss through a skylight. It provides a comfortable light without darkening the skylight such as in the use of tinted glass.

What is the difference between tempered glass and laminated glass?

Tempered glass is a monolithic heat treated piece of glass, one step beyond heat-strengthened glass. It is very strong, but if broken, can explode into thousands of tiny pieces.

Laminated is two pieces of glass with a PVB plastic layer in between (safety glass), which is designed to hold in place when it breaks. It has the extra advantage in that it is a very effective block of ultraviolet light which is the leading cause of fading

What are curb-mounted skylights?

Skylights that have a curb built up to support the skylight as opposed to a deck mount that has a curb built into the skylight and attaches to the roof deck directly. A curb is simply a wood box that is built higher than the roof and sealed to become part of the roof. The skylight is then dropped over the curb and attached from the outside

What is a weep system?

The internal gutters that allow any water that enters to run a path to exit the skylight system.

What are some of the different types of skylights?

Structural Skylights

  • Single Slope Skylights – also referred to as “Curb Mounted Skylights,” are a single plane skylight, commonly found built into a roof. Single Slope Skylights are the simplest of all skylight designs. They provide a refreshing environment without adding much stress to a building’s structure.
  • Ridge Skylights – is an excellent way to allow a significant amount of light into the structure, much more so than a comparably sized window. Ridge skylights can be glazed to help shield against UV radiation and increase the heat retention.
  • Pyramid Skylights – are typically mounted on curbs on flat roofs and generally have 4 sides with one or more pieces of glass or polycarbonate glazing per side joined by hips to form a peaked skylight. Standard pitch is 6:12 with many custom options available.
  • Vault Skylights – provide an economical and efficient way of introducing daylight and spaciousness to a lobby, atrium or the interior of a building. They can also be used for a wide variety structures including: entrance and walkway canopies, cover between buildings, hallways and corridors.
  • Octagon Skylights – function almost like a sundial throughout the day, permitting lights from a variety of angles.

Standard Skylights

Curb Mount Skylights

  • Curb Mount Skylight is designed to mount on top of an existing flashed roof curb.  The key to proper sizing is taking the correct outside curb dimension (OCD).

Self-Flashing Skylights

  • Self-flashing skylight is a skylight that comes with a built-in roof curb. The curb is a 4″ tall aluminum extrusion that is integrated with the skylight frame. The key to proper fit is to measure the Rough Opening (RO) in the roof.

What is structural caulking?

Caulking between two pieces of glass that are next to each other.

How often should the weather-seal washers be replaced?

This varies on the local conditions, normally when they develop cracks, is when they should be replaced.

Why is structural caulk joints used on some skylights while others use horizontal pressure caps?

Structural caulk joints are used in place of horizontal pressure caps to facilitate proper water shed.

Why install, repair or upgrade a skylight?

Using less energy saves money and is environmentally friendly. Skylights will save you money on energy cost and brighten your environment.

Repair or Replace?

In most cases a skylight can be repaired rather than being completely replaced. We have found that most building owners or property managers are satisfied with their current skylight system, but are unaware of proper maintenance procedures. MEI can provide maintenance plans that can save added expense of a repair or replacement skylight system.

What are some of the causes of skylights leaks?

Many leak problems begin when water makes it way under gaps in the skylight itself, into the flashing around the skylight, or the flat roof membrane that goes up the curb. When this water freezes, it expands causing the gap to expand. After a few seasons of this expansion and contraction, the skylight will start to leak.

Another cause of skylight problems is improper installation. Improper flashing installations accounts for the large majority of skylight problems which is why it is always recommended that a professional install any type of skylight.

Other common problems that can come from skylights include condensation from poor insulation, too much heat, mold or mildew from constant dampness, roof membrane can rot and air can get in resulting in decreased energy efficiency.

What is crazing?

Crazing is small cracks which develop into full-fledged cracks due to stresses caused by the expansion and contraction of the acrylic. Acrylics are produced using petroleum distillate which causes the material to eventually dry out, the resulting crazing.

What is Dow Corning® 795 Silicone Building Sealant?

Dow Corning® 795 Silicone Building Sealant is a one-part, neutral-cure, architectural-grade sealant that easily extrudes in any weather and cures quickly at room temperature. It’s versatile – high performance structural glazing and weather-seal, virtually unaffected by sunlight, rain, snow, ozone and temperature extremes of -40°F (-40°C) to 300°F (149°C). Excellent unprimed adhesion to a wide variety of construction materials and building components, including anodized, alodined, most coated and painted aluminums.

What do the initials IMA stand for and what does it mean?

IMA stands for Impact Modified Acrylic – it is up to 30 times stronger than double-strength window glass and 50 times stronger than polished wire glass or other glasses, making it an excellent choice for skylight replacement.

What are outside curb dimensions?

Outside curb dimensions are measured to the outside edge of the roof curb. These dimensions are the exact outer-most edges of a pre-existing roof curb.

What is a breather tube (Capillary Tube)?

A breather tube is a small hollow tube found in insulated glass units. The function of a breather tube is to allow air pressure to stabilize during transportation of skylights and windows. Because these tubes are hollow they must be crimped (closed) after or just before installation to keep moisture from forming between the panes of glass. If these breather tubes are not closed properly it could void the glass manufacturers’ warranty.