Posted by Kat Wiseman on July 29, 2019

Frequently Asked Questions for VELUX Professionals


Whether you're new to the skylight industry, VELUX products, or just roofing in general, we're sure you've got some questions! And even if you've been on the job for years, there's always more to learn. That's why we've compiled some of the most frequent VELUX-related questions asked by professionals in the industry.

Check em out:


Building & Installation Q's

What is an Instant Light Shaft?

When it comes time to install a skylight in a house with an attic, the Instant Light Shaft is VELUX's faster, cleaner alternative to traditional drywall installation. It's also more efficient time-wise and more cost-effective. Check out this video to see how.

How many skylights can be installed with one roll of ZOZ 216 VELUX Adhesive Underlayment?

One roll of the ZOZ 216 VELUX Adhesive Underlayment is 21 feet long by 9 inches wide, so the number of skylights that can be installed will depend on the size of the skylights you're installing.

What's included with the VELUX Sun Tunnel® Skylight?

The VELUX Sun Tunnel® Skylight comes packaged with everything you need to complete a roof-to-ceiling installation: the dome, flashing, tunnel, hardware, step-by-step instructions, and labels. There are, however, no tools in the kit, so you will need to use your own during installation.


Flashing Q's

What flashing do I use to group skylights together?

VELUX Combi-Flashing™ is engineered to use on skylights grouped together on roof pitches that are 14˚ (3:12) or greater. EKL Combi-Flashing™ is designed for thinner roof materials, like shingles and shakes, and EKW Combi-Flashing™ is for higher profile materials, like Spanish tile.

What flashing do I use with a metal roof?

For ribbed or standing metal roofs, use VELUX's Metal Roofing flashing, coded EDM. These flashing pieces interlock with roofing material and its sill apron features pliable pleats that form to the roof.

What flashing should I use with Fixed Curb Mounted Skylights?

VELUX's step-flashing system, ECL, is used with curb-mounted skylights on shingle/shake roofs. For curb-mounted skylights on tile roofs, our tile flashing ECW system is available. For other roofing materials, you'll need to use a custom flashing solution, which you can learn more about on our Skylight Flashing Kits page.

What spacings are available for Combi-Flashing™?

For shingle roof applications, Combi-Flashing™ is available in 2.5", 3", 3.5", and 4" spacings. For tile roofs, 4" spacing is available.


Technical Q's

Are VELUX skylights UL-approved?

VELUX's electric- and solar-powered skylights are UL-listed for the electrical components. They're listed under the UL file E82681.

What is the ICBO number for VELUX skylights?

For VELUX skylights, the ICBO number is IAPMO UES #0199.

What is the STC rating for VELUX skylights?

The STC rating for VELUX skylights is 32.

What is the fire-resistance rating for VELUX skylights?

VELUX skylights are fire rated for class B.

Where can I find the architectural drawings and specs for each VELUX product?

Over on our technical documents page! There you can find architectural drawings, commercial application drawings, and product specifications for each VELUX product.


Other Q's

How long does it take to receive an order from VELUX?

The majority of VELUX items ship within 24 hours so they arrive at your local dealer within 2-4 business days of your order. Some special order items may take longer, and any questions you have regarding a specific order can be answered by our customer support team at 1-800-888-3589.

What is the difference between a 5-star installer and a 3-star installer?

VELUX 5-star installers focus on installing only VELUX skylights or sun tunnels. On the other hand, 3-star installers are certified by VELUX to sell and install VELUX skylights and sun tunnels while also offering a wider range of roofing services.

Where can I find product testing, regulation codes, and certifications for each VELUX product?

Check out our Product Testing and Certification page for more information on product testing, regulation codes, and VELUX product certifications.


Got a question you don't see answered here? Check out our online help center to see if your question's been answered there, or reach out to our customer support team. We're always happy to help!