How to Install Windows with Window Nailing Fins

Most new construction windows include nailing fins that secure the window to the wall sheathing and help create a weather-tight system. In this guide, our window experts walk through the installation process for Marvin windows with foldable nailing flanges, using a Marvin Elevate Double-Hung Window as an example.

Always check your window manufacturer's warranty information and weather-resistant barrier (WRB) details to make sure you are following installation practices that uphold the product warranties. In this guide, our window pros follow standard practices for applying windows with nailing flanges, using a Marvin Elevate Double-Hung Window with Dupont Weathermate Plus Housewrap as an example.

Step #1: Apply Manufacturer-Approved Sealant

Apply caulk ½” up and ¾” from the cornerApply caulk ½” up and ¾” from the corner

After you’ve prepped the window rough opening and you’re ready to place the new window, apply a bead of caulk around three sides of the opening — a half inch up, and ¾” inch from the corner.

Marvin-Approved Sealants

Marvin requires the caulk to be compliant with ASTM C920, Grade NS, Class 25. We recommend:

Also, if the sill pan is pitched at an angle, you’ll need to place shims along the sill to create an even plane.

Step #2: Place the Window and Secure the Nailing Fins

Use a fastener in every other hole (at a minimum)Use a fastener in every other hole (at a minimum)

Now you’re ready to place the window and secure the nailing fins. We recommend using 2-inch galvanized roof nails as your fasteners, placed (at a minimum) in every other hole. To achieve maximum ratings, place a nail in every hole.

As you secure the fins, check and recheck that the window continues to operate properly and that it remains centered, level, plumb, and square. A bent or angled nail can push or pull a window out of place.

Integral vs. Non-Integral Nailing Fins

Integral nailing fins are rigid flanges that are part of the window frame. These nailing fins are commonly found on vinyl windows.

Marvin products feature a foldable, non-integral nailing flange across most of its product lines. Marvin’s flexible nailing fins are less susceptible to damage than rigid vinyl nailing fins, both during and after installation, and can be pushed through the rough opening from the inside.

Step #3: Shim the Interior

Place shims and check for square and levelPlace shims and check for square and level

Once you’ve fastened the window flanges, place the interior shims — 4 inches from the top and bottom, 16 inches or less on center, and at each point of operation.

Before moving forward:

  • Check for square, measuring diagonally both directions
  • Check the sill for level
  • Check in 3 directions across the window to make sure it’s been shimmed correctly and nothing is bowed

Tip: Through-jamb installation is best practice for Marvin windows with and without nailing fins. Fold down the sashes of the window, identify the pre-drilled holes and use #8 x 3” screws to fasten through the jamb of the window. For more details, see the Elevate Through Jamb Installation Instructions from Marvin.

Step #4: Remove Packing Blocks and Check for Proper Operation

Make sure the window operates properly before flashing the exterior Make sure the window operates properly before flashing the exterior

Finally, remove the packing blocks and make sure every component of the window is operating correctly. After you check the window is operating properly, you can cut off any excess material of the shims to create a flush service to install drywall and trim. If everything is working smoothly, you’re ready to move on to flashing the window.

Step-By-Step Video Tutorials for Installing Marvin Windows

Watch our video tutorials on how to install a Marvin Elevate Double-Hung Window according to the manufacturer’s instructions — from prepping the window opening to flashing the exterior window. Our team covers best practices for installing new windows with a variety of weather-resistant barriers:

If you have any questions about working with these housewrap systems or installing Marvin windows, let us know! The Ring’s End window team will be happy to help.

Next: How to Flash a Window

After the new window is secured within the rough opening, you’ll need to flash the window to make sure no moisture can get in. Read the next article in the series:

Ring’s End is a Trusted Resource for Window Installers

As an experienced window supplier and installer, the window team at Ring’s End knows the importance of following proper install best practices!

Our window pros have been working with the Marvin brand for over 50 years, and we’re proud to be an authorized Marvin dealer due to the quality performance and design versatility of Marvin products. If you want to experience Marvin windows for yourself or talk with our window specialists in person, visit one of our eight showrooms across the Northeast. We offer a variety of complimentary services for window contractors and would love to be a resource for your business.

Consult with Our Architectural Services Team

Window Nailing Fin FAQs

What are nailing fins on a window?

Is a nailing flange necessary?

How do you install a window without nailing flanges?