Adding Skylights to a Garage

Bring more natural light into your garage space with the addition of skylights. Skylights are an excellent way to brighten up a dark garage while also providing ventilation. Installing skylights in your garage can seem daunting, but it is an achievable DIY project if you have some basic construction skills. Here is an in-depth guide on everything you need to know about adding skylights to a garage.

Choosing the Right Skylights for Your Garage

When selecting skylights for a garage installation, there are a few key factors to consider:

Skylight Type

  • Fixed skylights – These do not open and are the most affordable and energy efficient option. Best for garages that already have sufficient ventilation from windows or doors.
  • Ventilating skylights – More expensive but allow fresh air in. The vent can be manually operated or solar powered. Ideal for stale, humid garages.
  • Tubular skylights – Bring in light through tubes from roof to ceiling. Great for garages withminimal roof space. Require less structural change.
  • Glass or plastic dome – Glass domes are more durable and provide clearer light. Plastic is cheaper but can discolor and warp over time. Glass is the better long-term investment.

Skylight Size

  • Measure the garage’s floor space and ceiling height. Skylights should equal roughly 5% of the total floor area.
  • Standard sizes are 2×4 feet or 2×6 feet. Custom sizes available too.
  • Consider multiple smaller skylights rather than one large one for better light distribution.

Energy Efficiency

  • Look for Energy Star rated skylights that meet strict energy efficiency guidelines.
  • Skylights with Low-E (low emissivity) glass help reduce heat loss and limit UV ray damage.
  • Some skylights come with insulating glass and gas fills like argon for improved insulation.
  • Consider solar or electrochromic tinting to reduce glare and heat during summer months.

Curb Type

  • Curb mounted skylights install on a raised framed base on the roof. Easier for new installs.
  • Deck mounted skylights sit flush with the roof. Required for replacement projects.

Wellsuited Brands

  • VELUX, FAKRO, and SunTunnel are some of the top skylight manufacturers.
  • Avoid cheap big box brands that tend to leak over time. Stick with reputable companies.

Preparing for Skylight Installation

Proper planning and preparation will ensure your skylight project goes smoothly. Here are some key steps to take before installation day:

Choose an Installer

  • Find an experienced professional skylight installer if you lack roofing expertise.
  • Get references and check reviews. Look for an established contractor who includes a warranty.
  • A poor installation job will result in leaks or other issues down the road.

Pick an Optimal Placement

  • The best place for a skylight is above an open area clear of obstructions.
  • Consider garage storage, electrical conduits, or pipes to avoid.
  • Central ceiling placement provides the most even light distribution.

Roof Analysis

  • Make sure the condition of the roof is suitable for skylight installation.
  • Repair existing leaks or damage first before cutting into the roof.
  • Inspect roof angles and elevation. Skylights require a minimum roof pitch of 3:12.

Moisture Protection

  • Use ice guard membrane for cold climates to prevent ice dam leaks.
  • Install peel-and-stick underlayment around the opening to provide a water-tight seal.


  • Building permits are usually required for skylight installs. Some homeowners choose to skip permitting but this risks fines if caught.

Order the Skylight

  • Measure carefully! Custom skylight sizes often take 4-6 weeks to arrive. Order early.
  • Have all materials and flashing ready for a smooth one-day installation.

Step-by-Step Skylight Installation Process

Once you’ve selected the right skylight and made preparations, it’s time for installation. Follow these key steps:

Mark the Opening Area

  • Outline the opening space for the skylight on the roof. Include an extra 6 inches on all sides.
  • Make sure the framing required will fit between roof rafters before cutting.

Create the Roof Opening

  • Using a circular saw, cut along the outline made in Step 1.
  • Make angled cuts if the skylight sits close to the roof edge.
  • Remove shingles and roof boards inside the outline.

Build the Skylight Curb

  • Construct a raised wooden frame (the curb) to fit the opening.
  • Use weather-treated lumber and attach securely to roof rafters.
  • Curb size should match skylight flange size.

Install Underlayment

  • Cover curb and opening with water-resistant roofing underlayment.
  • Use flashing sealant tape to seal corners and staple in place.

Install Flashing

  • Apply step flashing pieces in shingle pattern to sides of curb.
  • Add galvanized metal drip edge along front curb edge.
  • Cover top with L-shaped flashing along entire curb top.

Set and Seal the Skylight

  • Place skylight dome on curb and align flashing with flange.
  • Screw flange into curb through pre-drilled holes. Space evenly.
  • Caulk all edges with high quality polyurethane sealant.

Replace Shingles

  • Re-shingle around skylight curb using same shingles as roof.
  • Use flashing sealant on bottom row. Nail in place.
  • Seal all nail heads with silicone caulk.

Interior Finishing Touches

To complete your new skylight install:

  • Trim interior ceiling opening with wood frame to create a polished look.
  • Tape and mud seams between frame and drywall to blend. Sand smooth.
  • Paint interior frame to match ceiling color. White is ideal for maximum light reflectivity.
  • Consider wiring an electric light inside the curb to supplement when needed.

Skylight Maintenance Tips

  • Clean interior and exterior glass 2-4 times per year with a soft cloth and mild cleaner.
  • Caulk exterior sealants and flashing every 2-3 years to maintain water-tightness.
  • Check roofing shingles around curb regularly for damage or leaks.
  • Avoid walking on skylights to prevent cracking or loosening of seals.
  • Clear debris and leaves from exterior glass with a dry brush – don’t use a wet cloth which can stain.
  • Lubricate and adjust vent hardware annually to prevent sticking.
  • Verify screws are tight on vent models and re-tighten if loose.

Cost Factors of Adding Skylights to a Garage

  • Skylight unit cost – Fixed size averages $200-$1000 depending on glass type, venting, custom sizes can be $1500+.
  • Additional materials – Underlayment, flashing, lumber for the curb, sealant. About $50-$150 total.
  • Labor costs – If hiring a contractor, expect to pay $500-$2000 depending on the roof complexity, number of skylights, and location.
  • Permit fees – Building permits average $25-$100 but can cost more for extensive electrical or structural changes.

In total, plan on spending $1000-$3000 to add one or more basic skylights to an existing garage. Complex custom skylight projects with electrical components will cost more. But the benefits of increased light and ventilation in your garage space make skylights a worthwhile upgrade.

Skylight Alternatives for Garages

If skylights are not feasible for your garage, consider these alternate options to get more natural light:

  • Replace standard garage doors with insulated glass models to allow light through.
  • Add rectangular transom windows along top walls, protected from errant balls and sticks.
  • Install sun tubes or light tubes which route light in through ceilings via reflective tubing.
  • Replace exterior walls with glass garage doors or windows (great for hobby garages).
  • Paint interior walls and ceilings white to maximize light reflectivity.
  • Install extra electrical lighting on ceiling and walls to compensate for lack of natural light.

Frequently Asked Questions About Adding Skylights to a Garage

How much does it cost to put a skylight in a garage?

The total cost for installing one or more skylights in an existing garage averages $1000-$3000. This covers the skylight unit, flashing and waterproofing materials, roof and ceiling framing, labor, and permits. Higher end custom skylight projects can be upwards of $5000.

Can you install a skylight yourself?

With some DIY experience, you can install a skylight yourself. You’ll need to be comfortable framing the curb, flashing, roofing, and sealing. Most manufacturers provide detailed install guides. But for complex roofs or limited DIY skills, hiring a pro is recommended.

Do skylights leak?

When installed properly using flashing and sealants, skylights are no more prone to leaking than a regular roof. Cheap units and poor installation lead to leaks. Avoid this by purchasing quality skylights and ensuring they are correctly integrated into the roof structure.

How much natural light comes through a skylight?

Skylights can admit up to three times more natural light than a standard window during daytime hours. To maximize light, choose skylights with glass rather than plastic, opt for more small units versus one large one, and place near the roof ridge.

Should skylights be kept open or closed?

Venting skylights should be closed at night and during storms or high winds. They can be kept open on sunny, calm days to maximize ventilation. Make sure to have screens to prevent bugs and debris from entering the open skylight.

Do skylights reduce energy bills?

Skylights allow you to turn off artificial lights during daylight hours, reducing electricity usage. At night they do lose heat which must be counteracted. Opt for double-pane glass skylights to limit this heat transfer. Overall, skylights can moderately reduce energy costs.

Can you put a skylight in a flat roof?

Yes, curb-mounted skylights can be installed on flat or slightly sloped roofs by building up a raised frame. The curb should have a minimum 1/4 inch per foot slope to allow for proper drainage. The skylight dome is then mounted on top of the built up curb.

How difficult is it to install an electric skylight?

Hardwiring a skylight takes advanced electrical skills. First an outlet needs to be roughed into the attic and properly integrated into the existing circuitry. Running wires through the roof and waterproofing connections also poses challenges. Consider hiring an electrician for this complex task.

Do I need a permit for a skylight?

In most cases building permits are required when cutting into the roof structure for skylights. Some homeowners opt to skip permitting to save money but this may result in fines if caught. If doing major electrical work an additional electrical permit is usually also needed.

Should I get glass or plastic skylights?

Glass skylights are more durable, provide clearer lighting, maintain their appearance over time, and have better insulation against heat transfer. Plastic skylights are cheaper upfront but warp and discolor after a few years. Glass is the better long term investment for your garage skylight project.


Installing one or more skylights is an effective way to open up and brighten a dark, dreary garage interior. Although a challenging DIY project requiring roofing expertise, the benefits of increased natural light make garage skylights a worthy upgrade. With proper planning and careful installation, you can safely add skylights to your garage. Just be sure to choose the right skylight type and placement for your needs, make all necessary roof preparations, and install using best practices. Your garage will seem brighter and more inviting with the addition of natural sunlight from above.