HOW TO INSTALL A SKYLIGHT – COMPREHENSIVE SKYLIGHT / ROOFLIGHT WINDOW INSTALLATION MANUAL

When it comes to enhancing natural light in a room, a roof-installed window, or skylight, offers an elegant solution. If you’re considering a skylight as part of your home improvement project, rest assured, it’s a fantastic decision.

The up-stand opening should allow for 5mm tolerances on each side to ensure smooth fitting of the bottom pane of the skylight into the space. For example, if your quoted skylight size is 300mm by 300mm, we recommend the opening to be 310mm by 310mm.

Please note that the top glass of our product extends by 100mm all around.

If the quoted size of the skylight is 300mm by 300mm, the top panel will measure 500mm by 500mm with the added extension.

The pitch should be maintained at a minimum of 6 degrees to prevent water from pooling in the middle of the glass.

Before sealing the product with silicone, we recommend testing water flow to ensure no pooling occurs.

Good quality timber upstands should extend 150mm above the roof level.

• Apply your roof covering material to the side of the upstand for weatherproofing. Once weathering of the up-stand is completed, you are ready to install the skylight.
• The upstand opening should allow for a 5mm tolerance on each side.
• We recommend using 25mm by 50mm (2” by 1”) timber for the skylight support shown in yellow on the diagram.
• Ensure all areas where silicone is applied are clean and dry.
• Apply foam rope on top of the supporting wood (25mm by 50mm); this is crucial to prevent pressure on the bottom glass pane.
• Use a good quality weatherproof sealant on top of the upstand.
• Position the skylight using suction cups.
• Apply weatherproof silicone on the underside of the overhang.

Please be aware that all roof lights are made to order, and sizes cannot be changed once the glass is cut or toughened. We recommend that installers review and understand the measurements and instructions before proceeding with an order.

 

INSTALLATION ON PITCHED TILED ROOF

• Our Skylights can be installed at a maximum pitch of 45 degrees.

Flashing Installation Guidance  

1. Preparing for Flashing Installation – Begin by readying your flashing kit for installation along the window sill. This serves as the primary defense against potential leaks. Ensure proper application of a strip of self-adhesive membrane on each side, cutting enough to fold over the edges of the skylight. The objective is to match the width of the skylight sill. Secure the sheathing on all sides using a roofing nailer.
2. Sealing the Edges – The sealing process continues. Cut strips of roofing paper or self-adhesive membrane to cover the flanges, extending a few inches beyond the edges. Start with the bottom flashing piece, followed by the sides and then the top. If necessary, lift roofing nails obstructing the process with a pry bar, taking care not to damage the shingles. The aim is to create an additional barrier against leaks, extending at least 6 inches from the skylight corner. This step is crucial before installing the sill and step flashing.
3. Installing Sill Flashing – Your skylight should include a piece of flashing for installation on the bottom sill. Once in place, secure each corner with a roofing nailer. Finally, install each roof shingle, ensuring coverage of the sill flashing. Note that this is only installed at the bottom of the skylight.
4. Proceed to Step Flashing – Begin by equipping each side with step flashing, typically starting from the bottom and working upward. Position the L-shaped step flashing piece at the bottom, securing it with nails and covering it with a shingle. Continue installing step flashing on each side, overlapping the top half by a few inches and placing the next shingle piece accordingly. Repeat this process on each side until reaching the top corners.
5. Counterflashing – Ensure that the counterflashing fits snugly over the installed step flashing. This step is crucial to prevent snow and rain from penetrating under the roof window’s edge. It should either surround or be placed on each side of the skylight.
6. Saddle Flashing – Similar to sill flashing, saddle flashing is installed on the top part. Slide it into place under the shingles, secure it with roofing nails, and then reinstall the top half of the shingles as before.
7. Final Checks – With the shingles, flashing, and fixed skylights in place, perform a thorough inspection from the inside. If your skylight is operable, test it to ensure smooth functionality.

While these steps may appear straightforward, it’s advisable to seek assistance from professional skylight installers, especially for those lacking expertise in the matter.

Common challanges in skylight installation include:

• Installing Skylights to a Truss-Framed Roof: While it’s feasible to install skylights on a truss-framed roof, the space between the beams of each truss may limit the size of the skylights you can use.

• Installing Skylights in an Attic: When installing skylights in a room with an attic above it, constructing a light shaft can channel the light from the skylight to the room below. Optimizing light transmission involves flaring the shaft on all four sides.

• Installation on a Metal Roof: For corrugated metal roofs, positioning the skylight below the roofing lap and aligning it with the grooves on the fins is crucial for proper installation.

• Becoming a Heat Trap: In regions with intense sunlight, skylights can sometimes trap heat indoors on hot days. Installing shades or blinds can mitigate this issue. Alternatively, opting for ventilating skylights allows hot air to escape, helping to regulate indoor temperatures.

 

Frequently Asked Questions about Rooflight Installation

Do all skylights eventually develop leaks?

Leaking skylights were once a common issue, but modern designs incorporate improved sill flashing, greatly reducing the risk of leaks. When installed correctly, saddle flashing provides a high level of protection against water infiltration.

For instance, when working with roof rafters, it’s advisable to double them on the sides and affix a double-headed sill to the top and bottom sections of the opening.

How do you install a skylight on a flat roof?

Skylights can be installed on flat roofs without the need for a slope. Installers should focus on constructing the curb with a slight angle to facilitate water runoff to the sides. Curved glass skylights are also suitable for flat roofs.

What’s the process for installing a skylight on a tile roof?

Curb-mounted skylights are typically the preferred option for tiled roofs. Before installing the skylight, contractors will construct a curb around the roof opening and integrate the flashing into the shingles.