installing flat rectangular skylights
Flat skylights installation is a relatively complex task, with particulars dependent on the roof type and skylight models. Hire a professional to get a proper installation, unless you are a skilled person engaged in a DIY solution.
Below we list the main steps associated with a basic installation of a flat self-flashed skylight. They are especially valid to the basic model of the largest world skylight manufacturer (Velux).
Those installation steps are valid for roofs with a pitch between 15-60° and asphalt shingles up to 5/16’’/8mm, and are a rather schematic approximation to a relatively complex process.
Installation steps for rectangular self-flashed skylights
1
The first step involves the cutting and framing of the skylight opening, which should have into account the skylight dimensions and the measurements indicated by the manufacturer.
As shown in the image, asphalt shingles are installed to bottom of the opening. Framing headers should be placed perpendicularly to skylight; you also should install a proper underlayment on the roof deck.
2
To align the skylight in the opening, install position blocks, and then tack the skylight with roofing nails. See image.
3
Each skylight bracket should be fixed to the roof with the nails provided by the manufacturer. Nails should penetrate the roof rafter or truss (typically through angled holes).
4
Install the shingles tightly against the sides of the skylight. Nail the shingles to the flexible flashing flange, to tightly secure the shingles. See image.
5
Notch the asphalt shingles around the head flashing, closely, without leaving gaps.
6
The head flashing should be overlapped with underlayment (to ensure proper drainage). Self-sealing rubberized asphalt-sheet and roofing paper about 8 inches wide are largely used on underlayment. Underlayment and flashing should be installed correctly to avoid leaks around the skylight. See image.
7
The final steps of the skylight installation involve installing and notching asphalt shingles close to the head flashing. The metal parts of the flashing should not be nailed. Before installing drywall or other tunnel finishing material, the installer should remove the positioning blocks used to ensure the skylight alignment.
Images credit: Velux America
See also:
Skylight Basics
Buying and Selecting skylights
Traditional rectangular Skylights
Modern Sun Tunnel Tubular Skylights
Skylights and Roof Windows
Venting vs. Fixed skylights
Plastic Skylights vs. Glass skylights
Rectangular Skylights flashing
Skylights, condensation and leak problems
Skylights Drawbacks
Shades, blinds and awnings for skylights
Types of skylight blinds and shades
Skylight Insect Screens
Sun Tunnel Tubular Skylight Installation
Roofs, ceilings and skylights
Skylight Location
Skylight Glasses
Skylights, Windows and Climates Zones
Skylights and rainy cold climates
Skylight Manufacturers