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How to install a skylight

A skylight diffuser template being used to mark a hole in the ceiling to be cut to make way for Mylar tubing to come in from above

Overview

Installing a skylight is easy to do and an environmentally friendly way of bringing light into your home. You can improve the look and feel of any room, help cut your power bill and create an open feel in a closed space.

Steps

1Choose a location on your roof for the skylight.

Choose where you'd like to put the skylight on your roof.  Make sure it's where it gets the most sun but because the Mylar tubing is long, it gives you the flexibility to choose which room your internal skylight will be in.
A skylight template and flashing laid out on a roof for positioning purposes

2Preparing to install the skylight dome.

Place the skylight dome where you want it and work out how many tiles you need to remove. After removing the tiles, place the dome on your chosen spot and outline it, to mark the tiles that need cutting. 

Tiles being removed from a roof to make way for a new skylight

3Cut the tile batten and surrounding tiles.

You might also need to cut the batten so the dome sits flush to the roof. Mark where the batten needs cutting and use your handsaw to cut it. Wearing your safety glasses and earmuffs, cut the tiles to shape using a grinder with a diamond blade. Put the tiles you've cut back in place and put the dome over them, you may need to cut some surrounding tiles so the dome fits properly.
A tile batten being sawed through by a Bunnings team member standing on the roof

4Installing the Mylar Tube and Dome.

Before installing the dome pull the Mylar tube over the back of it and use the silver tape to secure it.  Put the side marked ‘top' closest to the top of the roof. Feed the Mylar tube into the roof space and put the skylight dome in place by tucking it under the surrounding tiles.

A Mylar tube being fitted to a sheet of tin flashing by a Bunnings team member on a roof

5Make sure the dome is waterproof using silicone

Use silicone to waterproof under the side of the dome. Make sure you apply a fair amount of silicone under to prevent any leaks in the future. Now use a hammer to gently shape the flashing around the dome to match the roof's profile. Then apply more silicone around the flashing to seal it.

Silicone gap filler being used to waterproof the skylight flashing's edge with the roof tiles below

6Mark up where you want to install the diffuser

Before you can cut a hole in the ceiling, you need to know where the joists are. You can use a stud finder for this. The ideal place for the skylight diffuser is between these joists. Once you have selected your position, measure across the width of the ceiling and mark out a centre line.

A Bunnings team member marking out the position of a skylight onto the ceiling with a tape measure and pencil

7Cut a hole in the ceiling for the skylight diffuser.

Use the diffuser as a template to mark out where you want the skylight to be. Then using your plaster saw, cut out the hole. Next, pull the Mylar tubing from the roof space, through the hole. Make sure it's the right length. You may need to trim it if necessary.

A skylight diffuser template being used to mark a hole in the ceiling to be cut to make way for Mylar tubing to come in from above

8Screw the diffuser template into place

Fit the diffuser into the hole, using a drill to fix it into the ceiling. Screw it all the way through, but you need to secure it into the plaster using the plastic tabs over the top of the screws. Tighten the screws further for a nice firm fit, then insert the screw caps.

A skylight diffuser template being screwed into the ceiling by a Bunnings team member with a power drill

9Secure the tubing and install the diffuser

Pull the Mylar tubing down to the edge of the inside of the template. Now secure it in place using the silver tape. Run the tape around the inside edge of the template. Finally to install the diffuser, carefully bend it and fit inside the template.
A skylight diffuser being fitted to the inside of the diffuser template to finish the skylight

Suggested products

Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.