DIY 101: How to Install a Skylight in Your Home

If you’re looking to brighten up a room in your home, then installing a skylight could be just the thing to do. You’ll be surprised how much nicer a room looks after it’s been given a healthy dose of natural sunlight – and a skylight lets in a lot more light than vertical windows. If you’ve been thinking of installing a skylight in a property you own, then you’ve come to the right place, as we have a handy guide for you.


Any DIY project is going to require some degree of planning. Here are a few things you first need to consider before you can get started:

  • You need to make sure that you are actually allowed to do this. You may need to apply for planning permission before you undertake a task like this
  • Remember that a skylight could become a heat trap in the summer. Make sure you take steps to prepare for the higher temperatures during those months
  • If you have an attic above you, you will first need to install a light shaft

Once all of these things have been taken into consideration, it will be time to buy those building supplies!

Essential supplies

To build a skylight, you will need:

  • Two by fours for the frame
  • Drywall
  • Roofing paper
  • Roofing nails
  • 16d galvanised nails
  • Step flashing
  • Continuous flashing

Instead of glass, we recommend using clear polycarbonate sheet. The reason for this is that polycarbonate is over two hundred times stronger than glass, but it’s also half as heavy. This is definitely an important factor when you consider that this will be going on the ceiling! Once you’ve got hold of these materials, you’ll be ready to start.

Step 1: Make the opening

This is a particularly tricky task. First of all, you will need to drill a locator hole in the ceiling – this will mark the centre of the skylight. Once you’ve made the hole, go onto the roof and and start cutting away the opening for the skylight with a circular saw. Cut the size as per the exact measurements that you’re using. Importantly, you need to make sure that you remove the rafters from the roof – trying to cut through them will make this job needlessly destructive! Obviously, make sure that you take proper safety procedures before doing this. Consult a professional if you are inexperienced with this kind of work.

Step 2: Cut back the roofing & set the skylight in place

Once you’ve made the opening in the roof, you will need to cut back on the roofing that surrounds the edges. Set the skylight in place above it using nails and screws. Importantly, you must keep in mind that you’re not yet properly fitting the skylight, just putting it in place.

Stage 3: Add the underlayment

This is where you’ll need your roofing paper. Cut off some strips (roughly 8 inches wide) and then slip them under the shingles. The reason you’re doing this is to ensure that water sheds properly. You will need to apply a layer on the top, bottom and both sides of the skylight. Lifting the shingles to slip the roofing paper under them can be quite difficult – you may need to use a flat pry bar to lift the nails.

Stage 4: The bottom & step flashing

Now it’s time to install the bottom flashing. This is a single piece that wraps around the skylight and sits on top of the roof shingles. You should drive roofing and/or bottom flashing horizontally into the skylight and not vertically into the roof. Once you’ve done this, you need to slip individual pieces of step flashing under the shingles. Start at the bottom of each side and work your way up. The step flashing pieces must overlap with each other by approximately four inches. You must also ensure that the flashing pieces are attached to the skylight and not to the roof.

Stage 5: Install the solid flashing pieces

These are very important because they are what stops water from leaking into your house through the step flashing and the skylight. You will then finally be able to install the top piece (aka head flashing) by sliding it under the roofing and attaching it to the skylight. And then viola! It is complete.

If this project is for a property you’re going to rent out, this could be a great investment. Just be sure that you know when to stop investing. A room with more light in it looks more attractive and appealing, so you can see why a skylight might be a good addition to any room. Just be sure that you have the capabilities to do this job, because if it goes wrong, it could be hard to rectify. You can always consult a professional if you still want to get the skylight installed. What jobs have you carried out successfully on your properties before?