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A guide to skylight installation for residential and commercial projects

10 June 2019
Whether you’re a homeowner or a business, a professional skylight installation is vital to ensuring the long-term performance of your roof windows. Learn more.

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A guide to skylight installation for residential and commercial projects

Every property’s needs are different when it comes to flat roof skylights. Whether you’re a homeowner looking to encourage abundant levels of natural daylight or ventilation into living areas or basements or business looking to improve the working environment of offices and communal areas, a professional installation is vital to ensuring the long-term performance of your roof windows and maximising your investment.

If you’re thinking of undertaking a skylight installation yourself as a self-builder, or you’re just curious how the professionals undertake the process, this article will equip you with all you need to know about fitting a flat roof window to your residential or commercial property.

Things to consider when fitting a skylight

Here are some of the frequently asked questions that we get from prospective clients looking to buy and install their first flat roof skylight:

How much does it cost to install a skylight?

In the case of a standard 2ft x 4ft skylight:

  • Cutting the roof opening and altering the rafter framing = Approx. £150-160
  • Installing and flashing the skylight = Approx. £150-£250 (up to 30% more for metal or tiled roofs)
  • Create a chase from the skylight to the interior ceiling = £800-£1,200
  • Redecoration of the ceiling beneath your new skylight = £200 (more for open-plan spaces)

How much value will a skylight add to my home?

While there is no definitive price difference between a home without a skylight and a home with skylights, those with skylights installed are more likely to appear spacious and welcoming thanks to the increased levels of natural light.

Even modest living rooms and dining areas can feel bigger thanks to the influx of natural daylight from above, which can help homeowners to achieve sale prices at the higher end of their property’s overall value.

Do I need planning permission for a roof window installation?

In England and Wales, you do not normally need to apply for planning permission for the insertion of new roof windows subject to the current limits and conditions stipulated by the government’s Planning Portal under Schedule 2, Article 3, part 1, class C permitted development.

This includes:

  • Any alteration cannot project more than 150 millimetres from the existing roof plane i.e. any new flat roof skylights cannot project more than 150 millimetres.
  • No alteration can be greater than the highest part of the existing roof.
  • Side-facing windows must be obscure glazed with any opening to be made 1.7 metres above the floor.

What is the average skylight replacement cost?

At Sunsquare, our stock-size standard fixed rooflights are available in our online shop from £775 plus VAT. These are our cheapest flat roof skylights and can be delivered to your address from our headquarters in Bury St. Edmunds, Suffolk within five working days.

What is the life span of a roof light installation?

You can get a good gauge for how long a roof light installation should last by looking at Sunsquare’s warranty period.

How much value will a sky light add to my home?

We offer a comprehensive 10-year warranty for our entire range of skylights, covering all items supplied, except motorised/electrical components which have their own separate two-year warranty.

The insulated glass units within our skylights are also supplied with a 25-year unit seal guarantee, so you can be sure of the performance of your skylight glass for at least a generation.

The basics behind how to fit a skylight

  • Cut and frame your roof opening. Following your skylight manufacturer’s specifications, cut the frame of your roof opening. Drill a central hole where the rooflight will be and begin by cutting the opening with a circular saw. Ensure all of the ends of roof rafters are supported before cutting them by fitting header joists perpendicular to the other joists.
  • Cut back the roofing, removing enough tiles or slates from the area, and set the skylight in place Using a Stanley knife and a straight edge, cut back the roof shingles some three inches from the opening on all sides of your new skylight. Position the skylight centred on the opening and fasten with screws or nails.
  • Underlay roofing paper Position the underlay of roofing paper strips so that water will adequately escape from the base of the skylight.
  • Fit the bottom flashing Install a single piece of bottom flashing around the base of the skylight and the top of the roof shingles.
  • Slide step flashing under the roof shingles Fit single pieces of step flashing underneath the roof shingles from the bottom up, ensuring each piece is overlapped by at least four inches. Fasten the flashing to the skylight not the roof itself.
  • Fit the solid flashing Install the solid flashing to the skylight framework, preventing water from reaching between the step flashing and the skylight

How do Sunsquare install roof windows?

If you lack the confidence or expertise to undertake the installation yourself, most skylight manufacturers will offer their own professional skylight installation service. At Sunsquare we have our own in-house installation team that can transport your rooflights to your property and oversee their installation in their entirety.

Note: This isn’t always the case with some skylight manufacturers that offer a so-called “complete” installation package which don’t include the necessary off-loading and lifting of your rooflight to the roof surface.

One of the most critical factors during any roof window installation is getting the sequence of events right. An upstand is the first thing that needs to be installed into your roof before anything else. Sunsquare supplies its own upstands to customers seven working days before the delivery of their skylight.

Upstands are frames upon which the roofing membrane is attached, and the skylight sits on top. They ensure the correct pitch to allow for water run-off.

Although it’s possible to get a roofer to create a cheaper upstand for you, a Sunsquare upstand guarantees the correct fall and size and the perfect fit, without any expensive roof adjustments.

Note: There are some manufacturers that supply integral upstands with their products. While this might sound beneficial, it’s actually not. If the skylight should fail or require maintenance, the entire roof around the skylight must be removed, which is long-winded and expensive. An external upstand is definitely the way to go.

Why choose Sunsquare for your installation?

You can rely on our installation team to provide a professional service when fitting a skylight into your property. Our installers must have a minimum of two years’ experience manufacturing in our factories to be eligible to work on our installations. Our team has also been trained and accredited to the following standards:

  • CSCS Construction Skills – Health and Safety for Operatives
  • IPAF – Safe Use of Harnesses
  • ATUK – Working at Height

Our installers will arrive in a safe, professional uniform and the equipment that enables them to deal with any situation on-site. We often employ our own crane to lift skylights to roof surfaces. For more complex installations, our team may also undertake a site survey before the day of installation, which is covered in the skylight installation costs.

We also include bedding tape free of charge to seal all of our skylights to our external upstands. This means that no sealant is ever needed, with strips of double-sided tape stuck to the top of the upstand and the skylight placed carefully on top, creating the perfect seal for thermal and waterproofing properties.

As you can see, our commitment to quality doesn’t end when our skylights leave our factory. Our installation team are always on hand to provide installation and maintenance in a courteous, efficient manner.

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