Skylight Windows

Installation Guides

At Skylights1, our rooflights go beyond the ordinary. They combine beauty, energy efficiency, and innovation, making them some of the best on the market. Now, with our easy installation guides, you can set them up yourself, regardless of your opening’s size.

Say goodbye to complicated installations!

Our skylight installation guide provides clear and concise instructions to help you easily install our range of roof windows. From flat roof windows to pitched roof windows, our guides guide you step-by-step through the process, ensuring a hassle-free installation. Check our videos:


For Download:

Structural opening – provided By builder

Bear in mind our Skylights sizes are the sizes of the bottom (internal) glass panel. The top panel is stepped by 100mm on each side, and the overall externally visible size is 200mm bigger in both directions:

For example, only in this guide will we present installation sketches for a Skylight 600mm x 600 mm. For all other sizes, we provide installation sketches in the gallery of each size separately.

Double/Triple Glazed Skylight 600x600mm has the following sizes:

The upstand should protrude a minimum of 150mm above the roof level

A minimum pitch of 8-10 degrees relative to the horizon must be provided to avoid water pooling in the middle of the glass panel (for every metre of Skylight a 10cm fall is required). It is worth spending a few extra minutes before applying the silicone to run a water test to ensure the water is not pooling (even though you are installing glass it will still bend in the middle). The internal distance upstand to upstand needs to be 10mm bigger than the quoted skylight size (in our example: 610mm by 610mm).

Upstand opening should allow for 5mm tolerance on each side:

Skylight Support – provided By builder

Install the support in such a way that the top of support is as follows:

-Triple Glazed Skylight – 46mm below the top of upstand

The Skylight support is a 25x50mm (2”x1” ) timber:

Weather the upstand

Apply the roof covering material to cover the external face and top of the upstand. 

Make sure all surfaces where the silicone will be applied are clean of dirt, dust, moisture, etc.

  1. Apply the foam rope on top of the 2”x1” timber support to level off any discrepancies which will prevent any pressure and stop cracking on the bottom glass laminated pane. THE WARRANTY WILL BE VOID IF A FOAM ROPE IS NOT USED.
  2. Apply, generously, on top of the upstand weatherproof sealant, usually, 1 tube is enough for 6 linear metres.
  3. Lower the skylight with suction cups, and make sure you check the load on each cup.
  4. Apply waterproof sealant on the underside of the overhang and smooth it over once more to make sure it is watertight.

Once you finish weathering the upstand, you are ready to install the Skylight.

Video Presentation

Installation Guides



Easily complete your skylight installation with our range of high-quality skylight installation accessories.

Frequently Asked Questions

What guarantees and warranties do you offer?

We offer a 20 year seal warranty on all our skylights.

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What does the warranty cover?

Our warranty is CE certified and meets European standards. As long as you install your skylight unit as per our instructions, the warranty is valid for twenty years. This covers you for any defects or damages, and we offer an aftercare service.

How can I get a price?

All our Skylight prices are on our product page. Discounts may be given if an order is above £2/5000 given as a trade price. Please contact our Customer Support Team for more information if you wish to make a large order so we are able to give you a discount code.

Can I collect my Skylight in person?

Yes, you can! Once you have placed and paid for your order, please get in touch with our Customer Support Team who will arrange someone to prepare your order for collection.

May I calculate the delivery costs to my location?

Yes, you can, if you go through to checkout, it will work out the delivery costs and options without placing an order.

Do you do the installation as well?

No, we do not install. We only supply the skylights. We recommend looking for a reputable roofer within your area who can carry out the installation professionally.

Do your skylights open and close?

Yes, we offer fixed and openable skylights.

What is the max Ug-Value?

The maximum value our skylights has is 0.9 W/m²K

Can I have blinds on my Skylight?

Yes, you can have them installed once your skylight is fitted! As the installation of blinds behind the glazing increases the risk of Thermal Stress Glass Breakage, we advise you to install the blinds at a minimum distance of 150 mm from the glass.

Will it be noisy if it rains?

All our Skylights come triple-glazed which provides optimum sound insulation. This, in turn, would help minimise any rain noise. The more panes of glass, the better the noise resistance and the greater the distance between each glass, the better your sound insulation will be. All our skylights are designed with these factors in mind. We offer triple glazed skylights with 6mm toughened safety glass as standard and a generous 15mm gap between the panes and bottom. Panes are 8mm thick reducing noise to maximum.

Where are your skylights sourced from?

Our skylights are manufactured in Europe.

What makes us different from the rest of the market? guarantees in supplying top quality products at the Best Price, due to manufacturing and delivering everything in house.

What accessories will I need?

Do these come as standard or do I need to order them separately? You will need foam rope, weather proofing silicone and flashing kits along side your skylight. We have all of these on our website so you can order everything you need from us so you are ready to go.

Can I get next day delivery?

Yes, we offer express delivery to most postcodes. Please check this service on our website or give us a call.

How Can I Pay for my Skylight?

We accept PayPal, Credit and/or Debit Cards (Stripe), Google Pay, Amazon Pay and Direct Bank Transfer. You will see these payment methods offered to you upon check out. Unfortunately, we only accept payment in advance.

What pitch should my flat-roof skylight be?

It is important to have your skylight installed at a slight angle relative to the horizon to allow water to run off the glass and avoid pooling. We recommend setting the rooflight at an angle of 45°. It is worth it to spend a few extra minutes before applying the silicone to run a water test.

What is the lead time for items in stock?

Lead time depends on the size of the unit and the exact location in the UK, please add the item to your card and your delivery postcode and you will see all delivery options to your location-keep in mind that you will not be charged at this stage.

What is the maximum pitch for these skylights?

Minimum 6, maximum 45 degrees.

How do I place an order? Can i do it over the phone?

The website is the only place to place an order, and we don't take orders over the phone- but we are always contactable to answer any questions at any point.

Can I hold off on delivery if I’m not ready yet?

Yes, just let us know any instructions for delivery or delivery dates in the “notes” box during checkout.

Can I apply my own tint?

You can order a tint for your skylight by selecting the option on our custom calculator, we offer a green or blue tinted option.

Will the window need assembling upon arrival?

No, the skylights arrive ready to install (don’t forget to order your accessories separately so you can be ready to go).

Double or Triple Glazed?

Triple Glazed skylights tend to have a better U-Value and Noise Resistance. What this means is that a triple glazed skylight will have better noise reduction properties if you live in a noisy area. The lower U-Value benefit of them is that they have less heat loss. So if you plan on having a larger skylight or more than one skylight on your extension letting in more natural light we would recommend going for triple as it will save you on your energy bills and lose less heat.

Double Glazed Skylights tend to be lighter in weight and easier for installations however they are not as good on heat loss and noise reduction as triple.