6-Step Beginner's Guide to Roof Windows

Simplify your journey to finding the right roof window by following our 6-step guide covering projects, quantity, spec, regulations and budget.

What's Your Project?

What is your roof window for? A loft or an extension? Roof windows can be either pitched or flat. With lofts, the main choice is between top hung pitched roof windows (unobstructed views, no head restrictions) and centre pivot pitched roof windows (adds daylight, less expensive).

With ground floor extensions, the roof can be either pitched or flat. If the roof is pitched, centre pivot roof windows are the more obvious choice as views are far less of a concern.

For flat roof extensions, popular window choices include flat glass rooflights and eye-catching roof lanterns. Regardless of design, all flat roof windows require an upstand (typically made of timber) to sit between window and roof to aid rainwater runoff. Some brands include the upstand with the window, others require the kerb to be built on site.

Pitched roof windows also need to be watertight and therefore require a compatible flashing to be purchased as a necessity.

What's Important to You?

Other key specifications that needs considering include operation, glazing and frame material.

Pitched roof windows can be manual, electric/solar or fixed. Electric windows can be operated via remote control, mobile phone and even automatically. Naturally, manual and fixed windows are lower in price.

In extensions, it is common for the flat roof window or lantern to be fixed as ventilation is usually already provided by the vertical glazing, i.e, from bifold doors. Manual and electric options are available.

There are four main types of frame. A natural lacquered pine look, white-painted pine, PVC and polyurethane. The latter two moisture-resistant finishes are the ideal solution for bathrooms and kitchens.

Special glazing options include enhanced noise reduction, insulation and privacy. A window's U-value is its thermal efficiency. The lower the value, the better the window at trapping heat inside a room.

How Many Windows do You Need?

You can never really have too much daylight in your home. It will always make the space lighter and brighter. 

However, we do recommend that the amount of glazing area you have in a room should account for a minimum of 15-20% of the overall floor area. This applies to both lofts and extensions.

Roof windows can bring in twice as much daylight as vertical windows of the same size, allowing light to penetrate deeper into the home.

If your extension is north facing, roof windows are even more important to the daylight levels in a space. In some case it is the only way to get sunlight shining directly into the room.

Of course, budget will often dictate how many roof windows you’re able to afford. Talking of the purse strings…

What Can I Get For My Budget?

You do not have to blow the whole of your budget to get enough daylight from your windows.

RoofLITE and ECO+ are brands that offer outstanding value for money through a diverse range of pitched roof windows (RoofLITE) and flat rooflights (ECO+) compared to some better-known brands.

Another way to save money is to order from stock, provided that the size you require is listed on our website.

If your size or desired spec is not available, many of our pitched and flat roof windows can be made bespoke to non-standard sizes in a variety of different RAL colour and glazing types.

When money is less of an issue, make a statement in your extension with a roof lantern or a VELUX CABRIO balcony system in your loft.

Know Your Rules & Regs

Installing roof windows into a loft usually falls within Permitted Development Rights (PD), however there can be limitations as to what your roof window can look like and where it can be installed. Complete guidance on PD and Planning Permission can be found on the Planning Portal.

We always advise you talk to your local planning authority before you invest time and money into renovations, particularly if your property is located in a conservation area or area of outstanding natural beauty.

In conservation, specialist conservation windows (pictured) are required.

Depending on what fire escape routes already exist in your loft, you may need a top hung window if it is deemed the only means of escape. We include a 'suitable for escape' specification on all of our pitched roof windows.

What Extras Do You Need?

Once your windows are sorted, you might want to think about any extras you need.

Most brands of pitched roof window have installation products available to optimise the watertightness and insulation efficiency of the window.

Blinds can be an essential extra depending on how a window is used. Roof window blinds come in a plethora of colours and designs for both pitched and flat roof units.

Other accessories to consider include control rods to open high level windows and maintenance kits to keep the windows looking as good as new.

Although not a roof window extra, sun tunnels are a daylighting solution alternative that are perfect for windowless rooms and darker areas.