Window extensions

Home Improvement Ideas- Domed Skylights

sterlingbuild domed skylights on roof

By now, most of us will be familiar with the benefits that installing a rooflight can bring. A permanent and sustainable source of natural daylight that can brighten and freshen up any flat-roofed room, rooflights are well known for the savings they can provide homes and businesses with through their lighting and insulative qualities.

Rooflights, or skylights as they are also known, are also rightly regarded as an attractive interior feature that enable homeowners to open up the roof to the outside world, adding personality and value to their property in the process.

As much as the advantages of rooflights are easy to identify, choosing the right design can be a lot harder. Some flat roof windows are manufactured specifically with homes in mind, while others have been designed to accommodate commercial buildings. There are, however, versatile rooflights that are made for both. Domed rooflights are a prime example. 

Made with an exterior polycarbonate dome cover, with or without a glazed unit underneath, domed skylights represent a cost effective daylight solution for both domestic and industrial applications.

In this blog, we will look at the possibilities on offer with domed skylights by exploring the benefits relating to insulation and operation, along with design options. Let's start though by covering what will always be an important factor for all- costs.

Domed Rooflights Cost

open domed rooflight

Polycarbonate roof domes are one of most affordable rooflights on the market for residential and commercial builds alike. Made from thermoformed polycarbonate, plastic skylight domes are significantly cheaper than domes with double glazed units, despite offering many of the same qualities. 

Polycarbonate as a material is 250 times stronger than glass and is virtually unbreakable, meaning your roof dome will not break should it suffer a freak external impact.

This combination of low price and durability is what makes polycarbonate roof domes so popular a rooflight choice for buildings and offices where larger roof surface areas require investment in a greater number of rooflights.

Polycarbonate domes often come equipped with an upstand. This can save money (and time) on sourcing and building your own external kerb. This is the case at Sterlingbuild where the majority of our own range of polycarbonate roof domes, and our flat glass domed rooflights too, come with an upstand, ready for quick installation. Domes can be purchased on their own should you only require a skylight dome replacement and not the upstand. 

The extra cost of flat glass roof domes compared to polycarbonate domes lay chiefly with the fact that you are getting a double-glazed unit in addition to the polycarbonate dome cover.

Many find the interior glass finish a lot more pleasing on the eye, while the additional protection it offers from the weather is undeniable (more of which later). 

Our double glazed FAKRO and VELUX domes are some of the most stylish and contemporary roof domes available right now. If purchasing with Sterlingbuild, we can guarantee to beat the price of your domed skylight should you find it available for cheaper elsewhere. 

Shop Polycarbonate Domed Rooflights  Shop Flat Glass Domed Rooflights

Energy Efficiency in Flat Roof Domes

domed rooflights external view

It is up to you how energy efficient you want your domed rooflight to be. If you just looking to bring a splash of natural daylight to a small space, such as a storage room or garden shed, single skin domes will do the job. Naturally, this is the cheapest option as the domes are only suitable for uninhabited spaces.

The thicker the polycarbonate on the domes, the more thermally efficient your window and home will be. Double skin domes are recommended for skylight dome replacements, while triple skin is compulsory on new builds to comply with Building Regulations. 

With impressively low U-values of 1.24W/m2K, Sterlingbuild’s own range of quadruple skin domes offer the best thermal performance on polycarbonate domes and will go a long way in keeping your home warm during the colder months, helping you save on heating bills.

internal view of velux flat glass domed rooflights

Flat glass domed rooflights carry some of the lowest, and therefore best, U-values on the market. U-values are a great indicator of how energy efficient a window is, how well they regulate indoor temperature and how far they can go to help lower bills.

All VELUX and FAKRO doubled glazed domes have low values of 1.2W/m2K, while the best value on a double glazed dome can be found on Sterlingbuild’s flat glass, triple skined domed rooflight (0.72 W/m²K).

For the ultimate experience in energy efficiency, FAKRO’s quadruple glazed domes offer the optimum thermal and sound insulation, evidenced by the crazily low U-value of 0.72W/m2K

It is these money saving thermal qualities that make glass domes more expensive than their completely plastic counterparts.

Domed Skylight Sizes and Shapes

rectangular domed rooflightcircular domed rooflightsquare domed rooflight

Few skylights offer as much design choice than polycarbonate domed skylights. Polycarbonate domes are thermoformed to produce a number of different shapes, including popular circular, pyramid, rectangular, square and trapezoid styles.

Typically, these shapes come in a large selection of sizes, starting from 40x40cm going up to 180x180cm with Sterlingbuild. We offer a made to measure service on polycarbonate domes should the dimensions you need be missing among are standard sizes.

For help with measuring for flat roof domes, visit our 'How to Measure' blog

Along with shape and size, glazing and operation can also be customised when ordering a bespoke polycarbonate dome. If you are looking to let in as much sunlight as possible and keep views as translucent as can be, clear glazing makes the most sense. Opaque glazing is better for reducing the glare from the sun and providing a greater level of privacy.

Similar to polycarbonate domes, the size range of our glass domes ranges from 40x70cm to 160x160cm. 

Operating Domed Skylights

electric domed skylight

Polycarbonate domes and flat glass roof domes come in three operational styles; fixed, manual and electric.

Fixed domed skylights are best suited for rooms with sufficient ventilation already in place. Remember fresh air is even more important that light transmission and is the most important thing to consider.

If your domed skylight or skylights are to be the sole source of air flow, manual or electric options are most sensible. Manual domes can be installed out of reach and opened with a rod. Some manual and electric domed rooflights are also suitable as means of escape windows to comply with emergency exit requirements and should you require regular access to the roof. 

With electric windows, you can opt for a dome that opens via a wall switch, or for even more comfort and the luxury of opening your domed rooflight without having to move an inch, choose a remote controlled dome.

Sterlingbuild and VELUX have special smoke ventilation domes available that open automatically when smoke is detected to allow smoke and heat to escape the building in cases of fire. This makes them a smart choice for commercial properties with large kitchens.