Sunsquare: The market leaders in skylight and roof light design and installation


The internet is full of complaints from owners of skylights – not purchased from Sunsquare – about the levels of condensation created on the glass surface, resulting in excess moisture in their living environment.

Skylight condensation occurs most frequently when warm, moist air rises to the ceiling and comes into contact with the colder glass surface that’s influenced by outside temperatures and weather conditions.

It’s the conversion of vapour into liquid, which occurs when the air becomes saturated with moisture and releases it in the form of water droplets. The condensation can be identified by the mist-like conditions that can appear and cloud the interior glass of your roof window.

There’s also a danger that skylight condensation can form on more than just the glass pane. In some cases, poorly installed rooflights neglect the use of roofing felt and insulation between the frame of the unit and the rough opening of the roof. Thus encouraging warm, moist air to leak out from interiors below and come into contact with the underside of the flashing or cladding.

The outcome is that the additional condensation can then drip downwards back into your interior below in the gap between the frame and rough opening. As a consequence, this is often confused as a leak but is simply due to the lack of felt and insulation between the frame and rough opening.

Common causes of excess moisture in the home

We contribute more water vapour (humidity) to our internal atmosphere simply by doing the following things, resulting in excess moisture and contributing to the condensation on windows and skylights:

  • Everyday breathing
  • Human perspiration

  • Cooking

  • Cleaning

  • Showering

The above factors can cause air to become saturated, dispelling the moisture by condensing it straight back into water, which shows up on your glass panes.

Signs of condensation to look out for

It is very easy to spot the warning signs of condensation within your home:

  • Peeling or bubbling wall paint

  • Mould or mildew on walls, window seals and baseboards

  • Worsening wall and attic insulation

  • Deteriorating floor tiles and furniture

  • Structural integrity of wood between outside walls beginning to rot

How to improve ventilation in your home

By allowing moist internal air to escape outside you’ll need to encourage dry outdoor air to come in to replace it. Here are some of the simple steps you can take to better ventilate your home and reduce the possibility of condensation on your skylights and windows:

  • Use internal exhaust fans more frequently to expel hot moist air outside.

  • Open windows in living areas each day for better air circulation.

  • Keep window blinds and shades open to encourage warm air to circulate around your windows.

  • Ensure tumble dryers and gas appliances adequately vent moist warm air outside.

But there’s an even easier way to avoid skylight condensation...

Purchase a flat roof skylight that’s BSI Kitemarked for weather tightness, wind loading and – more pertinently for this particular article – air permeability. The only place to get a BSI Kitemarked flat roof window in the UK is right here at Sunsquare.

Every single skylight that we design, manufacture and install for our clients is thermally broken using multiple polyamide insulating sectors. No comparable flat rooflight on the market is capable of keeping the interior glass pane warmer. Our optional Sunsquare upstands are regularly purchased by our clients to ensure that their skylight fits and fits well into the roof membrane.

Not only does a Sunsquare upstand make the skylight installation process supremely straightforward, it also offers excellent energy performance and 0% condensation risk. Constructed from a unique sandwich panel using highly sophisticated insulating foam, our upstands have been tested to cope with the most demanding weather scenarios.

Some of our skylights can provide simultaneous natural light and ventilation into your home too. Our Aero Electric range can be operated using a handset, opening your rooflight either for ventilation or roof access, thus improving internal air circulation and minimising condensation risk.

At Sunsquare we have been innovating the UK skylight industry since 2004 with bespoke, pioneering designs that not only provide a stunning architectural statement but break the mould for safety standards.

If you’re looking to transform your roof with abundant natural light it doesn’t pay to scrimp on a cheap product that could cost hundreds if not thousands of pounds’ worth of damage if it was to fail.

Believe in better and let us advise you on the best possible skylight solution for your project. Contact our senior sales team today for friendly, experienced guidance.

Image: Gabriel Flores Romero

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