Part 5 - Roof Windows

Adding a roof window can make the difference between a loft space that is usable and one that isn't.  This is for a number of reasons including the obvious €“ the lighting level and the not so obvious €“ fire safety regulations.

Here is a look at some of the most popular types.

Brands

Velux are the most well known brand of roof windows in the UK and are made by VKR Holdings.  The brand is constantly seeking update with this year seeing the launch of the New Generation windows that have great energy efficiency as well as allowing in the maximum amount of daylight.  They have the thin frames and larger glazed areas of other brands but add to this the developments they are known for.  These include electric options such as Bluetooth controllers and rain sensors and the roof terrace system to create an instant balcony.

The Duratech windows are produced by the same company who make the more famous Velux windows and are known for their quality as well as attention to detail of their products.  These windows come with a 10-year guarantee and are lower in price than the Velux versions.  The windows feature slim frames that allow the most light into the room and have argon-filled double-glazing to give excellent thermal transmittance.  These windows are available with plain or contoured tile flashings, slate or universal in their material compatibility and also for either single windows or combinations.

Fakro are a brand of windows that started out in Poland in 1991 and has seen a huge growth since.  It is now the world's second largest roof window producer and have a comprehensive range including popular models such as centre pivot and top hung as well as unique variations of their own.

Types of window

The most frequently used type of roof window is the centre pivot style.  This has the handle positioned to the bottom of the window so it can be easily opened, even when positioned higher on the roof and also minimalizes the intrusion into the room.  These are suitable on pitches roofs from 15 to 90 degrees and come in finishes such as natural pine, white acrylic or lacquered.  The outer pane of glass is toughened to ensure that storm debris doesn't cause damage and, in the Duratech range for example, the space between the panes is argon filled for noise reduction.

Top hung windows are the ones needed for emergency exit purposes so they pivot either at the top or at the three quarter position on their frame.  Brands such as Duratech use gas springs to ensure the window opens smoothly and uses a trickle vent so that there is ventilation even when the window is securely closed.  These are also suitable for pitched roofs from 15 to 90 degrees and have storm toughened glazing.

For pitched roof areas that are over a bathroom, kitchen or other high condensation area, white uPVC roof windows are perfect.  They use a strong steel core to ensure low maintenance and aren't affected by steam or smoke as well as condensation.  They can work on roofs from 15 to 90 degree pitch and have a wipe clean polyurethane coating.

If you live in one of the 8000 or more conservation areas across the country where specialist planning permission is required for roof windows amongst other alterations, a conservation roof window is necessary.  Duratech's example is a centre pivot window with the external profile painted black and with a glazing bar down the centre of the external pane to comply with regulation.  These can be used on roofs with 15 to 90 degree pitches and have a storm toughened outer coating on the glazing.

Flat roof windows

Flat roof windows are understandably different to pitch roof windows because there is no degree of pitch involved.  There are two main options for flat roofs requiring additional light €“ skylights and roof domes.

The skylight can be used on a pitched roof but is perfect for flat roof and comes in fixed, opening and automatic options.  Roof domes are made from the same plastic as riot shields so can withstand almost anything thrown at them and also come in single, double or even triple glazing for additional security and heat loss prevention.

Fitting a window

Each brand of window will have its own coordinating accessories and it is important to use them to get the maximum benefit from your roof window.  The first step to fitting the window is one you may have already done if you are laying the whole roof €“ checking the pitch of the roof.  This is because certain windows only work on certain angles.  There are manual ways to work this out, online tables or even, depending on your phone, an app for it!

Once you know that the pitch of your roof and your favoured window match up, you are ready for the fitting.  Firstly, make sure there are no obstructions in the area you are going to place the window such as central heating vents, valleys or even the ridge line.  Next, if your window fits between the rafters on your roof, then great but otherwise you may need to add some framework to accommodate the window.  It is possible to cut into roof timbers to place a window if necessary but if possible, is best to avoid this as it can weaken the overall strength of the roof.  Seek out a planning officer if you need to cut the rafters to ensure roof safety.

The underlay needs either to be cut on an existing roof or laid to the point of the window on a new roof.  Any joints will need to be sealed with black Butyl being one of the more popular methods for doing this.  A similar job needs to be done with the underfelt on the roof if you come into contact with it, on what is called a warm roof.  Otherwise, the insulation will be on the floor of the loft and won't affect the job.

Once the insulation and the underlay are sealed, the frame of the window can now be placed onto the rafters and fitted as instructed, usually using the fixing brackets.  Next into place is the flashings, which come in a kit to coordinate with the window you have chosen.  The manufacturer will tell you any specifics for your chosen product, so follow these instructions carefully.  The flashings are part of the waterproof seal you are creating around the window, so their correct fitting is very important.

Finally, the roof material is placed around the window, covering the flashings as instructed.  It may be necessary to cut the tiles to fit correctly but it is important that they reach the window frame so that all of the elements of the roof can work in harmony.  Once this is done, the glazed section of the window is now ready to be put into place and the job is complete.

Conclusion

When it comes to fitting a roof window, remember that the choice of which is correct is influenced by what the loft is going to be used for.  Check with building regulations to see what you can and can't do with the windows and always seek help if you are unsure.

 

Reference URLs

http://www.fixmyroof.co.uk/videos-and-guides/roof-windows/fitting-a-velux/

http://www.keyliteroofwindows.com/fitting-instructions

http://www.therooflightcompany.co.uk/assets/pdf/Other/haynes-manual.pdf

http://www.fixmyroof.co.uk/videos-and-guides/roof-windows/fitting-a-velux/