Glass in Basements – Let in the Light

Glass in Basements

“This below floor level space adds a whole other floor”

Basement renovations are fast becoming the extension method of choice in high-density areas such as London. Driven by the need to add more usable living space into homes where extending above ground is not possible (be that due to planning policies or available size) the only way to extend is down.

The Commission for Architecture and the Built Environment (CABE) states that the UK builds are the smallest homes in Europe, so it is no wonder that extensions to create more habitable living spaces are required.

Basements are not a new concept; cellars and basements were a standard floor addition in most townhouses during the 19th century. This below floor level space adds a whole other floor and in some cases adds a third more living space to a property without changing the external look of a building.

“IQ Glass are fast becoming the architectural glazing experts in basement glazing”

IQ Glass is fast becoming the architectural glazing experts in basement glazing due to our expertise in glass, large glazing elements into underground zones and a learnt understanding of building regulation and architecture. Obviously, when digging down directly under an existing dwelling there is usually not an overly expansive space for vertical windows. Therefore, to make a basement extension usable, enjoyable and livable, you need to be clever and creative to get that much needed natural light into the space.

Matt Holmes from Home Building and Renovating points out that “light is a key ingredient for creating a quality living space so this should be a major factor in deciding the basement layout.”

The first and most straightforward way of getting light down into the internal space of the basement area is rooflights. Horizontal planes of transparent glazing in the floor spaces above will draw vertical light down into the basement space creating a bright, light-bathed environment. Walk on rooflights are an obvious way to do this as they do not impede on any floor space on the above floors. Placing these on southern elevations will bring in the maximum amount of light and if your basement extension runs out under your garden walk on glass panels embedded into the floor, decking or patio are great minimal solutions to light ingress below.

“The first and most straightforward way of getting light down into the internal space of the basement area is rooflights”

If the space is available, you may want to consider a sunken courtyard or lightwell down into the basement space. Here you can add vertical glass elements such as IQ’s Minimal Windows sliding doors, creating huge, flush finishes of transparent glass with frameless, minimal sightlines.

Once the light ingresses into the new space are designed thinking about the functional results of transparent surfaces into the building construction should be your next thought. For southern elevations, a solar control coating is the first port of call. These coatings reduce the amount of long radiation waves that can enter a space through the glazing and reduce the extent of overheating due to solar gain through glass. In areas where snowfall is frequent of heavy, you may want to consider using IQ Heated Glass on rooflights and glass floors. This specialist technical glazing solution will melt any snow or ice fall on the glass elements keeping them clear and transparent at all times of the year.

“Having rooflights translucent or sandblasted is a very straightforward way of ensuring that the glass aspects of a building are not impeaching on privacy”

Privacy is another aspect, for both those above and below. Having rooflights translucent or sandblasted is a very straightforward way of ensuring that the glass aspects of a building are not impeaching on the privacy of any occupant, but then will not allow vision through the glass at any time. An alternative option is to use a technical glass solution such as IQ’s Privacy Glass that can change from transparent to translucent with the application of electricity, leaving the choice up to the occupier.

For high thermal performances, IQ would suggest that any external rooflight or walk on glass element be specified as IQ’s Super Insulating Glass. To comply with part L of Building Regulations all windows and doors must have a Uw value of 2.0 W/m2K or less; IQ’s Super Insulating Units carry a standard u-value of 0.7 which will not change if used as a rooflight.  It is no secret that heat rises and therefore these elements at the top of a space need to have the best thermal performance. Glass is at its least effective when titled horizontally due to the convention current heat loss through the glass or air fillings inside a unit. By using IQ’s Super Insulating Glass you eliminate that heat loss due to the structural makeup of the glass and film these convection currents don’t form, so no dip in performance from this highly insulating glass panel.

Switchable Privacy Glass at the IQ Showroom
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“Glass Balustrading, open threaded steps, glass steps and full length, double storey windows will all allow light to filter from above”

At the access points to your basement, glass can play a critical role in ensuring maximum light transmission. Using transparent items in your entry and exit points allow light to seep uninterrupted through the necessary opening into the basement area. Glass Balustrading, open threaded steps, even glass steps all will allow light to filter from above, for a higher end solution glass lifts shafts can be used.

If a basement is to be used as a habitable space escape routes need to be planned into the design in the event of an emergency of fire. Using Fire Glass around the exit points will ensure that these emergency exit routes are protected and will stop fire spreading to these must have escape routes.

Once the light is actually in the space you need to create spaces for the light to flow through. An open plan basement is obviously ideal for this with the usable living spaces planned where the light levels will be highest. Further into the basement using glass partitions to divide the space is a great way of allowing this light transmission to continue.

“IQ’s minimal detailing allows for these internal glass panels to be full height and frameless creating for nearly 100% light transmission”

IQ’s minimal detailing allows for these internal glass panels to be full height and frameless creating for nearly 100% light transmission through the elements from floor to ceiling. There is no minimum height for basement ceilings under Building Regulations but a practical minimum height of 2400mm is usually adhered to. Obviously, if it is structurally and economically viable, digging deeper to create higher ceilings gives the basements space a much more open feel.  If privacy is a thinking point between the spaces privacy glass can be used here on this internal element to create a controllable vision through the glazing with little change in light transmission between the two spaces.

“Condensation and glass can be a problem in these high humid environments. By introducing IQ Heated Glass into these glazed elements you eliminate any condensation”

Building basement gyms, pool, steam and sauna areas are very popular. Condensation and glass can be a problem in these high humid environments. By introducing IQ Heated Glass into these glazed elements you eliminate any condensation build up on the glazing leaving the glass clear and all the surrounding finishes minimally detailed without ugly floor grates used in conventional condensation removal.

If it is wanted to make these internal screens a more decorative aspect, using various methods of decorative glass will allow light transmission whilst creating a decorative elevation, either by using Kiln Formed Glass or laminating various elements in the glass itself to create the decorative aspect.

Contact IQ Glass for more information about using glass to sensibly maximise light transmission through your home, basement or extension.

www.iqglassuk.com (0)1494 722 880 hello@iqglassuk.com

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Rebecca is Head of Marketing at the IQ Group and has worked in glazing specification for many years. She has a broad range of technical knowledge about all our glazing products and offers technical advice and guidance to architects for specification. Her easy to digest technical advice is often quoted in magazines and publications. You might also recognise her as one of the IQ Glass CPD presenters.