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High-quality residential developments are no longer defined only by their location and standard of finish. Stunning architecture, luxurious interiors and high-end amenities are still expected, of course, but there is something else to add into the mix: sustainability. A new home or high-rise development doesn’t have to be labelled as an “eco home” to be part of the sustainability conversation. Whether driven by the client, the architect, or the two working in collaboration, better standards of energy efficiency and comfort, along with healthier interiors, are now normal aspirations. The blank canvas of a new project offers the opportunity to deliver much more than the minimum standards required by building regulations. Project teams now routinely look to the promised Future Homes Standard – not due to be implemented until 2025 – as a benchmark for performance. As a component of the building envelope that must balance energy efficiency with providing natural light and views out, rooflight specification plays a big part in whether that benchmark is achieved. What is the Future Homes Standard? The Future Homes Standard is the name given to proposed changes to the Building Regulations in England, expected to take effect this year. It is not one single standard or document, but the combined result of updates to Part L (conservation of fuel and power), Part F (ventilation) and Part O (overheating), as part of the wider Building Regulations. The current stated intention of the ‘Future Homes Standard’ is for new residential properties to deliver an average reduction in carbon emissions of 75-80% compared to Part L 2013. Thanks to such significantly better performance, homes should not require energy efficiency retrofit measures in future. The eventual decarbonisation of grid electricity will account for the remaining operational emissions, meaning new-build homes will play their part in helping the country to meet its legally binding net zero carbon targets. How can projects be built to the Future Homes Standard today? Until it is consulted on and agreed, we don’t know the precise technical detail of the Future Homes Standard. However, there are two key elements that make it possible to deliver a new residential development today and claim alignment with it. The first is the knowledge of the intended carbon reductions. A development can be assessed against the version of SAP used by the current Part L 2021, with improvements made to the specification such even greater carbon reductions are demonstrated. The second element is Part L 2021 itself. The government introduced Part L 2021 with the specific intention of it acting as a stepping stone to the Future Homes Standard. It lays the groundwork for increased uptake of heat pumps, and the general electrification of properties, alongside much better building fabric standards. These will all be features of the eventual Future Homes Standard. Specifying rooflights to deliver Future Homes Standard levels of performance  Despite uncertainty around broader government policy, businesses are pushing ahead with their plans to help deliver net zero. The construction industry is no different, and projects are routinely looking to achieve performance above and beyond Part L 2021. Part of that is sensible risk management. Planning a project now to current regulations, only to find it then needs to meet the Future Homes Standard in just a few years, would require substantial changes to the specification. Much better to work to that specification now and create healthier, more comfortable and more energy efficient homes. High standards of building fabric performance, supported by low U-values and correct installation, are essential for meeting current or future regulations. Rooflights are part of the building fabric, so choosing high-quality components from a reliable manufacturer is essential. Rooflights have always played an important role in homes. They can provide a level and quality of daylight that facade glazing alone struggles to replicate. Better levels of natural light are good for the health and wellbeing of building occupants and can reduce reliance on artificial lighting – thereby saving energy. With greater focus on sustainability, installed rooflights must deliver the right thermal transmittance (U-value), solar transmittance (g-value) and, where required, ventilation to support the overall energy efficiency and comfort goals. That is true whether choosing from an existing range or having bespoke items created to fit a particular architectural vision Rooflights also must be capable of being installed within the surrounding roof, without creating a break in the thermal envelope and causing significant thermal bridging. Thermal bridging heat losses risk undoing all the intended performance goals for the dwelling as a whole. With overheating now a part of the Building Regulations, rooflights can play an even greater role. Alongside delivering daylit interiors, impressive views and desirable architecture, they can be positioned to limit solar gains. Their potential to provide natural ventilation might also be an answer in situations – such as high-rise developments – where achieving cross-ventilation through a property is not possible.

With increasing percentages of the working population working in remote or hybrid-remote conditions after the pandemic, the home office is becoming more popular than ever. Working in a comfortable home office is extremely important as it will allow you to be more productive and comfortable in your workspace. An easy way to transform your workspace is by adding a glass rooflight – Unlike regular windows, rooflights allow natural daylight to enter the room from above, making your office feel brighter and more open. The Benefits Of Natural Daylight Ensuring that your home office is well lit, naturally, is essential as natural daylight offers numerous benefits from increased productivity to physical health benefits.  The quality of light in a room can have a profound impact on the level of productivity. Exposure to natural daylight regulates the body’s circadian rhythm (The 24-hour sleep-wake cycle that naturally occurs internally) – The human body is biologically programmed to respond to light and dark cycles, with light being the primary cue for regulating these circadian rhythms. In addition to increased productivity, natural daylight can help enhance mood due to stimulating the release of serotonin, a natural neurotransmitter that contributes to feelings of well-being and happiness. Higher serotonin levels are commonly associated with better mood and higher levels of focus and productivity. The presence of natural daylight during the working day will trigger serotonin production, which can support increased mental clarity, reduced stress, and improved overall mood. As well as the mental health benefits, increased levels of natural daylight can enhance physical health due to the stimulated release of Vitamin D which is essential for maintaining physical health, including bone health and immune function. Installing a rooflight in any room will reduce the reliance on artificial sources of lighting, which can boast numerous benefits. Relying less on artificial lighting increases energy efficiency as the natural daylight will illuminate the space for longer, especially during the summer months. In addition, increased natural daylight reduces eye strain in turn reducing the likelihood of headaches and fatigue Optimise Your Space As well as the profound mental and physical wellbeing benefits of installing a rooflight in your home office, there are also practical benefits. Installing a rooflight will improve the aesthetics of the room, and working in a home office workspace that you are comfortable in will be essential to productivity and mood during the working day. This improved aesthetic appeal could also reap benefits in the future and increase the value of your home and make it more appealing to potential buyers. One of the main benefits of rooflights, aside from the increased levels of natural daylight, is that they can be installed in a room of any size.  Most flat rooflights on the market are specially designed to be installed on a builder’s upstand, meaning that it does not take up valuable space in your home. For example, rooflights like the Glazing Vision Walk-On Flushglaze are the perfect solution for unlocking the possibilities of your roof terrace whilst also allowing natural daylight to flow into the room below. The Perfect Rooflight For You With so many high quality rooflights on the market, it can be difficult to know which glass rooflight is right for you and your specific requirements; whether you require increased levels of natural daylight, ventilation or maintenance access to your rooftop. Choosing a rooflight that suits your unique needs is important, for a home office an increase of natural daylight is essential, however if you would benefit from increased levels of fresh air, especially during the summer months, you should opt for a ventilation rooflight such as the Glazing Vision VisionVent Rooflight which can be effortlessly opened with the touch of a button. If you require your rooflight quickly, our off-the-shelf rooflights are a great option as they can be delivered to you within a working week - Explore our flat rooflights now and receive your desired rooflight(s) in 3-5 working days.

Glass rooflights can have a huge impact on the influence of light in a building. It can be at the heart of the project or complement the space. The choice of options for glass rooflight design are now greater than ever and can be expertly used to bring light, air and space to projects. For residential designs, a rooflight can be used for single property renovations in cities where both space and light are at a premium to glazing solutions, bringing the natural beauty of the outside in. The use of glazing for commercial applications ranges from stunning, light enhancing designs to specialist glass applications. Regardless of the project and inspiration, there are many considerations in the design and specification of glass rooflights: What classification is the rooflight? Where is it being installed? What is the building type? Commercial, residential, public? Glare and solar gain considerations, what glass should you use? What is it being used for? Daylight, ventilation or access? What do you want the rooflight to achieve and what other considerations should be taken into account when specifying? In addition, the following factors should also be considered about the building type and its location within that building: What function does the rooflight perform? Will the rooflight be subject to foot traffic? Will it be positioned where it is subject to high thermal stress? Can something fall on the glass? Is it easy to clean? Will it cause an obstruction to other parts of the building? What preparations should be made to the roof structure in order to adequately support the rooflight? If the rooflight opens, do the electrics and transformers need to be housed within the building fabric? What is the lead time and how may this affect other trades such as plasterers, roofers of electricians? Will any of these considerations affect the glass I need? To understand more about the design and specification of glass rooflights, please contact our experienced team or explore our range of rooflights.

Part F of the Building Regulations in England sets out requirements for ventilation. The current version is Part F 2021, which is expected to be replaced by a new version later this year as part of the overarching Future Homes Standard. Wales and Scotland have their own ventilation requirements, albeit the overall aims across the different countries are similar. Appropriate levels of ventilation protect the health of building occupants by avoiding mould and poor indoor air quality. Achieving the right rate of ventilation is essential for meeting current or future regulations in all parts of the UK. Rooflights have a role to play in ventilation control for dwellings, particularly in terms of providing the option of purge ventilation. What are the requirements of Part F 2021? As detailed in Approved Document F volume 1, Requirement F1 is broken down into two separate aspects. Requirement F1(1) is that there shall be adequate means of ventilation provided for people in the building. Requirement F1(2) is that fixed systems for mechanical ventilation and any associated controls must be commissioned by testing and adjusted as necessary. Ventilation strategies can be delivered by mechanical means, natural means or both. Part F 2021 supports each of those options. Requirement F1(1) is met if the ventilation strategy for a dwelling: Extracts water vapour and indoor air pollutants; Supplies a minimum level of outdoor air; Can provide purge ventilation to rapidly dilute pollutants and disperse vapour; Minimises the entry of external pollutants; and Keeps noise to a minimum, can be maintained and provides protection from cold draughts. How can rooflights help to achieve Part F compliance? High levels of ventilation are good for occupant health, but excessive ventilation increases energy use. When heated warm air is lost – in either a controlled or uncontrolled manner, depending on the quality of the construction – the cold air that replaces it must be heated. It therefore makes sense to avoid extra load on the heating system by making ventilation as efficient and effective as possible. Mechanical ventilation systems providing a predictable, consistent and controlled supply of fresh air are increasingly seen as the preferred solution. Simple extract fans are mechanical, but more sophisticated, whole-dwelling solutions can include heat recovery. That means the warm air extracted from the building is used to heat the incoming cold air, lessening the reliance on the building’s heating system. Natural ventilation is mostly driven by external air pressure and air movement, which can fluctuate and might not be entirely dependable on days when it is most needed. Arguably, natural ventilation should be viewed as a supplement to a mechanical system, to take advantage of the days when it is most effective. Paragraph 1.9 of Approved Document F volume 1 says that whatever solution is adopted for a residential dwelling, the overall strategy should be capable of delivering the following. Extract ventilation in rooms such as kitchens and bathrooms. Whole-dwelling ventilation to provide fresh air and remove pollutants not dealt with by extract ventilation. Purge ventilation to remove occasional high concentrations of pollutants. Extract ventilation is only possible via mechanical means, but rooflights can play a meaningful role in the other two areas of ventilation strategy. Where they really excel is in providing additional options for ventilation control, either in individual rooms or the dwelling as a whole, that may not be possible with façade windows alone. Rooflights are an excellent way of helping to achieve cross ventilation through a property where openings on opposite sides of a building are not available or don’t readily align. Using rooflights to go beyond the minimum standard of Part F Like all areas of building regulations, Part F only sets out a minimum standard. The option to go beyond the requirements is always available and is particularly worth considering when it comes to ventilation. A frequent criticism of regulations in recent years is that requirements in one area don’t complement the requirements in another area. The most common example of this issue is how ventilation rates have failed to keep pace with increased levels of insulation and airtightness aimed at improving energy performance. Without a corresponding improvement in ventilation, indoor air quality has worsened, and overheating risk has increased. Changes to the regulations are only just beginning to overcome this disconnect, with Parts F and O now aligning better with Part L. However, designers and specifiers of prestigious homes and high-end apartments can think holistically and deliver a joined-up approach – possibly by adopting voluntary standards as well – that benefits their clients and adds value to their projects. The blank canvas of a new project offers the opportunity to deliver more than the minimum. Project teams now routinely look to the promised Future Homes Standard, and factor in predicted future climate conditions, to benchmark performance now. Rooflights have always played an important role in homes, providing a level and quality of daylight that vertical windows alone struggle to replicate. And better levels of natural light are good for the health and wellbeing of building occupants and can reduce reliance on artificial lighting – thereby saving energy.

When selecting the perfect rooflight, energy efficiency is a critical factor to consider. Rooflight U-values measure thermal performance, indicating how well the product retains heat and helps reduce energy consumption. Rooflight U-values – What you need to know The thermal performance of rooflights, including the U-value they achieve, is an essential part of building fabric specification. Balancing outgoing heat loss with incoming daylight and solar energy all contributes to the wider sustainability goals of a project – including the overall thermal efficiency of the building, and the thermal comfort of its occupants. Designers and specifiers therefore need to understand what quoted U-values mean, and the relevance of other performance measures such as Ug-values. This post concentrates on how rooflights allow solar energy in and limit heat transfer out. However, for projects where daylighting is just as important a consideration, factors such as light transmittance and reflectivity must also be taken into account. Why can rooflights have two different U-values? Anybody involved with building design and specification should be aware of U-values as a measure of thermal transmittance (the movement of heat energy) through building fabric from warm to cold. The composition of roof glazing units – including overall size, relative areas of glazing and frame, and the thermal performance of the materials used – varies, so U-values quoted in a specification should be based on an actual product or a detailed calculation model. However, performance specifications may not be clear about whether a whole-unit or centre pane value is required. Manufacturers themselves may not be clear about the type of U-value they are quoting, creating the potential for confusion. In most circumstances, U-values should be for the whole unit, including glazing and frame. Whole-unit U-values can be improved through the use of a warm edge spacer. Traditionally, spacer bars are aluminium but, like any metal, aluminium has a high thermal conductivity. It acts as a thermal bridge, conducting heat from inside the building at the edge of the glass and bypassing features otherwise designed to improve the efficiency of the glazing. ‘Warm edge’ spacer bars use materials with a lower thermal conductivity to slow the rate of heat loss and create a more even surface temperature across the whole glass pane. Centre pane U-values address the thermal performance of the glass only. They appear lower than whole-unit values because the cold bridging effect of the spacer and edge seal are not accounted for. Unfortunately, this means some manufacturers rely on quoting centre pane U-values when they should offer whole-unit U-values. Specifiers can find themselves misled if a centre pane value is made to appear as though it is a better performing product. Centre pane values do have an application, though. They are useful for comparing one glass against another when being used in the same frame, as well as in conservation projects where traditional frame designs offer no meaningful thermal performance. Why should you consider rooflight g-values alongside U-values? Compared to the total surface area of the building fabric, the U-value heat loss through relatively small areas of roof glazing is more than offset by the contribution of solar gains and the reduced use of artificial lighting. The measure of infrared radiation (solar heat) allowed into a building is the g-value. A g-value can be anything from 0 to 1, where 0 represents no solar heat gain and 1 is the maximum possible solar heat gain. It is calculated by dividing the total solar heat gain by the incident solar radiation (the amount of solar radiation received on the surface during a given time). The lower the g-value, the lower the percentage of solar radiation allowed through the glass. Like U-values, performance figures can be quoted for the glass alone or for a complete glazed unit. Better, lower g-values also result in lower light transmission. How do different gases change the thermal performance of rooflights? Most people understand the benefits of having a glazing unit that is more than just single glazed. Double glazing, triple glazing and even quadruple glazing improve the thermal (and acoustic) performance by introducing sealed layers of gas between the panes. A well-known feature of products is to fill the sealed space between panes with an inert gas like argon, whose thermal conductivity is some 34% lower than still air. Some manufacturers use krypton and xenon, both of which offer further improvements in thermal efficiency, but which are more expensive. Do low emissivity coatings impact on rooflight U-values? The function of low emissivity (low-e) coatings is to impact on the loss of solar radiation back out of the building. A material’s emissivity determines the amount of thermal radiation emitted from its surface. Low-e surfaces emit less thermal radiation, and glazing units benefit from this through the application of a microscopic coating of tin, silver or zinc to certain faces of the glass panes in the unit. In contrast to the short-wave radiation from the sun that heats the building interior, the heat energy transferring back through the building fabric, from warm inside to cold outside, is long wave radiation. Glass with the low-e coating reflects long wave radiation, effectively keeping more heat energy in the building. There are two types of coating: hard and soft. Hard coat is applied while the glass is still molten, whereas soft coat is applied later in the process. Hard coat is more durable, as its name suggests. Soft coat remains delicate, is only applied to the sides of panes facing into a sealed airspace, and has a lower emissivity than hard coat. The difference in emissivity between the two means argon-filled glazing with a hard coat treatment will typically offer a centre pane U-value of 1.4 W/m2K, while a soft coat treatment will see that improved to 1.1 W/m2K. It’s a meaningful distinction, yet some manufacturers will simply claim their glazing to be “low-e”. Making a hard coat treatment sound like a similar benefit to soft coat is another reason for specifiers to be clear about the features of the products they’re selecting.

Rooflights and roof windows are both popular choices for bringing natural daylight into a property, and rooflights can also provide a variety of other benefits, such as natural ventilation and access to roof terraces. When selecting a roof window or rooflight for pitched roofs, there are several specification considerations to think about – and one factor that could play an important part in your decision is the pitch of the roof. Roof pitch affects drainage, determines how the units should be installed and even what type of products you can use. Below, we explain the different requirements for rooflights and roof windows; this should help you to decide which product is most appropriate for your project. Installing a rooflight on a flat roof When installing a rooflight on a flat roof you should ensure that the product is not fitted completely flat itself. Glass inherently has a degree of flex when installed flat (as opposed to vertically as you would find in traditional windows and doors). This is known as ‘deflection’ and means that without pitching the rooflight up slightly at one end, rainwater will accumulate and begin to ‘pond’ on the glass. When this evaporates it can leave unsightly marks and stains behind. Manufacturers therefore recommend a ‘minimum pitch’ to install their product so that rainwater and debris runs off the glass more effectively, keeping the rooflight cleaner for longer. The recommended pitch for rooflight installation on a flat roof For many rooflight applications on flat roofs, there should be a minimum pitch or fall of three degrees. This is enough to ensure that water will drain off the surface of the glass and avoid ponding. The higher the pitch, the more effective it is at draining off the water, so although three degrees is often the recommended minimum pitch, installing the unit slightly higher – for example at five degrees will prove more efficient. To achieve the required pitch, an upstand or kerb is usually constructed around the aperture in the roof, which will accommodate the slope into it for the rooflight to be structurally fixed to. If you are unsure, the rooflight manufacturer should provide drawings to indicate minimum kerb heights, which will allow your builder to calculate how high the top of the slope needs to be to achieve the desired pitch. Steeper pitches for rooflight installation on flat roof Rooflights can be successfully installed at steeper pitches, but for flat roof applications the height at the top end of the upstand will begin to be so great it will compromise aesthetics and potentially contravene planning permissions, which in some cases will limit the height of any structure that can be built above roof level. Depending on the rooflight design, installing on more harshly pitched upstands may result in fouling the framework, so you should always check with manufacturer drawings and recommendations prior to commencing works on site. Other considerations for roof pitch and specification Here are a few more things to think about in relation to roof pitch and specifying rooflights for pitched roofs. ● Deflection – There is a level of flex that will occur in all glazing – and it can be particularly apparent in overhead installations. Wind loads, snow loads and the weight of the glass itself can contribute to the amount of deflection, and this can hinder drainage. ● Orientation – Pay attention to the orientation of the rooflight so that you can maximise. For example, if a unit has a 5m width and a 1m span, it’s better to build the pitch into the span dimension so the water has less distance to travel. ● Capping – Because rooflights have minimal pitch, it’s a good idea to check products closely to ensure there is no external capping around the edges. This is because capping can trap moisture and dirt, which can result in unsightly messes and damage to the unit. The correct pitch for installing a roof window on a flat roof Unlike rooflights mounted onto an upstand, roof windows are installed in-plane, meaning they follow the pitch of the roof and are mounted flush with the surface. Answering the question: “What’s the minimum roof pitch for a roof window?” is also much easier to answer. Because the units follow the existing roof pitch they do not require any additional height at one end to allow for drainage. According to EN 14351-1:2006, roof windows should be installed on roofs with a pitch of at least 15 degrees. Roof windows should be CE marked against this standard. Rooflights, however, cannot be CE-marked because they are usually installed ‘out of plane’ on an upstand and are not considered roof windows. Please note that specific requirements may vary depending on the manufacturer. Always check that the specification meets your roof design.