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  • HPH359: External shading solutions – with Paul Morris

    HPH359: External shading solutions – with Paul Morris

    Paul Morris from Solar-Shield explains how external shading can help control solar gains and reduce internal temperatures, keeping your home cool as temperatures rise.

    Interview with Paul Morris

    Paul Morris is a third generation blind maker and external shading specialist at Solar-Shield: Exterior Shading Solutions. They aim to deliver a range of different shading solutions that not only help to keep your home cool during the summer months, but provide a more constant indoor temperature all year round. In this chat, Paul highlights the benefits of using external shading over internal blinds.

    Internal blinds aren’t effective when it comes to temperature regulation

    Paul begins by explaining the difference between internal and external shading methods and their ability to keep the heat out of your home. When the sun shines, it transmits short wave energy which as it passes through the glass in your window is absorbed by your furniture, floor or walls and is re-radiated as long wave energy. This long wave energy can’t pass back through the glass of your windows and as a result the heat is trapped within your home, creating a greenhouse effect.

    By using internal blinds, you may feel as though you are blocking the sun and therefore keeping the heat out, but the heat is still being absorbed by your blind and radiating that heat back into your room. External shading methods aim to absorb this short wave energy before it has a chance to pass through your window and to radiate it back outside as long wave energy.

    “So the simple thing is, stop the sun before it hits the glass and you solve the problem.”

    External shading has been popular in other Northern European countries for many years

    Paul debunks the common misconception that external shading is only for hot climates and explains that countries like Germany, The Netherlands and Scandinavia have been utilising the technology for many years because they understand the principles. The UK building industry lags behind, but as summers get hotter as a result of the climate crisis, more people are beginning to recognise the value of external shading.

    External shading offers year long benefits

    Temperature regulation and heat reduction are often seen as the primary benefit for installing external shading. However, Paul also highlights that they don’t just act as heat gain reducers. They can also insulate, provide privacy and let you control light levels.

    “So some people will have external blinds on the north facing windows, so that during the winter they can keep some of the heat in. There’s more than one benefit in using external shading.”

    Building regulations now address overheating

    Paul explains that there are two main markets for external shading: retrofit and new build. The retrofit market is the biggest and is often driven by the problem of overheating – people are getting too hot in their homes and therefore seeking solutions. New build homes must comply with building regulations (Part O), which considers overheating and one solution included in the guidance is external shading.

    External shading can come in many different forms

    External shading is not a one size fits all approach and Paul recommends looking at all of the different options to see which will be best suited to your home. External shading can be grouped into two categories: dynamic and passive (or fixed). The dynamic shading methods are ones which you can move and control, allowing them to serve different functions at different times of the day or year.

    Dynamic shading methods include external venetian blinds, awnings and roller blinds – which normally use a screen fabric with an open weave that allows a view through.

    Fixed shading is part of good house design and may include roof overhangs and deep reveals around windows. For example the overhang at Hazel Tree House helps shades windows from the high summer sun but still allows the low sun in during the winter when solar gain in required.

    Fixed shading can also be provided by pergolas, brise soleil or even a tree – features that are there all year round.

    Include external shading in your design as early as possible

    When approaching a new build or retrofit project, Paul recommends considering external shading as early as possible in the design process to ensure you have the most options.

    Your architect or designer should have a good grasp on this, optimising the orientation of your home and thinking carefully about the shading. If you’re building to Passivhaus standard, this is baked into the processes but the Passivhaus Trust has some excellent guidance on how to design for summer comfort.

    Whatever you decide, if you look at the options early the shading can be integrated much better into your building and there will be a seamless finish.

    “When planning shading, plan it early, that gives you the most options. Very often we get called in quite late, and I say to people, it’s going to be a compromise. If you want to reduce the number of compromises you make on your design, speak to people like ourselves early.”

    Dynamic shading can be radio controlled

    Although dynamic shading solutions can be operated manually Paul suggests automated controls, particularly as this shading is external and may cover many windows.

    If you’re hard wiring your blinds then the main consideration is power at first fix.

    However, if you have an existing low energy home and you’re worried about drilling through walls and insulation then there is another option.

    Some external shading products have solar Li-ion batteries which means there’s no need to wire them in. They can also be radio controlled from inside.

    “If we were living in Northern Norway and it was dark for months of the year, you’d get about 60 operations before your battery started to run out. So in this country, realistically, with having daylight most of the time, the battery isn’t going to lose its charge.”

    While exterior shading products can be used in conjunction with smart home technology, Paul prefers to use timers and set blinds on different windows to come into operation at different times. This method does require getting to know how the sun interacts with your building, but once you have worked out the schedule it is extremely effective.

    External shading is resilient to windy conditions

    A common concern surrounding external shading solutions is their ability to withstand strong winds. Paul explains that all external blinds have wind ratings and combined with a wind sensor, they can be resilient in windy conditions.

    External venetian blinds are stable and will go up to 17 to 22 metres per second of wind before they need to be retracted. External roller blinds have a greater resilience, whilst awnings will need to be retracted at lower wind levels. Paul recommends having a wind sensor on all external products to automate these retractions and act as a fail safe.

    “No matter where you live, whether you’re on the Western Isles of Scotland, down a valley with the wind whistling up it, at the top of a hill, they’re a lot more resilient to wind than people realise.”

    MicroLouvre is the top choice when it comes to sustainability

    Paul recommends MicroLouvre for those looking for a sustainable solution to external shading. MicroLouvre is a passive external screen that is manufactured from 80% recycled materials. It has a 60 year lifespan and is 100% recyclable at end of life. During its life, it uses no power whatsoever and is maintenance free.

    Fitting your home with external shading might cost between £5,000-£10,000

    The price of external shading solutions very much depends on the size and scale of your project. Paul explains that the average order for a new build is between £5,000 and £10,000 but can be more for larger projects. While there are benefits to having external shading for your whole house in practice there is a law of diminishing returns so prioritising the problem areas first is a good approach.

    “If we’re talking about a large set of bifold doors, say, 5 metres wide by 2.2 metres high, you could be looking between £2,000 to £4,000 depending on the product used.”

    Find out more

    Visit the website of Solar-Shield: Exterior Shading Solutions

    Go into more depth on integrating external shading into your designs in our training session in The Hub.

    Transcript

    Download the transcript of this episode.

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    Subscribe, rate and review us on Apple Podcasts

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  • HPH279 : A beginner’s guide to building terminology – with Lee Fordham from Architype

    HPH279 : A beginner’s guide to building terminology – with Lee Fordham from Architype

    Lee Fordham from Architype simplifies some of the terminology you might come across if you’re thinking about doing a sustainable self build.

    Interview with Lee Fordham

    Shortly after qualifying as an architect in 2004, Lee spent time travelling and working for architecture practices in New Zealand and Australia. When he returned to the UK he decided to pursue his passion for sustainable design and started working at Architype, one of the UK’s leading sustainable architects, where he is now an Associate Director.

    A beginner’s guide to terminology

    For those that are just setting out in their self build journey there can be an overwhelming array of technical terminology used that can be baffling to anyone outside of the industry. Lee takes us through some of the common terms that you might come across in a sustainable self build.

    Passivhaus / Passive House

    Passivhaus (Passive House in the United States) is a building standard that was developed in Germany around 30 years ago. Using physics, the aim is to reduce the performance gap between how the building is designed to perform, and how it actually performs.

    The aim is to make the building more comfortable for the occupants and reduce how much energy the building uses, which is done with a better quality of build.

    Liz and Mike Hill’s Passivhaus – designed by Architype

    The experts will use the Passivhaus Planning Package (which you’ll hear referred to as PHPP), which essentially is a very complicated spreadsheet of data that allows them to design a building that will meet the Passivhaus criteria. The contractor will use that information to construct the building, and a certifier will guarantee the work and certify it if it meets the required standard.

    Passivhaus plaque

    MVHR

    You’ll commonly hear a Mechanical Ventilation Heat Recovery system referred to as an MVHR. They’re most likely to be used in Passivhaus buildings, but not exclusively. It is a ventilation system which extracts the used air from inside a building. It takes the heat from that air and mixes it with fresh air which is being brought into the building from outside, to provide every room with fresh, pre-warmed air.

    The air is filtered coming into the building, and different filters can be used according to whatever is in the external air in that area.

    A key benefit over natural ventilation is the element of control over any given space, ie removing moisture from bathrooms etc.

    An MVHR for a domestic dwelling is roughly the size of a combi-boiler and will need to be incorporated into the building’s design.

    MVHR unit at Landsdowne Drive Passivhaus – Green Building Store

    Foundations / Footings

    These will usually be designed by a structural engineer and are what sit under the building to evenly transfer the weight of the building to the earth. The type you use might be dependent on what your ground conditions are like, but some examples are pile foundations, deep strip foundations and raft foundations.

    U-value

    A complicated one to explain, but essentially it’s a way of measuring how thermally conductive a component or a series of components (like a piece of glass, wall or roof) is. It is the rate at which heat travels through. The lower the U-value, the better it is.

    The aim is to have fairly consistent U-values across all the components in a building. Having just one element that isn’t consistent could act as a magnet for moisture and potentially damage the structure. This can partly be achieved by better insulation, triple-glazed windows etc.

    The U-values form part of the data that feeds into the PHPP system.

    Airtightness

    At a very basic level, this is about eliminating drafts in a building. It’s relatively easy to achieve but needs to be thought about at the design stage. At Architype they denote the airtightness layer on their detailed drawings using a red line, which shows the contractors where to take particular care in the construction so as not to damage it.

    To meet building regulations, when the building is finished an air test will be carried out. The building has a giant fan attached to it and is either positively pressured, ie blowing air in, or negatively pressured, ie extracting air. The rate at which the air leaks gives you your air test result. It is a measure in pascals of the pressure of an internal area. Building regs require you to get a result of 10 or less.

    The method in a Passivhaus building is slightly different. This takes an average reading from the building being both positively and negatively pressured, to give an n50 value which is how many volumes of air changes there are in an hour. The Passivhaus requirement is that it should be less than 0.6, so significantly better than building regulations.

    Build system / construction method

    This is a way of describing what method you are going to use to construct your building. Examples include timber frame, masonry, brick and block, insulated concrete formwork (ICF), pre-cast concrete, in-situ concrete, and cross-laminated timber.

    Pre-fabrication

    Pre-fabrication is where components, or indeed whole buildings, are made off-site. This could be from wall panels, to timber frames, to bathrooms that are fully plumbed and tiled, to entire houses.

    MAKAR production facility

    You can even go to the factories and choose your handles, paint finishes, floor finishes etc. When they reach the site they are connected together. The advantages of building the elements off-site is it can be quicker, they’re not subject to delays or damage from the weather, and often it can result in better quality and working better when brought to site.

    Huf Haus

    Zero carbon

    Lee says that this is a difficult one to explain as there are many different interpretations of what it means.

    Generally it refers to off-setting the energy use in a building. So the better your building is, ie a Passivhaus, the less carbon you have to off-set because you’re not using as much energy.

    Looking deeper into it, some people will be referring to zero carbon in use, which is the energy that is used starting from the point of when it’s been built, through to its end of life.

    But there’s also embodied or sequestered carbon, which takes into account everything to do with the design and construction of the building, together with the in-use energy and sometimes through to the demolition. This is more complicated to account for, although there are tools which can help explain for instance, how much energy is used in getting a tree from Germany to the UK to use in a timber frame.

    Custom build

    Whereas self build has many decisions for you to make, whether or not you’re doing it in the purest sense of building it yourself, or whether you’re commissioning someone to carry that out for you, custom build can take some of those decisions away from you. There will be an offering from the custom build company, but with options for you to customise it. That could be in terms of the style of the house, the layout or the finishes. It might not be as individual as you would get with a self build, but it can take away a lot of the headaches!

    Potton Homes design

    Solar shading / brise soleil

    Effectively the same thing, brise soleil or solar shading would be used on the south facing side of a building to limit the sun coming in during the summer months when you don’t want the building to overheat, but allowing it to come in during the winter when the heat is required. Generally it would be a horizontal component that sits over the south facing glazing, whether that be a roof overhang, external canopy or series of louvres.

    External louvres – Charlie Luxton Design
    Wimbish Passivhaus Scheme – Parsons & Whittley
    Ditchingham Passivhaus Scheme – Parsons & Whittley

    On an east or west elevation you would usually have a vertical component, and that’s just to do with the angle of the sun at certain times of day and certain times of year. Windows on the east and west elevation can be harder for dealing with glare and overheating issues.

    Lee says the ideal situation is to have the building facing south where the solar gains can be controlled more easily.

    Design team

    The core members of a design team are likely to include: an architect, structural engineer, civil engineer, mechanical and electrical (M&E) engineer, and possibly a project manager.

    Beyond that, depending on your site and your level of involvement and interests, you might also have: landscape architect, ecologist, arboriculturist, quantity surveyor, Passivhaus designer etc.

    Renewables

    Renewables refers to technology that generates energy. This could be photovoltaics, wind turbines, hydro power etc.

    Air source and ground source heat pumps

    An air source heat pump takes energy from the temperature in the air. Any air above zero degrees has energy in it and this can be taken and transferred into heat or hot water for your house. Similar in size to a washing machine, they’re put on the outside of a building.

    The ground source heat pump works in much the same way but will take the energy from the ground. They have pipes which can either be spread horizontally in the ground which will require a lot of space, or as a vertical spread of pipes, which need less space but are a lot more expensive.

    Plans, elevations, sections and details

    These are examples of the different types of design drawings, created by Parsons and Whittley for Ben Adam-Smith’s house:

    Plan – This is an aerial view, looking down onto the building. You can have different plans to show each floor of the building, but they can show the roof, doors, walls and windows, together with the internal layout.

    Elevation – An elevation is a drawing of what the outsides of the building look like from where you’re standing. A south elevation for example would be the side of the building that is facing towards the south.

    Section – This is like slicing down through a building to show what’s inside. It will show the components of the walls, floors, roof etc.

    Details – By taking a section drawing and zooming in you will create a detail. They can be various scales, such as 1:2 or 1:10, and are an in-depth analysis and instruction for the contractor showing how to construct that part of the building. It would show them where the airtightness line is, where the insulation is, and how wide cavities would need to be.

    Soft landings and performance monitoring

    A soft landing is about making sure that once the building has been constructed, that the operator of that building knows how to use it. Obviously if you’ve built it yourself then this wouldn’t be necessary, but if you’ve largely commissioned other people to complete the project then you should have someone tell you how it all works.

    Performance monitoring can take place throughout the build process but in particular Lee refers to monitoring once the building is complete. This uses sensors to check on things like the internal temperature, humidity and CO2 levels, to make sure the building is performing as it was designed to do.

    Tender

    The way you tender will depend on what kind of contract you will have, but essentially a tender is a set of information that is put out to someone for a response. They will price up the aspects on the tender and return it with their figure and requested documentation. It can be a tender for a design team or for a contractor. The returned tender documents are then scored and weighted according to whatever your priorities might be. For some that might be 80% of the marks will be based on how competitive the price is, but for others they might weight it more heavily in favour of quality and not necessarily who is the cheapest.

    A key thing is to make sure the information and drawings you are sending out are as comprehensive as possible. That way it can be priced accurately for what you will be needing. Without that detail they will be adding an element of price risk to their response which will invariably make it much more expensive.

    Window parts

    • Sill – The ledge at the bottom of the frame.
    • Head – The top of a window where it meets the wall. It can be internal or external.
    • Jamb – The side of the window
    • Reveal – The part next to the jamb. Can be internal (usually plasterboard) or external (usually timber or brick). If the reveals are set very deep into the thickness of a wall they can provide some shading to the window
    • Mullions and transoms – Found on traditional Victorian style windows, the mullions are the vertical bar in the middle of the window, and the transoms are the horizontal bar.

    Roof parts

    • Trusses – The pieces, usually made of wood, that actually make the roof structure
    • Joists – A horizontal structural element that supports the floor and/or ceiling
    • Eaves – The part of the roof that overhangs the wall. Usually if it’s a sloping roof it would be the part which overhangs the gutter
    • Soffits – Underneath the eaves, the soffits are the horizontal section that you can see
    • Ridge – The point right at the top of the roof, usually where two pitches come together
    • Verge – The part at the side of the house. Usually there would be a bargeboard or piece of wood that goes down the side
    • Parapet – Usually a piece of wall that protrudes up above a flat roof
    Roof trusses
    Roof joists

    Find out more

    Visit the website of Architype

    Follow Architype on Twitter

    Transcript

    Download a transcript of the interview with Lee Fordham.

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    If you’re new to self build and looking for more information, then be sure to check out The Hub. It’s full of great resources, video diaries and support from a community of like-minded self-builders.

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