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  • HPH284 : Build It magazine’s Self Build Education House – with Calum Taylor and Opinder Liddar

    HPH284 : Build It magazine’s Self Build Education House – with Calum Taylor and Opinder Liddar

    Calum Taylor and Opinder Liddar talk through the design and construction of the ‘Self Build Education House’ at Graven Hill.

    Interview with Calum Taylor and Opinder Liddar

    Calum Taylor is the owner of Build It Magazine, the longest running self build magazine in the UK. Together with their website and exhibitions, their aim is to provide expert advice and information in a practical and down to earth manner, to help self builders make the difficult decisions as easy as possible.

    Calum has been working on Build It’s Self Build Education House at Graven Hill with Opinder Liddar. Opinder is a director of lapd Architects. They are based in Oxfordshire and specialise in residential projects, particularly for self builders.

    It is a showcase of possibilities

    Coinciding with Build It magazine’s 30th anniversary, Calum’s idea for the Self Build Education House was to showcase the possibilities available to self builders by demonstrating the processes and some of the products that can be involved in a self build journey, whether or not they themselves were building at Graven Hill.

    It would also be a great experience for Chris Bates, the magazine’s editor, to have hands-on involvement with the project management.

    The house has been built on the Graven Hill development

    Graven Hill is a ground-breaking development: the first of its kind in the UK. The land was formerly owned by the Ministry of Defence before being sold to Cherwell District Council to develop. The site has planning permission for 1800 new homes, up to half of which are designated for self build.

    Calum says it has its fair share of cynics however, who question the plot sizes as being more like developer plots.

    “But I think it’s incredibly important that for self-build to really become the norm in the UK as opposed to what is done by a relatively few, relatively wealthy people, that we need to look at different models and we need to look at how you can have fantastic housing on smaller plots of land. And if you can do that with the profit on the land going back into the local community via the council then that strikes me as being a perfect model.”

    The plot passport outlines the parameters

    A number of plots had been allocated for show home use and, following a tender process, Calum successfully won a corner plot around the back of the houses featured on Grand Designs: The Street.

    Each plot comes with its own “plot passport” which defines certain parameters, such as maximum height and the footprint of where the house needs to be. With those established, the design can begin to develop as a response to the site aspects.

    It needs to work as a showcase, and a home

    In five years’ time the function will change from show house to a home that will be lived in, and this consideration formed part of the brief. It needs to have enough space for people to walk around in, while still feeling like a home.

    “Primarily we want people to look at it as ‘I want to live here. This is an amazing house.’ We don’t want them to think, ‘this works very well as a museum.’”

    With a plot restriction of 160m², the design was put in for planning at a size of 150m². The Graven Hill calculations don’t include basements and void spaces, so together with a basement plus an attic that would be prime for conversion, the overall area is closer to 230m².

    The budget has been for high-end specification

    Calum explains that the budget is rather difficult to define, as it’s not being constructed in the usual way. Typically a similar house might cost £2,000 per square metre, or around £470,000 in total. But as Build It’s complete guide to the house highlights, you could build the same size of house for substantially less if it wasn’t to the same high level of specification.

    By adding in the expensive finishes and details, Calum explains that it is giving people the opportunity to look at where they want to be spending their chunks of money.

    The corner plot dual aspects led much of the thought about design

    Opinder also likes the aesthetic of a steep roof pitch on a house, and to make a dramatic feature of the front he designed two gables, with the feature continuing around to the side.

    Insulated Concrete Form (ICF) was chosen as the construction method for a variety of reasons: it has good energy efficiency, is very airtight, performs well acoustically, and was particularly well suited for constructing the basement.

    Following discussions with Nudura, their ICF supplier, Opinder decided to push the design and show the materials at their best. The resulting design has a balcony that projects over the car parking area, hanging off a cantilevered wall that flies out at the first floor level. There are also frameless windows that turn the corner and are taken up to the underside of the gables.

    The ‘wow factor’ was an important consideration

    Often the space required for a plant room is underestimated, so the Build It house is a good example of showing how much area can be needed. Their plant room is in the basement to house the mechanical ventilation with heat recovery (MVHR) system, along with the inverter for the solar panels, battery storage, water softener, control hub for the Niko smart home system, and the amplifiers for the whole house sound system.

    Calum wants visitors to have the ‘wow factor’ when they walk in, so Opinder has designed a triple-height entrance hall. There you are greeted by a sculptural ash staircase that winds its way up. The eye is also drawn through towards the back of the building and the garden.

    A mixture of door types have been used, with pocket doors that slide into the walls, and a glass screen that gives the flexibility of sub-dividing the open space if needed.

    There is further architectural interest on the ground floor, with a curved wall that comes around from the cloakroom and into the kitchen, next to the floor to ceiling windows that give an amazingly light and spacious feel.

    The ground floor is open plan with lots of hard surfaces, but the oblique angles stop it from being acoustically noisy.

    The timber posi-joists, which are great for running services through, can be prone to noise transfer, so they have used acoustic boards, acoustic insulation and a screeded floor on top.

    On the first floor there is a glass balustrade which further enhances the connection with the outdoor space.

    Each bedroom is individual because of the different aspects and how they sit within the roof forms.

    It has been a typical self build journey in many ways

    The project hasn’t been without its challenges along the way.

    Calum explains that many of the difficulties have been in the project management of coordinating suppliers and contractors to work together.

    Issues were with communication, building to the same tolerances, and even incorrect measurements on site meaning that windows and doors didn’t end up exactly where they should have been.

    His tip for self builders is to keep on top of checking things like that because you could be storing up problems for a later date if things aren’t nipped in the bud as soon as possible.

    “The problems are about people and communication and scheduling things and dealing with the weather and all of those little curve balls that come your way and how you can actually try and continually pull it back to keeping it true to the vision of what you’re trying to create and as originally in the plans. Because it can be quite easy to deviate off slightly and end up with a house that doesn’t quite look and doesn’t quite perform in the way that you hoped it would.”

    The house shows what can be achieved on a tight plot

    With Calum working on the house from a Project Director level, it has been Editor Chris Bates who has been project managing the self build, going through the hard learning process and gaining valuable lessons and insights from it.

    Regular readers of Build It have been following the journey in the magazine and have been visiting to see the finished building. And for other members of the public with no prior experience of it, there are infographics around the house that help them understand the journey and the choices that were made around materials and suppliers.

    Going forward, the house will be paramount to the magazine’s editorial, as they can relate back to the experiences and decisions they made, or what they might have done differently in another scenario.

    Although the house went over budget and needed their contingency fund, (primarily due to weather delays), Opinder is keen for the house to show what is achievable on a fairly tight plot. He says it shows that it can be attainable for everybody and offers a genuine alternative to buying a typical “Noddy-box” house.

    More Graven Hill podcasts

    We’ve been following the Graven Hill scheme with interest for some time, so if you would like to know more about the background of the project and what it’s like to build there, then check out some of our previous podcasts:

    Find out more

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  • HPH181 : Improving acoustics, noise control and soundproofing – with Jack Harvie-Clark

    HPH181 : Improving acoustics, noise control and soundproofing – with Jack Harvie-Clark

    Jack Harvie-Clark from Apex Acoustics provides an overview of acoustics in the home. He also explains how we might go about controlling noises and soundproofing.

    Photograph by Martin Neeves Photography

    Interview with Jack Harvie-Clark

    Jack Harvie-Clark’s background is in engineering. His work in acoustics started when working for mechanical engineers in the power generation industry. A change to Building Regulations in 2003 meant a growth in acoustics in the construction sector and Jack set up Apex Acoustics in 2006. His work is concerned with the acoustics of buildings and how noise affects people’s health.

    Acoustics is about how sound travels

    Sound travels through structures as vibrations, and acoustics distinguishes between two concepts: sound insulation is how you stop the sound transmitting from one room to another; sound absorption is about how quickly the sound within a room gets absorbed.

    Jack explains that your ears know immediately when you’re in an enclosed space like a room, rather than outside, because you hear many reflections. Some reflection is very useful because it adds volume to your voice, but too much can be uncomfortable. Jack says that someone building a home should consider the room acoustics and how good they want it to be.

    There are restrictions for sound levels between attached dwellings

    Jack provides assistance for projects that need to comply with Building Regulations. People rarely call him just to make the acoustics better on their build; rather they want a competent specialist to help them meet the required standards.

    Building Regulations are mostly concerned with sound insulation between attached dwellings; so much of Jack’s work is on the airborne sounds through walls and floors and impact sounds through floors between flats.

    Reducing noise from neighbours may require sacrificing space

    If a client has a noisy neighbour, Jack will firstly find out whether there’s a problem with the wall that can be rectified. Then he has to interpret the client’s needs, to balance noise reduction with space lost and money spent. Jack explains, “You might think maybe they want it to be 10 dB quieter or 20 dB quieter. And then we’ll suggest the sorts of things they would need to build to achieve that.”

    Noise levels shouldn’t interfere with sleep or cause any annoyance

    Jack often advises homebuilders on how to keep out external environmental noise in order to comply with planning conditions. By considering the building plans and measuring the noise level outside they can recommend the required type of glass for the given window sizes and any appropriate treatment for the ventilation system.

    Whether or not there are planning conditions, noise levels outside might make you reluctant to open your windows. So Jack says good design should account for this.

    Rules on sound insulation between rooms aren’t very demanding

    Noise between internal walls is covered in a small way by Building Regulations. However, they don’t ensure any particular level of sound insulation to rooms that might be sensitive from other rooms within your house. Jack’s advice is to be sure to consider the issue of noise through floors and walls between rooms.

    There are ways to reduce noise between and within rooms

    In the design of a room the door will be the weak spot for sound transmission, including the gap at the bottom. Acoustic doors and an acoustic seal on the bottom will improve performance.

    In a house with ventilation, noise can sometimes travel from one room to another through ducts. You can improve sound insulation by including crosstalk attenuators in the vents, which let the air through but not the sound.

    Rooms designed for recording sound need to have minimal reverberation. Sound absorption can be achieved by putting carpet on the walls and similar use of soft furnishings.

    Large and high spaces need more sound absorption

    Rooms with higher ceilings or larger volumes are naturally more reverberant and can feel noisy and echoey. The noise level will increase dramatically when more people are in there, says Jack, especially if you have children! The more sound absorption you put in, the more comfortable it will be.

    The earlier the better where acoustic advice is concerned

    Jack says that acoustic consultants always get brought in too late, or only asked to look at very small bits of very big projects. He understands this, as you don’t want to build your whole house around the acoustics, but says if it were his house, he would want someone like him to look in more detail.

    Some audiophile clients might require advice about how rooms respond to sound. Jack can advise on the shape of the room, and recommends that wires for the sound system are planned as part of the electrical works, to avoid more holes in the walls later.

    Ventilation systems are designed to deliver and extract air, not to limit noise

    As most people will have some kind of ventilation system, Jack says that attention should be paid to getting the acoustics right. This could start with a specification for noise that the builder or the designer has to achieve, so that it will get taken care of in the design. In a Passivhaus, noise levels must not exceed 25 dB(A) in living spaces and 35 dB(A) in bathrooms; noise levels that are very unlikely to annoy.

    For other houses, the Building Regulations are less stringent and their legal requirement is even debatable, so they’re not being enforced. Many new houses have some form of mechanical extract, but Jack says that nobody is checking or designing the noise levels for these systems. This presents a big problem: people turn the fan down to reduce the noise, but that then means that they’re not getting enough air.

    Racecourse Passivhaus project – measuring the noise levels from the MVHR

    Mechanical ventilation systems need to be designed and maintained properly

    Absence of design, poor procurement and bad installation can be typical of ventilation systems in current mainstream housing. According to Jack, problems include:

    • houses handed over with dirty filters
    • residents not knowing they’re supposed to change the filters
    • residents not even knowing they have a ventilation system running

    Inadequate ventilation in airtight houses can lead to health problems

    Mechanical ventilation systems have become more common in new houses as a more efficient way to meet energy performance requirements. However, recent research has suggested that people prefer to control their internal environment by opening windows. Jack warns that if ventilation systems get turned off in very airtight modern houses, you can get health-related issues such as poor air quality and mould growth.

    Furthermore, opening windows to provide additional ventilation is the default method to mitigate overheating. However, there is no current assessment for resultant noise so if you’re building in a noisy place, Jack advises bearing in mind both how you provide the ventilation and how you control overheating.

    Award-winning double height open plan house – gaps between the timber laths provide the sound absorption with acoustic absorbent material behind

    Find out more

    Visit the website of Apex Acoustics

    Follow Apex Acoustics on Twitter

    Transcript

    Download a transcript of the interview with Jack Harvie-Clark

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