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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

    Please connect with me

  • HPH168 : An example of how much it costs to hire an architect – with Allan Corfield

    HPH168 : An example of how much it costs to hire an architect – with Allan Corfield

    Allan Corfield from Allan Corfield Architects (ACA) explains how his approach to services and fees differs from traditional architecture practices in the UK. He describes the staged services his practice offers, giving indicative costs.

    Interview with Allan Corfield

    Allan Corfield is an architect who aims to educate and help homeowners deliver their one-off dream home. He’s spent the last eight years building his practice based in Scotland focusing on self-builds. Their location isn’t an obstacle to working further afield as Allan factors into each fee proposal two or three face-to-face visits during each stage. Currently working on their 250th project, they now operate across the UK and are involved in projects with construction costs ranging from £70,000 to £2 million.

    Percentage-based fees will increase if construction costs go up

    Allan’s approach is different to the majority of traditional architecture practices in the UK who work on a percentage basis, charging 7-10% of the construction cost for their services. Allan prefers his approach because self-builds have a set budget and if you don’t know what your architect’s fee is going to be, you can’t plan ahead. He also argues there’s no incentive for an architect to save you money if their fee will drop in line with reduced construction costs.

    As can be seen on the ACA website, Allan’s practice splits the build process into different stages which are priced separately as fixed costs. This allows self-builders to budget for architectural fees knowing they won’t change as the project goes on. At the end of each stage, ACA asks if clients are happy to go ahead with the next one. Allan recognises that a self-builder may run out of money or there may be a change in family circumstances meaning they can’t commit and finish their project. So his approach offers flexibility and the ability to stop if necessary.

    An example of ACA’s fees based on an estimated construction cost of £250,000:

    StageFixed Cost (excl. VAT)% of Total Fee
    Initial Design Development£5,00025%
    Planning Submission£4,00020%
    Detailed Design Development£6,00030%
    Production Information£4,00020%
    On-site Supervision£250 per visit (optional)5%

    A detailed project brief is essential for the design stage

    Allan explains, “You want to get a design that you love, so that’s our initial design stage”. The most important thing for a client to get right is the project brief. ACA encourage clients to think about how they’ll use their buildings, e.g. an outdoors family may benefit from a wet room attached to their garage. Clients considering details like these help the architect design a home, not a house. ACA ask clients to create lots of different Pinterest boards, including a dislike board, as this helps them gauge what clients like aesthetically.

    ACA use the client’s project brief to propose a couple of initial design options, usually two variations on a theme. Often a third option evolves by combining preferred elements from the first two, which is then typically revised a couple of times until the client’s happy. Their design service ranges from 2-D drawings for lower budget projects to full 3-D modelling where clients can ‘walk around’ their house.

    The first stage also includes a cost check to ensure the design is affordable and self-build elements are achievable. And if there are any contentious elements that could affect planning permission, for example rural location, they make a pre-application enquiry or get a planning consultant in during the design stage.

    Make neighbours and planners feel they’re part of the process

    The cost of the planning stage may seem high but a lot of work goes into getting a planning application approved. Allan explains their high success rate is due to the amount of supporting information they provide, saying, “We’re very good I think at getting a lot more of our clients’ desires through the planning process than other practices because we give really good rendered images.” The thinking behind their design is explained in detail using a Design & Access Statement accompanying the application.

    ACA always ensure they know the local planning policy. Allan comments, “Actually it doesn’t matter where we are or where we come from. If you know the regulations and why you’re going to get something through planning, you shouldn’t have an issue.”

    Before submitting an application, Allan recommends clients discuss their drawings with neighbours so they feel they’re part of the process. While some may have objections, you can also benefit from letters of support.

    It’s advisable to get certification before starting to build

    The third stage is detailed design development. The architect and engineer will spend time researching and inputting information like SAP / PHPP calculations, but many things need to be confirmed by the client such as construction methods, materials, finishes, heating strategy and the level of energy performance.

    Within England’s building regulations system there’s an option to give notice to start work followed by a drip feed of information as the build goes on. Allan realises this can seem attractive to self-builders who may have experienced delays and be eager to get started. However, he prefers to put together a well thought out and detailed package for review and approval before construction starts (as is mandatory in Scotland), cautioning, “If you do rush ahead it will always cost you more in the long run.”

    Construction drawings show how the design should be built

    Stage 4 is called Production Information. The level of detail required in the previous stage demonstrates compliance with building regulations but doesn’t show precisely how the design will be built. Construction drawings are particularly important for self-builders, to ensure contractors use the methods agreed between client and architect.

    With low energy buildings or fabric first approach, you’ll need to have all the details worked out because there may be methods and products that are new to the builder. And with off-site construction methods, it’s down to the client to review and sign for a set of drawings and make sure they’re in line with the window and door schedule (e.g. ensuring the window openings match the kit size), so the cost of retaining your architect to help make sense of the complicated documentation is money well spent.

    You may not need as much on-site supervision as you might think

    The final stage is on-site supervision. In England, building control inspectors visit the site to assess work and provide assistance, but limited funding in Scotland means they don’t have time to come out, so you don’t have that safety net.

    Traditional architects often ask for a monthly retainer for site visits, but Allan feels this shouldn’t be necessary if the architect has provided all the required information and you’ve hired competent contractors. So ACA usually provide an adhoc service for this stage, charging a fixed price per visit if the client requests one. The exception to this is when ACA provides mortgage certificates, where they have to certify a phase of work (e.g. groundworks) has been completed before the lender will release the next chunk of money.

    Architects should be able to justify their fees

    When a project ends, ACA compare the time spent on that project versus fees charged. Quarterly reviews also help to ensure their fees are set appropriately, which will vary according to a client’s budget and requirements.

    Allan comments that building your own home is a very personal thing, and the deciding factor when choosing an architect shouldn’t be solely cost. He acknowledges his practice is slightly more expensive than some of their competitors (but a lot more cost effective than a comparative practice down south, even accounting for travel costs) and justifies their fees, saying, “We’ve got a better team, so we can charge the fee that we do because we actually deliver on what we need to.” He adds the majority of their clients take the full service through stages 1-5 and nobody has come back and quibbled over the fee.

     

    Find out more

    Visit the website of ACA

    Follow AC Architects on Twitter

    A big thank you

    Ben would like to thank Chris Marr from the Content Marketing Academy for connecting us to Allan and for facilitating the interview.

    If you’re a business owner, looking to serve your customers better in our digital world, it’s definitely worth learning more about what Chris does.

     

    Transcript

    Download a transcript of the interview with Allan Corfield

    Please connect with me

  • HPH153 : How to comply with building regulations – with Phill Skill

    HPH153 : How to comply with building regulations – with Phill Skill

    Phill Skill explains what building regulations are and how we comply with them.

    Phill 1

     

    Interview with Phill Skill

    Phill Skill was Head of Planning at Stroud District Council for over 10 years and also featured in the BBC documentary series The Planners. Now he is the Lead Business Consultant at Stroud District Council as well as a member of the board at Gloucestershire Building Control Partnership.

     

    Safety is at the heart of building regulations

    Building regulations deal with the physical structure of a building and are there to make the occupants as safe as possible.

    For example, it deals with foundations, wall structure, floors and drainage as well as what happens in the case of a fire.

     

    As the homeowner, you are responsible if something goes wrong

    The onus of the building regulations is on the house owner, not the builder.

    Therefore it is a good idea to draw up a contract with your builder which will indemnify you in the case of issues.

    Phill says: “It’s not getting seventy-five percent and we’ll let you build it, it’s getting a hundred percent and we’ll let you build it.”

     

    The regulations themselves are simple to understand

    Looking at a copy of the building regulations (in England and Wales; Scotland is similar) the sections with a green background are the actual regulations. These lay out what is expected in broad brush statements.

    Phill paraphases: “Staircases should be built so you don’t fall down them.”

    Approved documents explain how to comply

    Phill continues: “For instance, stairs, it will tell you how high each step should be and how deep each step should be, what angle the stair should be.”

     

    In England, there are two ways to get approved

    While the Scottish system is different, in England approval can be granted upfront by submitting drawings to your local authority or it can be back-loaded by getting a building notice.

    i) Submitting drawings

    By submitting drawings prepared by a draftsperson or architect, the council will check them over and make sure they are compliant. If they are not, they will write to you and ask you to make changes.

    While it may take a few weeks to get your approval notice the main advantage is that you iron out any issues before you get to site.

    ii) Building notices

    No plans or drawings are required with this method so it is quicker, but there will be more inspections on site.

    Perhaps the biggest drawback is that you don’t have a contract between you and the builder. So, you don’t actually know what the builder’s going to build because you haven’t given him any drawings!

    Also if the building inspector asks you change something you’ll have to make those changes on site and at your own cost.

    Phill says: “I would never recommend to anyone that they build a house under the building notice method. They really should have their drawings sorted.”

     

    Work can be approved by either the council or an approved inspector

    An approved inspector is an independent person who verifies you are building in accordance with building regulations and they’re regulated by the Construction Industry Council (which is a QUANGO of government).

    Phill says: “A lot of approved inspectors work on a risk assessment, a bit like an insurance company. They will assess your job, your competencies, how many buildings you’ve built and then tailor their inspection regime to that. So, if you are a self-builder, doing it yourself, it’s going to cost you a lot of money because they’re going to have to come out more often. With the local authority, it’s effectively a fixed fee regardless of whether you’re Barratt’s or you’re Joe Bloggs.”

    Phill’s main advice is that you get what you pay for. Shop around and understand what you’re going to get for your money.

     

    A good building inspector should provide constructive input

    A good building inspector will be somebody who tries to educate you as you’re going along. A bad building inspector will be somebody who just turns up, says ‘that’s wrong’ and walk away. While a building inspector is only there to check what you’ve done, they should offer you alternatives.

    Site work should not be held up because of an inspection

    The building inspector is not a clerk of works and therefore is not there all of the time.

    Legally, if the building inspector has been informed that you’ve got to a particular stage, you only have to wait for 24 hours before proceeding.

    Phill explains: “If they don’t turn up, you can continue because you gave them the opportunity to visit. Councils will always visit because that’s our policy and that’s how we get insured. As I said earlier, approved inspectors may take a more risk-based approach.”

     

    Inspections fall into 8 stages

    The majority of the checks are to do with the groundworks.

    1. Commencement (preparing the files)
    2. Foundations inspection (to check ground conditions; often combined with the commencement stage)
    3. Foundations laid
    4. Oversight (to check the insulation and any re-inforcement has gone in)
    5. Damp-proof course level
    6. Drainage (to check pipes are lined and level)
    7. Occupation prior to completion (e.g. drainage check at the end of the project)
    8. Completion

     

    Builders/architects should have a good grasp of building regulations

    There are about fifteen approved documents ranging from foundations through to fire and electrics. The government has a process of only changing three of them at any one point. As the rate of change is relatively slow too, it should not be too difficult for experienced architects and builders to keep up.

    If there is a major change to any building regulations, it would be publicised in their trade magazines and they could also ask a building inspector.

    Products change much more quickly

    One of the biggest challenges a building inspector faces is keeping up with new products.

    For example, insulation can become more effective and therefore less might be needed in the construction (so it’s not just a case of checking the thickness of the insulation!).

     

    The completion certificate is not a warranty

    The most important document in this process is the completion certificate.

    This is not a warranty but states that, to the best of the inspector’s ability, the building is complete and compliant.

     

    Your completion certificate will be required when you sell your home

    Solicitors will want to see your completion certificate in order to convey your house.

    Phill says: “That’s great for the profession because you have to have that completion certificate. And you cannot sell a property without it.”

     

    Find out more

    Download the building regulations from the Planning Portal

    Follow Phill Skill on Twitter

     

    Transcript

    Download a transcript of the interview with Phill Skill

     

    Why it’s worth visiting the Potton’s Self Build Show Centre

    Regen Media is currently producing a video for Potton on the value of visiting their show centre in St Neots, Cambridgeshire.

    I know the site well having been there numerous times, but it was intriguing to hear the many reasons that people give for coming to popping in (depending on where they are in their self build project).

    However, top of the list is inspiration and that alone is a good enough reason to check out these five fully furnished homes (including the UK’s first show home constructed to Passivhaus standard).

    potton-show-centre-aerial-shot

     

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