Author: Lucy Cowell

  • HPH073 : How Alterations to Period Properties Affect Performance – with Richard Oxley from Oxley Conservation

    HPH073 : How Alterations to Period Properties Affect Performance – with Richard Oxley from Oxley Conservation

    Richard Oxley from Oxley Conservation explains why understanding an old house is such a vital first step to take before upgrading its performance.

    Richard Oxley

     

    Interview with Richard Oxley

    Richard Oxley began his professional life as a chartered surveyor. He then developed his interest in old buildings by studying for a RICS Diploma in Building Conservation and after gaining experience with a local historic building contractor, in 1997 he established Oxley Conservation.

     

    An Alteration is Something That Could Make a Change to How That Building is Used or Performs

    For the sake of energy efficiency this could mean, for example, secondary glazing or insulating the roof space, walls or underfloors.

     

    “Historic” and “Traditional” Properties are Not the Same

    The term “historic” relates to how a building is protected, with greater cultural importance being placed on buildings that are historic rather than just traditional.

    front-of-old-house

    An example of an historic building

    A Number of Areas of Performance are Considered

    These include looking at how the building copes with weather, climate, orientation, how the building is used, how much water vapour is produced, and identifying which areas are most at risk and under pressure.

     

    Understanding The Building is The Fundamental Principle to Making Alterations to a Period Property

    Without understanding the building it will not be possible to know how to respond to it. By learning about its performance and what may have significance culturally or otherwise, an informed plan can be made about how best to progress.

    Woolley Firs

    A derelict farm building at Woolley Firs

    It is Important to Make Sure You Have The Best Starting Point Before Making Alterations

    Richard believes that while people can have a pre-conceived idea of how they want the building to be, it is vital that to make sure that you understand the building and identify what works are required to put the building into good repair first, such as good rainwater management and a good roof.

    He thinks this process of learning and understanding can take a couple of years, before we can then know that the alterations will be compatible and beneficial to the building and not just fulfilling the pre-conceived idea.

     

    Some Existing Works May Need to be Undone to Improve The Building’s Performance

    A lot of Richard’s work involves undoing previous works that people have carried out that had the unintentional consequence of damaging the building. This is particularly the case where modern materials have been used in past repairs and which can cause long term damage and affect its intended performance. An example is that many modern insulation materials have impervious barriers which conflict with an older building’s need for moisture to be able to move in and out. This in turn changes how the building performs and can conceal problems of damp, mould and decay.

    Woolley Firs more thermally efficient roofThe detailing of the upgraded roof at Woolley Firs

    Opportunities Should be Seized to Improve Performance Without Having to Compromise

    Using diagnostic tools, such as air pressure tests, can help in determining problem areas. Richard believes that if the chance is there then the opportunity should be taken, for example, to improve thermal performance at a time when a roof is being stripped or an extension being built. These are therefore far more effective improvements, rather than if it had been attempted with the roof still on which will usually have to be a compromise.

    Wood fibre board is added

    The wood fibre board insulation at Woolley Firs

    Research Will Help Our Understanding of Buildings

    If an improvement is going to be made, it should be an effective improvement that is beneficial to the user and has real gains in terms of energy loss and reduction. Woolley Firs was an example of a building that had research carried out on how the different elevations were subject to warming, cooling and the elements. The results highlighted how the aspects performed differently.

    Using research and learning from mistakes will give a better scientific understanding to ensure that more informed decisions are made, and that improvements are better, more effective and do what is intended of them.

    The interior walls are plastered

    The interior is rendered with a lime plaster at Woolley Firs

    A Holistic View is Required to Understand How to Improve Performance

    Many questions need to be asked, such as: how was it constructed, is it in good condition, does anything need to be done, are there characteristics you want to maintain in future, what am I asking it to do, how has it been used, how is it being used and how is intended to be used? etc. The answers to these will help to identify where the problems are and dictate the improvements that are expected or the standard that is trying to be achieved.

    Richard notes however that it’s important to be wary of imposing modern, arbitrary standards on older buildings which can lead to conflict.

     

    Diagnostic Tools Will Identify Where to Concentrate Resources

    Richard gives an example of a National Trust property where use of air pressure testing found that 30% of heat loss was through the roof. Whilst there was some energy loss through other areas they were able to make the biggest impact by concentrating resources on repairing, insulating and re-cladding the roof, to maximise the performance of the building.

    A blower door test being carried out

     

    Get to Know Your Building Before Making Big Alterations!

    Richard emphasises how fundamental it is to understand your building first: how it was constructed, the materials that were used, are there conflicts in the performance, what works are required to get it to a good state in the first instance, how you intend to use the building, etc. This will ensure that resources are directed correctly and most effectively.

    Woolley-Firs-retrofit-finishedThe completed retrofit of Woolley Firs

    Find Out More

    Visit Oxley Conservation’s website

    Follow Oxley Conservation on Twitter

    Follow Richard Oxley on Twitter

     

    Transcript

    Download a transcript of the interview with Richard Oxley.

     

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  • HPH072 : A Radical Retrofit of an End of Terrace House – with Tim Nicholson

    HPH072 : A Radical Retrofit of an End of Terrace House – with Tim Nicholson

    Tim Nicholson reveals why he chose to retrofit rather than build new and, having selected a suitable property, what the strategy was and why. Tim has also been blogging about the experience on his website Oxford Green House.

    Tim Nicholson

     

    Interview with Tim Nicholson

    After refurbishing his previous home to be more energy-efficient Tim was intrigued to take his new home, an end of terrace property, as far as he could go.

    At the heart of this retrofit was a strategy using high levels of insulation and making the building extremely airtight.

    End of terrace ripe for retrofitBefore the retrofit

    Difficulties in Finding a Building Plot in Oxford Led Tim to Embark on a Refurbishment

    With sites being so difficult to come by in Oxford, due to limited availability and high prices, Tim decided to address some of the problems with the UK’s existing housing stock and take on a radical, energy-efficient retrofit.

    Externally Insulating the House Ensured Internal Floor Space Wasn’t Compromised

    Planning restrictions led to the decision to externally insulate the building and clad it in a new brick skin, in order to maintain the existing aesthetic. They also benefited from the thermal mass, no loss of floor space and a reduced risk of interstitial condensation.

    Proposed external insulation Neighbours objected to this proposed render finish  

    Being a Terraced Property Led to Additional Challenges

    Neighbours were concerned about the ‘step’ that would be created by the additional wall, so permission was only given to clad the rear and gable walls, with internal insulation being required for the front of the house.

     

    Laying Floor Insulation Was Ambitious and Costly

    With the existing flooring being uncomfortably cold, the decision was made to dig out the existing concrete slab and the dirt beneath it, in order to lay 20cm of polystyrene EPS insulation. They found this process to be noisy, expensive, time consuming and generated a huge amount of rubble.

    The floor slab is dug up

     

    A “Skirt” May Have Been a Better Option

    Given the challenges of breaking out the concrete slab, Tim in hindsight concedes that an insulating skirt may have been a good option. This means digging a trench down the external wall to the foundations, and laying insulation in order to insulate the walls below ground and to reduce the heat loss from the building in that area. It would not have been as efficient but would certainly have been cheaper.

     

    Renting the House Next-Door Enabled the Family to Remain on Site Throughout the Project

    It became apparent that living in the house while carrying out the refurbishment was going to have many challenges. Luckily the neighbouring house was available to rent for a time which meant they could always be there to take deliveries and ensure the site was secure.

    Ground-and-first-floor-plans

     

    The Layout of the House has Been Adapted to Suit the Needs of the Family

    While carrying out the retrofit the family also took advantage of the chance to change the layout so that it would better suit their needs. This has resulted in a more open plan area downstairs which is much lighter and uses the new stove to heat the space more efficiently.

     

    A Wood Burning Boiler Stove and Solar Thermal System Provide the Hot Water and Heating

    The property has been disconnected from the main gas supply. The wood burning boiler stove will provide the hot water and heating at times when there isn’t enough being generated by the solar hot water system.

    Solar thermal and solar PV

     

    Refurbishing Rather Than Rebuilding Was a Better Option

    With all the works taking place, and particularly given that it could be argued there wasn’t too much left of the original, knocking down and rebuilding the property could have been considered. However, being end of terrace it would have been extremely challenging with regard to the neighbouring properties.

     

    It Has Been an Expensive but Worthwhile Process

    While the works have been costly, Tim sees it as being a dual process of carrying out a high standard refurbishment and also creating an energy efficient home. Any extra investment in using the high quality products he believes is reasonable when looking at it over their lifetime.

     

    Too Much Hot Water Has Resulted in an Underfloor Heated Log Store!

    On days where there has been a lot of sunlight and not so much consumption, the large solar thermal system has continued to produce hot water to the point where it was boiling in the cylinder. Tim describes how they now divert any excess by pumping it down to their log store to help dry out the logs for winter.

     

    Tim Hopes Their Lessons Learned Will Help Others Carrying Out Similar Projects

    By sharing information on their website about the suppliers they have used, products specified, and their decision making processes, Tim hopes that anyone else doing a similar retrofit can learn from their successes, failures and experiences.

    Find Out More

    Visit Tim’s website Oxford Green House

     

    Transcript

    Download a transcript of the interview with Tim Nicholson.

     

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  • HPH071 : Open Source, Digitally Manufactured Homes – with Alastair Parvin from WikiHouse

    HPH071 : Open Source, Digitally Manufactured Homes – with Alastair Parvin from WikiHouse

    Alastair Parvin explains how WikiHouse has developed and why it is so significant when it comes to enabling more people to build affordable, high quality homes.

    alastair-parvin

     

    Interview with Alastair Parvin

     

    WikiHouse Developed From a Curiosity About Emerging Technologies

    Alastair had researched how financial capital shapes our housing and why a relatively prosperous nation should have a housing crisis of small and poor quality homes. With an interest in digital manufacturing and developments in the open source code movement, he realised the potential in these technologies being combined for the physical production of affordable houses.

     

    It is an Open Source Construction System

    3D models and cutting files form the detailed manufacturing information and are shared on the web for the benefit of anyone to download, edit and develop for free. CNC cutting is used and all the parts are named and numbered to produce a giant flat pack house.

    WikiHouse-hammer

     

    WikiHouse is Not Aimed at a Particular Market

    It is likely that initially it will be self-builders that will pick up on WikiHouse, but in the longer term Alastair’s interest has been to produce something very useful and then see just how it gets used.

     

    It is an Achievable Option for Those Wanting to Self-build

    It is likely that for an inexperienced end user it could be challenging, however there could be a whole range of companies who would be able to help with the manufacture and assembly. It could even work out to be realistic and cost effective to purchase the cutting machines if the production was going to be on a large enough scale.

     

    Predictability and Being Able to do the Work Yourself Provides Affordability

    Dispensing with the need for a contractor to construct the house will inevitably produce savings. And with costs being more accurately predicted Alastair believes it is easier to produce a realistic and more achievable budget.

     

    It is a Prototype for Future Development

    Alastair emphasises that while the WikiHouse V4.0 is of plywood construction, there is no reason why other structural sheet materials can’t be used. He is keen to see the designs and technologies being taken and improved by others for the continuing development of the system.

    WikiHouse-prototype-4

     

    Minimal Tolerances Offer an Expectation for Good Airtightness

    The accuracy of the CNC cutting process produces such tiny tolerances, just 5mm difference in length from the model to the real life V4.0, that there are expectations this should work favourably for achieving good airtightness.

     

    The Parts Being Portable is a Real Advantage

    The portability of the parts means they can be carried comparatively easily and without the need for extra kit. This also means they can be put in places which would be far less accessible to a traditional build.

     

    The System is Being Evolved to Attempt to Make it Fool-proof

    With the logistics involved being sometimes harder than actually doing the building, they are attempting to evolve the system to make it impossible to get wrong. As it is effectively a “building by numbers” process, Alastair has learned the need for suitable space and covering to lay out all the pieces of the puzzle.

    WikiHouse-stairs

     

    Designers Aren’t Redundant in This System

    Alastair believes customers will still be employing the services of designers and other local small companies and manufacturers. Thus he expects most users of the WikiHouse system to be professionals.

     

    WikiHouse V4.0 is Not a Show Home!

    Rather than being a show home, this prototype has been an experiment in public to show what can be done, and to prompt debates about our rights to build. It has been a huge learning experience and the lessons from it will be shared to aid continual development and improvement. Alastair hopes that in the future there will be WikiHouses popping up around the world, creating a living not just for themselves but also other parties. He ultimately aims that there will be a greater diversity of technologies and construction methods which can begin to address the problems of housing on a whole neighbourhood scale.

     

    Find Out More

    The WikiHouse website

    Follow Alastair Parvin on Twitter

    Watch Alastair’s 2013 Ted Talk – Architecture for the people by the people

     

    Transcript

    Download a transcript of the interview with Alastair Parvin.

     

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  • HPH070 : Can You Create an Ecological Building with Insulated Concrete Forms (ICF)? – with Jake White from Ecotecture

    HPH070 : Can You Create an Ecological Building with Insulated Concrete Forms (ICF)? – with Jake White from Ecotecture

    Jake White from Ecotecture shares the story of The Curly House, an award-winning project that was built using insulated concrete forms (ICF). He explains what an ICF is, why there are benefits in terms of speed of construction and durability, and why most concrete structures have the potential to be extremely airtight.

    Jake_White

     

    Interview with Jake White

    Jake White has been a director at Ecotecture for 10 years now.

    His interest in low energy buildings and sustainable design was brought about by a desire for improvement, having seen how bad the quality of workmanship and lack of understanding was in the “house bashing” industry.

    Curly-House-during-construction-1

     

    Concrete’s Bad Reputation is Not Always Deserved

    The manufacture of concrete and the resultant CO2 emissions often give it a bad reputation. Jake feels that given its durable, dense, long-lasting structure, this should not be the case for buildings that are designed to last generations. In producing buildings of this quality he is disconnecting his clients from the effects of fuel hikes and fuel poverty.

     

    Insulated Concrete Formwork Does Not Prevent the Benefits of Thermal Mass

    Traditionally the thermal mass of concrete has always been exposed so it will re-emit the heat at night time that has been absorbed during the day. The experience Jake has had of using the insulated concrete formwork is that there is a lag in the heat being re-emitted and thus the benefits from it last longer than the single day.

    Essentially Jake expects the temperature of the concrete core to remain stable and consistent with the interior temperature of the space.

     

    A Single Construction Method can be Best for Cost and Energy Efficiency

    This was certainly the case for the Curly House, which has a beautiful but very exposed site. Jake suspects that over time if different construction methods had been used, such as a concrete basement and timber frame, there would have been jarring against each other resulting in the airtightness being compromised.

    Concrete was deemed to be the ideal material to match the undulating forms of the building with those of the landscape.

    Curly-House-during-construction-2

     

    The Key to Insulated Concrete Formwork Longevity is a Dry Central Core

    A tanking treatment is used on top of the regular foundations to prevent moisture from rising.

     

    There are Key Features to Look for When Selecting an Insulated Concrete Formwork Product

    • The adaptability
    • The quantity of details they have and have thought through
    • The technical support

    Curly-House-(from-road)

     

    Reduce Waste by Selecting the Right Thickness of Product for the Job

    Even within a single project there are different thicknesses of concrete needed, dependent on the load they are retaining. The products are designed so that you only have to use the thickness that is required for the particular task.

    The absolute minimum width required cannot always be achieved, given the limitations and requirements of the pouring process.

     

    There is Flexibility in Terms of How Insulated Concrete Formwork can be Rendered

    Due to the excellent levels of airtightness almost any interior or exterior finish can be applied. It is one of the rare products which doesn’t need a wet plaster finish on the interior for the purpose of achieving airtightness.

     

    Great Results can be Achieved if Attention to Airtightness is Given

    Jake has seen examples of buildings using insulated concrete formwork where, even without trying, adequate levels of airtightness were achieved. With these results almost being realised by accident it wouldn’t take a great deal more effort to achieve the Passivhaus standard.

     

    Tapes and Membranes are Still Required for Windows and Doors

    For buildings that have a full insulated concrete formwork, the only areas vulnerable to air leakage are around the windows and doors so tapes and membranes need would need to be used.

    Curly-House-(from-garden)

     

    High Quality Design Requires a High Quality Contractor

    The Curly House benefited from having a contractor with lots of experience in the systems being used. There had been many challenges but the level of attention to detail and capabilities of the contractor resulted in the high quality design being reflected in the construction.

     

    Find Out More

    Visit Ecotecture’s website

    Follow Jake White on Twitter

    Matthew Cutler-Welsh from Home Style Green chats to NUDURA’s CEO Murray Snider

     

    Transcript

    Download a transcript of the interview with Jake White.

     

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