Planning consent for eco extension

Earlier this month we gained planning consent for a new single storey extension to a previously converted threshing barn in North Devon.

The design incorporates strategies for sustainability, aiming to reduce energy consumption during construction and throughout the lifetime of the building. We have decided to use materials with a low embodied energy: the structure will be timber framed, clad with lime rendered wood fibre boards and locally sourced timber cladding. We are also looking to specify insulation levels which are better than the minimum required for building regulations, so as to improve the performance of the building for years to come.

We are looking forward to developing the detailed design as we work towards getting the project on site.

Learn more about my other residential and eco projects.

How my practice has changed since Covid 19

Since the Covid 19 pandemic, many businesses have needed to adapt to new ways of working, in order to meet government legislation and ensure that customers remain safe and healthy when they undertake essential work. This process of change has led to new discoveries and ways of working which are likely to remain well after the pandemic is over. I thought I would share a few changes I have made to my practice in the last 3 months.

More collaborative working

Virtual meetings have become a new phenomenon, and they have proved to be very effective both in terms of meeting up with clients on a more regular basis, and collaborating with other members of the design team, for example structural engineers, where previously a pre-planned and long distance journey might be required. It is no longer necessary to crowd around one computer or set of printed drawings to discuss the project. Instead the project information can be shared with the group to be viewed together.

Improved visualisations for clients

The challenge for most projects is to help the client visualise how the design will look in real life, both during the design process and before construction when the design is finished. I prepare most of my designs on a 3D modelling software called Revit, and I have discovered that it is possible to share this model with clients so that they are able to view the design from their own computer or on their tablet as it develops. It is possible to “walk-through” building, export views and comment on parts of the design which need changing.

Also during the lock-down I have been improving my 3D rendering skills using an external software package called Blender. This allows my basic model to produce photo-realistic images of the interior and exterior of the building, incorporating realistic lighting, materials and textures to take the design visualisations to the next level.

Glebe barn render

Leigh cottage render

Safe site visits

I now keep site meetings to an absolute minimum, but sometimes they are essential to ensure that the design progresses in an effective manner. At the beginning of jobs I always undertake a measured site survey to analyse the site and gather information about any project, but careful planning is required to make sure this is as safe for all of us. Before the visit I will coordinate with the client about the planned measure-up to discuss how we will ensure social distancing measures and the steps taken to disinfect tools and equipment. The measure-up will be postponed if either party is isolating, shielding or simply does not feel comfortable with it at that moment in time.

Rather than meeting all new potential clients on site, as a first step I will now be arranging virtual meetings to discuss all possible new jobs. During this meetup I will try to gather as much information as possible for me to prepare a quote for the work, so we will discuss information about the site and the client's requirements for the project. There is no obligation to proceed any further than an initial meeting, so if you are unsure about whether you need assistance form an architect, please do not hesitate to get in touch.

Design for energy efficiency: airtightness

As we become increasingly conscious of our impact on the planet and our local environment, it’s essential that our built environment is constructed for minimal energy consumption. Previously we touched on Passivhaus, a higher quality of design and construction with a clearly defined standard for energy use in all building typologies. In this post we’ll explore airtightness, a critical requirement of achieving Passivhaus certification and why an airtight home has significant implications for a building’s occupants and the environment.

What is airtight construction?

In a nutshell, airtight construction means that the building envelope is draught-free. This is achieved by implementing an airtightness barrier which must be continuous and thoroughly joined across all junctions of the building envelope to form a complete loop. This continuous airtightness loop comprises a combination of interconnected materials and flexible sealed joints to ensure the building envelope has no unplanned gaps that would otherwise allow air to leak in or out of a building.

Why should we consider airtightness in our buildings?

The majority of the UK’s housing stock loses a lot of heat; approximately 20-30% of the heat generated to warm our homes leaks through the building fabric. This can be down to poor design, poor quality of building or mistakes during construction. Whatever the reason may have been in the past, we should strive to develop our built environment to be as energy efficient as possible. By building airtight, ventilation becomes an important consideration for the buildings’ occupants. Fresh air is brought into the building mechanically whilst stale air is exhausted outside. A heat exchanger warms up the incoming fresh air from the exhausted stale air without the two streams ever mixing. Mechanical ventilation is a very important consideration for airtight design and is a topic we will explore in a future post.

The benefits of airtight design

The airtightness of a building has important implications for our planet and the building’s inhabitants. An airtight building results insignificantly reduced energy demand & energy bills, reduced CO2 emissions, an increased level of comfort, and an overall healthier living environment. By achieving good levels of airtightness, you also achieve structural protection from mould growth, moisture, damp, rot, and condensation which in turn reduces maintenance required over a buildings’ lifetime.

How do we achieve airtight construction?

A clear airtight strategy is required to achieve a draught-free building envelope. An architect can help plan for airtightness during early stages of the design process by planning where all air penetrations should occur and detailing how the joints between materials are sealed. Early planning is critical to ensure careful consideration has been given for the various junctions that occur throughout a building. The airtightness of a building will be checked three times during the construction process to ensure the desired performance target is on track to be achieved. The first test is taken when the building has been made air tight. The next test is taken when all services have been installed. The final test is on completion. During these tests, any defects can be identified and resolved before construction is completed.

Project Focus

In the design of Wellington Lane, smartply sheathing was used to create the primary airtightness barrier. Airtightness has been engineered into this sheathing panel and the special surfacing provides an integrated vapour barrier with consistently high vapour resistance over the entire surface. The special coating also provides a smooth durable surface for excellent bonding of airtight tape at panel joints allowing the airtightness barrier to be continuous and joined up throughout the building. A photo taken during construction of Wellington Lane shows the airtightness barrier is located on the interior side of the wall. This allows the insulation and building envelope to breathe and wick any moisture away whilst keeping the interior spaces comfortable and airtight.