Where is all the timber needed to construct more Passivhaus buildings going to come from?

This was a question (paraphrased) asked by a person at a recent presentation I gave about the international Passivhaus Standard. They were clearly under the impression that it was easier / better / necessary to use a timber frame construction system to build to the standard.

I shouldn’t have been surprised since I was presenting on behalf of Architype, where I work. Architype are leaders in designing Passivhaus buildings and timber buildings, so the majority of the Passivhaus buildings I presented were timber construction.

It is a common misconception that timber is best for Passivhaus construction.

Ironically, there is also a misconception that ‘natural materials’ are not suitable for Passivhaus, therefore ruling out the use of timber.

Neither is true!

The international Passivhaus Standard is a performance standard: many different construction systems are possible.

041 Passivhaus Construction Not Just Timber
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This is a Passivhaus Basics blog post that gives an overview of a specific aspect of the Passivhaus Standard.

Thermal bridges (sometimes referred to as “cold bridges”) in the building envelope have a measurable impact on energy efficiency and thermal comfort. The impact can be relatively low on buildings that are not very well insulated. However, with buildings that are well insulated and energy efficient, the relative impact of thermal bridging is significant.

Building regulations and codes are now starting to recognise this and in some places, it is required or recommended that thermal bridging be minimised.

The Passivhaus Standard recognises the importance of thermal bridges and the significant impact they can have on the high-performance Passivhaus building envelope. The Passivhaus Standard requires a continuous thermal envelope: this means thermal bridge free construction.

This blog post answers the following questions:

  • What is a thermal bridge?
  • What are the different types of thermal bridges?
  • Why are thermal bridges a problem?
  • What is thermal bridge free construction?

The Passivhaus Standard requires thermal bridge free construction to ensure a robust high-quality building envelope that delivers radical energy efficiency and exceptional comfort.

What is Thermal Bridge Free Construction
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This is a Passivhaus Basics blog post that gives an overview of a specific aspect of the Passivhaus Standard.

The Passivhaus Standard requires a fabric first approach and a high-performance thermal envelope. Not only does the thermal envelope need to be high performance, it also needs to have an efficient surface area in relation to the size of the building. The thermal envelope is, after all, the main area through which a Passivhaus building can lose heat.

The Heat Loss Form Factor is one way of measuring the efficiency of the surface area of the thermal envelope.

The Heat Loss Form Factor is the ratio of thermal envelope surface area to the treated floor area (TFA). This is effectively the ratio of surface area that can lose heat (the thermal envelope) to the floor area that gets heated (TFA).

In other words, the Heat Loss Form Factor is a useful measure of the compactness of a building. And the more compact a building is, the easier it is to be energy efficient. Conversely, the less compact a building is, the more insulation will be required for the building to be energy efficient.

The Heat Loss Form Factor is a measure of compactness and an indication of how much insulation will be required to achieve the Passivhaus Standard.

Passivhaus Heat Loss Form Factor

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This is a Passivhaus Basics blog post that gives an overview of a specific aspect of the Passivhaus Standard.

In passivhaus design and construction, there are frequent references to the “building envelope” and the “thermal envelope.” Neither are exclusive to the Passivhaus Standard, but both are important aspects of the standard.

A building envelope is the physical separators between the conditioned and unconditioned environment of a building including the resistance to air, water, heat, light, and noise transfer. The three basic elements of a building envelope area weather barrier, air barrier, and thermal barrier. [Wikipedia]

In simple terms, this means that the building envelope is made up of the walls, floors, roofs (or ceilings), windows and doors that separate the inside from the outside. The passivhaus building envelope is also made up of these elements, but there are some key aspects that make the passivhaus building envelope distinct.

The passivhaus building envelope requires a high-performance thermal envelope, it must be continuous and it is key to the fabric first approach.

028 What is the Passivhaus Building Envelope
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What is the fundamental purpose of a building?

Buildings serve several needs of society – primarily as shelter from weather, security, living space, privacy, to store belongings, and to comfortably live and work. A building as a shelter represents a physical division of the human habitat (a place of comfort and safety) and the outside (a place that at times may be harsh and harmful).
Wikipedia

As you can see, comfort is fundamental to the purpose of a building. So why do we find it so hard to ensure our buildings are actually comfortable? Why does our ‘world-class’ architecture still fail to provide comfortable buildings to live, work, learn and play in? (Besides using far too much energy and emitting far too much CO2!)

The Passivhaus Standard is known as the world’s foremost building energy efficiency standard. And it is that, but it is also a comfort standard. After all, what is the point of a building being energy efficient (or low carbon for that matter) if it compromises the functionality and comfort of the people who use the building? Passivhaus buildings provide exemplary comfort for the occupants by maintaining a healthy comfortable temperature, by being quiet, by having fresh air and by being draught-free.

Comfort is a reason to Love Passivhaus!

019 Love Passivhaus Comfort
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