BP Basics

Basics of Building Physics

This study document deals with the basics of Building Physics.

(Klick on the titles of the six parts to go to the documents or on the titles in the column at the right)



The daily use quality of a building depends to a large extend on the performance achieved with respect to indoor climate: thermal comfort, air quality, day light, artificial light, acoustics, etc. There also is a strong relation between the way these performances are achieved and the energy use of the building.

Furthermore one takes it for granted that the building structures (facade, roof) fulfill their function for many years and are not damaged by interstitial condensation or other problems. All these aspects are subject of the study of Building Physics.

Furthermore energy conservation, a careful choice of building materials and a healthy indoor climate are very important with regard to sustainability.

Building Physics bridges different knowledge domains. For this reason it is of importance for all parties involved in building: project developer, architect, consultants on structural design, building services, building contractor, etc.

Basic knowledge on Building Physics is built up step by step in six main parts and made applicable by examples from building practice.

The information in this study document is suitable for higher technical education as well as BSc-students in building sciences at universities. After studying the basics the information emains very useful as reference when making assignments and graduate projects.

For students and also for those who are working in building practice special attention is paid to rules of thumb and figures to be used, material properties, etc.

To give an entrance to the use of standards and legislation in practice, examples of the way Building Physics aspects are treated in these official documents are given. These examples comes from the Dutch situation, but since only the principles that form the bases are discussed these examples also give an entrance to European standards and standards and legislation overall.

This information in not only meant to provide the knowledge needed in education but also give a clear view how to use this knowledge in practice.

The main goal is realizing new or renovated buildings that are ‘fit for purpose’, provide a healthy living or working environment thus contributing to sustainable building.


1 Basics Heat and moisture transfer – thermal insulation

Heat, heat transport, thermal insulation

This chapter deals with the basic terms relating to heat and heat transport. The use of these terms, and their application in constructions in practice are covered in Chapter 3, ‘Heat and vapour transport in practice’.

In addition to the basic principles, this chapter also includes information on heat resistance and the effect of temperature in constructions, as well as the phenomena of heat accumulation, thermal bridges and thermal stress.

Moisture, moisture transport, condensation

This chapter deals with the basic terms relating to moisture, condensation and moisture transport in constructions and similar objects. The subject matter is illustrated using practical examples.

Heat and moisture transport in practice

Using descriptions of prototypes of constructions and practical examples, this chapter gives an overview of the most important aspects of heat and moisture transport in various real-life constructions.


2 Basics Lighting – basics – daylight – artificial lighting

For all functions of living and working, good lighting is essential. This does not just concern the amount of light required to ‘perform the task of the eye’, but also the level of visual comfort. It is especially important to prevent major differences in brightness in the field of vision. Furthermore, the lighting must be sufficiently divided or, rather, properly focussed if a certain object must be accentuated. This chapter deals with all basic variables and provides directions for dealing with daylight and artificial light.


3 Basics Thermal Comfort – Ventilation – Solar Control

Thermal Comfort

The quality of the indoor environment is about all the aspects that can influence certain sensory perceptions, or which can affect the way people function physiologically. All the factors that feature in the physical side of construction – heat, moisture, sound, light – have a role to play here. But there are also other matters, such as the purity of the indoor air, that are important. This involves the removal of combustible products (respiration), waste substances given off by machinery (copying machines) and pollution introduced into the air by building materials (formaldehyde, radon). Thermal comfort has a prominent position in this area


Ventilation with fresh outside air is necessary for good air quality inside a building, and for controlling the indoor environment during the summer. At the same time, it is important to distinguish basic ventilation from summer ventilation. Unmanaged ventilation with outside air through (opening) joints (infiltration) is undesirable as it causes draughts and unnecessary energy consumption. For that reason, this chapter also covers the air permeability of the building shell.

The stack effect, or chimney effect, plays an important part in the driving forces for natural ventilation.

Solar gain and solar control

The strength of the solar radiation that falls on the outer wall of a building can be as much as 900 W/(m², depending on the time of year and its orientation. If the radiation is able to enter the building, it will heat it up considerably. During the winter, spring and autumn this can be pleasant, and the radiation may help save energy. In the summer, however, it can lead to unwanted increases in temperature.


4 Basics Energy – Sustainability

Energy and energy performance

Approximately 40% of the total yearly energy consumption in the Netherlands is used in buildings. The building practice has a great need for predicting and calculating the various elements of energy use of buildings. This makes sense, because besides the environmental need to reduce energy use, energy costs money.

Using less energy will result in money-saving. This means that when a company or consumer is considering the purchase of a new boiler or lighting, they should also consider the energy use of this device. The financial investment in such a device, after all, goes beyond the initial investment: the energy itself also has to be paid each year. And the aggregate costs of this over the years could be even higher than the purchase price.

Sustainable construction

Sustainable construction means that homes, buildings and other structures are developed and used with respect for people and the environment. Sustainable construction does not just concern energy-saving in homes and buildings, but also includes:

  • the use of sustainable materials with take account of the environment and the health of residents and users;
  • a healthy indoor environment due to good ventilation which prevents moist, mould and accumulation of hazardous substances.
  • sustainable demolition, where materials can be used again (reuse and recycling);
  • responsible use of water;
  • respect for the environment;
  • prevent raw materials for construction from being

Sustainable construction is therefore a very broad term.


5 Basics Acoustics


In this chapter, the basic principles in relation to sound come up for discussion: what is sound, how do people experience sound, how does sound absorption work. We also discuss how the sound situation in spaces can be evaluated and how to deal with this in the design.

Sound insulation and sound proofing

This chapter discusses sound insulation and sound proofing between rooms and between the inside and outside of rooms (facade sound proofing). We explain how sound insulation can be calculated and how this can be measured in practice and in the laboratory.

Applied sound insulation

During the design process the architect or advisor will need design tools on the basis of which estimates can be made of the sound insulation to be achieved for the structure, without having to perform ‘complicated’ calculations. This chapter describes a number of rules of thumb that can be used to make a quick estimate. A number of things must always be checked or measured later in the design process.


6 Basics Fire Safety

In order to be able to construct fireproof buildings and to use buildings safely, first it has to be determined what ‘safe’ is.

Constructing buildings ‘even more safe’ is not always achievable. Limiting factors can be the costs involved, but also the ease of use, flexibility and durability. What, then, is sufficiently safe and which measures must be taken to ensure this? Which ones are worth considering and which go ‘too far’? After all, fire hazards are always present in buildings, leaving aside unused and therefore empty bunkers. The trick is to curtail these hazards sufficiently.


Tables and formulas

To complete this serie Basics of Building Physics a last document is available gathering figures etc. to be used with calculations.