DAMPNESS IN BUILDINGS
Roman wisdom states that a fire may be stopped with water but asks with what can you stop water? Water is one of the most destructive forces faced by buildings. It needs to be eliminated by careful design, construction, and regular maintenance. Buildings generally represent the largest investment most of us make in our lives. We use buildings as investments and as a hedge against inflation. It is worth remembering that to enhance the longevity of any building, it must be maintained regularly. Some useful tips in that respect are:
•Ensure that water does not run under the building.
•For floors above the ground, ensure there are vents to facilitate air flow.
•Repaint painted surfaces before the paint coating has broken down too far.
•Ventilate the interior by opening windows.
•Do not vent showers or clothes dryers to the roof space. Ensure they vent to the outside.
Remember, buildings are constructed to provide comfort against the elements of nature. The buildings must be designed and built to resist natural forces of degradation. From the time that a building is completed, it is on the slow downward path of destruction, usually at an infinitesimal rate. But that rate will depend on how well it is cared for. It is that prudent intervention of planned maintenance which gives building owners the optimum return on their investment.
As a harsh assessment of the situation, you could say that all built infrastructure (including buildings) is waste in transit.
Thursday, February 10, 2011
Noisy classrooms
Noise levels in classrooms are distressing preschool children
The problem of noisy classrooms is widespread amongst schools, affecting children of all ages as well as teachers.
With offending buildings it can usually be shown that it is a problem by calculating the reverberation time, as this is often the main problem. It is then a case of proposing some judicious changes by way of introducing some soft furnishings and possibly some changes to floor, wall and/or ceiling surfaces.
New problems often arise from “echo” nuisance experienced in recently refurbished rooms. This produces discomfort and some degree of irritability affecting occupants due to noise characteristics of the rooms.
A good approach is to analyse likely reverberation time of normal speech within classrooms. The value in seconds obtained from such an analysis indicates the time taken for sound to decay a level of 60 decibels (dB). This is a standard method of measuring sound characteristics within built spaces. For many classrooms, the desirable reverberation time is about 0.7 - 1.0 second. The actual calculated value for some rooms we have seen due to the surface materials used is 1.45 seconds, almost twice the optimum value. Such a result is consistent with the reported difficulties experienced by occupants, and of the types of interior surface finishes used in many classrooms.
We have also observed new refurbishment work that has produced considerable noise transfer from the floor of the upper levels. Typically in these cases, before the building work commenced there were acoustic ceiling tiles, and they are replaced with ceiling finishes of smooth plaster-board. The perception of the increased noise from the upper levels is often consistent with the change of ceiling lining type.
Often the answer for acceptable noise levels in classrooms is the judicious selection and use of floor, wall and ceiling surfaces.
The problem of noisy classrooms is widespread amongst schools, affecting children of all ages as well as teachers.
With offending buildings it can usually be shown that it is a problem by calculating the reverberation time, as this is often the main problem. It is then a case of proposing some judicious changes by way of introducing some soft furnishings and possibly some changes to floor, wall and/or ceiling surfaces.
New problems often arise from “echo” nuisance experienced in recently refurbished rooms. This produces discomfort and some degree of irritability affecting occupants due to noise characteristics of the rooms.
A good approach is to analyse likely reverberation time of normal speech within classrooms. The value in seconds obtained from such an analysis indicates the time taken for sound to decay a level of 60 decibels (dB). This is a standard method of measuring sound characteristics within built spaces. For many classrooms, the desirable reverberation time is about 0.7 - 1.0 second. The actual calculated value for some rooms we have seen due to the surface materials used is 1.45 seconds, almost twice the optimum value. Such a result is consistent with the reported difficulties experienced by occupants, and of the types of interior surface finishes used in many classrooms.
We have also observed new refurbishment work that has produced considerable noise transfer from the floor of the upper levels. Typically in these cases, before the building work commenced there were acoustic ceiling tiles, and they are replaced with ceiling finishes of smooth plaster-board. The perception of the increased noise from the upper levels is often consistent with the change of ceiling lining type.
Often the answer for acceptable noise levels in classrooms is the judicious selection and use of floor, wall and ceiling surfaces.
Flooding of properties
Apart from the major flood events around the world which continue to hit the media headlines, the matter of overland flow from neighbouring properties continues to be a vexing problem in all towns and cities. Constantly many areas are put to the test in that respect. At the time, there is often general acceptance of the view that flooding is inevitable. However, in cases we are called in to advise on, the problems generally result from identifiable short-falls in meeting acceptable construction details.
It is important to keep in mind that all drainage systems require a secondary overland flow path to cope with the more extreme storms which cannot be designed against. Having a clear understanding of the location and form of that flow path is important to ensure that it is not dammed by such things as fences, buildings or built-up gardens.
It needs to be kept in mind that landscaping can lead to additional problems of flooding. We see many cases where ground and pavement levels are built up too high, so that water is then able to enter buildings.
It is important to keep in mind that all drainage systems require a secondary overland flow path to cope with the more extreme storms which cannot be designed against. Having a clear understanding of the location and form of that flow path is important to ensure that it is not dammed by such things as fences, buildings or built-up gardens.
It needs to be kept in mind that landscaping can lead to additional problems of flooding. We see many cases where ground and pavement levels are built up too high, so that water is then able to enter buildings.
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