Describes the results of a major study to find out whether or not wall insulation installed without a vapour barrier causes an increased risk of moisture damage within walls. The exterior walls of 96 homes in Portland, Oregon were opened. Presents results of field and laboratory tests which show the absence of indications of moisture damage. Gives data on shrinkage and settling of insulation and results of air leakage measurements by fan pressurization tests. Concludes that the addition of wallinsulation without a vapour barrier does not cause moisture damage in existing homes.
Sets out in general terms the design principles for avoiding condensation in roofs, pitched and flat. Recommends providing arain shield permeable to water vapour, a vapour barrier on thewarm side of the structure and in roofs with air spaces to ventilate the air space or blow dry air into the roof space.Discusses application of these to particular types of roofs.
Gives instructions for constructing a super-insulated house. Describes installing insulation, vapour barriers, shutters and an air-to-air heat exchangers. Outlines ways in which heat islost from a house and the problems of conventional structures.
Suggests methods of conserving energy in new houses. Gives detailed instructions for installing vapour barrier; constructing double stud wall, insulating walls and windows. Also discusses moisture problems and the use of an air-to-air heat exchanger. Outlines other methods of saving energy and waysof refitting an older house.NOTES An updated second edition has been published as "Energy efficient housing - a prairie approach" abstract no.643.
Calculations of water vapour flow through walls and ceilings are frequently based on the permeability of building materials and implicitly assume that most of the vapour transport takes place by diffusion. Finds that this model is generally inval
Reviews the requirement in building regulations for cavity barriers in roofs. States need for providing ventilation in the cavities of certain forms of roof construction,particularly those with a continuous waterproof vapour barrier to avoid moisture build-up. Examines how adequate air movement can be provided in both new and existing flat roof voids, designed with or having installed cavity barriers.
Describes the influence on heat resistance of an insulated wall of workmanship and forced convection. Compares experimental investigations on cross-bar walls with calculated values. Examples show the influence on heat resistance of insulation installation, air-flow along the insulation and air-flow through the insulation. Concludes that air-tightness of the vapour barrier and partly of the inside board are of great importance.
Discusses reasons for making buildings air-tight and the requirements of the swedish building code. Gives examples of design solutions for detached houses and construction details for applying an internal vapour barrier consisting of a polythene sheet. Describes application to seven bungalows, resulting in air change per hour of 0.67 to 0.86. Subsequent measurements of ventilation and air velocity showed that in mechanically ventilated airtight houses the flow of ventilation air can be accurately controlled by the exhaust fan.
Analyses the problem of air management in energy conserving passive solar houses and discusses cost effectiveness of various alternative scheme. Use of polythene sheeting to form anair-tight membrane aims to reduce uncontrolled ventilation rate to 0.05 air changes per hour. Discusses problem of indoor air pollution and suggests adding venting windows and air-to-air heat exchangers. The need for internal air circulation is answered by ceiling fans or a central forced air system.
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