wood frame

This report presents the results of air leakage tests on polyethylene membranes installed in a frame wall. The results would be useful in evaluating the methods commonly used for installing such a component.

Describes in detail a computer-based technique for predicting the risk of condensation occurring in building structures. The technique not only indicates the position at which condensation is likely to occur, but also puts a figure on the risk of decay in timber within the structure. In the case of ventilated roofs or walls it gives the minimum sizes for ventilation openings.

Describes construction of timber-frame housing to high level of airtightness. A target level of 0.4 ach at 50 Pa was set. At this level, total air control provides an extremely high level of comfort by eliminating draughts and by supplying precise amounts of fresh air where required. An air and vapour barrier was installed within the house structure.

Outlines the fundamentals of insulation and airtightness, proper air quality, and ventilation. Presents details of design and construction for walls, roofs, foundations, windows, and air-vapour barriers, as well as discussions of ventilation systems, heating systems, appliances and methods of testing and evaluation. One of the appendices gives weather data for selected US and Canadian cities. Aims to be accessible to the interested layperson or homeowner.

For optimum building design it is of importance to investigate the comfort and the energy conservation obtained with different types of ventilation systems and levels of airtightness of buildings. This could be achieved by aid of computer models based on full-scale and model measurements. In order to obtain experimental data as input data to such a computer model, an experimental, detached one-family house has been built near to Gothenburg on the Swedish west coast.

Natural and forced ventilation are directly and indirectly influenced by the pressure distribution around a building. Results of full-scale pressure measurements on a typical Swedish timber house are presented. The rate of air infiltration has been calculated by employing the values obtained from full-scale pressure distribution, air leakage characteristics and temperature differences. The results are compared with the actual ventilation obtained from tracer gas measurements.

A previous paper analysed a mathematical model of a non-condensing cavity. This paper extends the analysis of the first paper to analyse the seasonal moisture behaviour of a condensing building cavity. Climate statistics are used to calculate the duration of the winter wet-up period, and a rate of condensation formula is integrated to give total winter condensation. Although engineering design calculations cannot yet be attempted, some illustrative examples are given based on field data. The results give preliminary verification of the model analysed in both papers.

This paper, the first of two, presents a conceptual model of moisture concentrations in a building cavity. The model is comprehensive and general considering air infiltration, vapour diffusion and material hygroscopicity under non-steady state conditions. The resulting linearised coupled differential equations are analytically solved to study the case of long term cavity moisture behaviour. Dimensionless parameters and algebraic formulae are presented describing all important moisture performance parameters for a non-condensing cavity.

Air leaks which can bypass attic insulation in US wood framed houses are identified. Examples of heat loss paths include gaps at the entry of plumbing, heating or cooling ducts and electrics gaps around flues, and trapdoors. Remedial measures discussed include stuffing gaps with fibreglass, weatherstripping, taping polythene sheet over gaps, sealing and insulating ducts, and covering ceiling fan vents during the winter.

States that the higher internal humidity and lower structural temperatures in UK timber frame houses, as compared to the US and central Europe increases the risk of interstitial condensation. Condensation risk has also increased in all countries because of energy conservation measures and changes in heating patterns, occupation density and moisture production. Gives recommendations for the prevention of interstitial condensation.