wall

Investing in insulation is a good way to reduce energy consumption in the home. The homeowner must determine where adding insulation will be most cost effective. Attics are usually the place to start, followed by floors and walls. Since there is a wide variety of material on the market, thedo-it-yourselfer must choose carefully and install them with proper regard for ventilation and vapour barriers. Even if the work is performed by a contractor, the informed homeowner will benefit by his knowledge of materials and procedures.

A transient simulation method TRATMO with applications to the analysis of the hygrothermal behaviour of timber frame constructions with additional thermal insulation is discussed. This method makes it possible to evaluate the hygrothermal behaviour with respect to risks of mouldering since it gives simultaneous information on moisture content and temperature at certain sections of the construction. Based on the computer simulations and experiments a number of practical aspects to be considered in additional thermal insulation of timber frame constructions are introduced.

This paper discusses the thermal effects of air flows, and some aspects of the influence of moisture and moisture transfer on the thermal performance of a structure. Mathematical and physical modelling of simultaneous coupled heat and mass transfer in porous materials based on the volume averaging technique has been used to analyze these phenomena.

Discusses control of condensation, and moisture transfer through walls. Various air pressure barriers are suggested to control leakage. One-, two- and three-stage joint methods of wall construction are compared.

Test structures were constructed near Madison, Wis, USA and Gulfport, Miss, USA for exposure of eight types of insulated wall panels at controlled indoor conditions and typical outdoor weather conditions. Panels were instrumented with moisture sensors and tested without and with penetrations (electrical outlets) in the indoor surface. Continuous internal vapour barriers effectively prevented cold weather condensation in all panels. Installation of an electrical outlet changed moisture patterns in both the cold winter climate and the hot, humid summer climate.

Presents the conclusions of several field studies carried out in retrofitted houses in the USA and compares them with predictions from models.

Measurements reported in this paper demonstrate the increase in heat transfer due to convective air flow that can occur in wood-frame walls containing air-permeable mineral wool insulation with air spaces in contact with both sides. The effect of this air interchange between the air spaces increases with increasing temperature difference, air space height and air permeability of the insulation. Use of mid-height blocking and higher density insulation thus resulted in some reduction in the heat flow through the insulation, although convective effects were still significant.

The effect of ventilation in the space between a main wall and an exterior siding is examined with respect to reducing the building's cooling load. The buoyant force of the air in the space is considered as the motive force of air flow and the effect is treated as a problem of simultaneous heat and mass-transfer. A simulation program of heat and air flows in a wall has been developed using laminar flow theory, and its validity is examined by thecomparison of the simulation results with a weather exposed full-scale model test.

Buildings in cold climates must provide an indoor environment that is markedly different from that outdoors. The materials and components of the exterior envelope are subjected to large variations in conditions and greater demands are placed on the indoor environmental control system. Air pressure differences across building elements are augmented by buoyancy forces that influence air movement and indoor air quality. The potential for moisture condensation on and within the envelope is increased as is the danger of freezing in liquid systems.

Includes papers on pitched roofs, flat roofs, wall construction, window and door joints, and weathertightness and water penetration of buildings. The focus is mainly on water penetration but air infiltration and ventilation are also discussed.