joint

Measurements made in Finland have shown that the airtightness of many small houses is lower then the level of requirements specified in Sweden. States that the most important areas for sealing up external walls in concrete structures are the joints in the internal shell, the joints between concrete and timber structures, and the joints between door and window frames. All these areas can be made airtight by using appropriate materials and construction methods. In general, the air tightness of small concrete houseshas been found to be good and to comply with the specified requirements.

Caulks and sealants are used to fill and seal joints, in order to prevent draughts and the intrusion of rain and dust. There are two types of joints; non-working joints in which there is little or no movement of the joined parts, and working joints which are designed to allow movement. Discusses for each type of joint, factors to consider when selecting a sealant and suitable types of material.

It has been shown by Bankvall that forced convection reduces the efficiency of thermal insulation considerably. The reductions can become drastic if the inner skin is not airtight. The leakage around a switch or junction box issufficient. The material in the windproofing skin must be sufficiently impermeable. If complicated joints are to be avoided it must retain its dimensions in varying humidity. If the inner skin is not tight caulking or taping the joints in a plasterboard skin halves the leakage.

In order to reduce heating energy consumption, single glazed windows are commonly replaced by double glazing and joints tightened in Danish dwellings. Reports investigation of the influence of such tightening of dwellings on the indoor climate. 25 tightened and 25 not-tightened identical flats were investigated. Finds an improvement in thermal climate and a significant reduction in heat consumption in the retrofitted flats. Finds absolute humidity of indoor air was significantly higher in improved flats, probably due to reduced ventilation.

Reports study of wind and rain over fifteen years and gives table of results. Reports measurements of wind pressure and driving rain on buildings. Discusses laboratory measurements of the tightness of facade elements under pressures of up to 50 Pa. and with temperature differences of -40 to +30 deg.C. across the facade. Describes pressurization of buildings and gives results of measurements in test dwellings. Discusses movement of joints in buildings and describes measurement of this movement.< Discusses permeability of both flat and sloping roofs.

Reviews results of tests carried out during a joint industry/university project. Discusses characteristics of single and two-component foam, airtightness, condensation and safety regulations since polyurethane foam contains isocyanates. Diagram illustrates typical cross-section through window frame under normal conditions and when conditioned at 15 deg. C and 65% R.H.

The conduction of sound through the gap between window and wall depends on the width of the gap. This width also determines the air leakage, suggesting that air leakage might be measured by an acoustic method. Notes method requires that cracks are relatively large and have fewer than three kinks. Reports measurements in a wind tunnel of air flow through crack models made from aluminium and compares results with theory. Finds empirical expression relating pressure difference to air flow and gives graphs of results.

Discusses masonry walls in relation to the air tightness of buildings. Considers mainly panel walls constructed of concrete blocks. States that in general such walls are very leaky, due mainly to shrinkage of the wall itself and deformation of the surrounding structure. Discusses the addition of insulation to wall, sealing of joints around window frames and at the edge of the floor slab. Gives diagrams showing details of building construction.