Water permeability of masonry walls

Abstract

Foreword When the wall of a house exposed to wind-driven rains allows dampness to penetrate to the interior, damage to the interior finish may be sufficient to require its replacement, a matter of considerable expense. Accordingly, there is great interest on the part of builder and owner in methods of constructing walls which wUl be resistant to the penetration of rain and in methods of "waterproofing" existing walls. An extensive investigation of the rain penetration of masonry construction is in progress at the request of and in cooperation with numerous Federal agencies. This paper gives the results obtained to date. Because of the many kinds and qualities of masonry materials and varieties of design, and the lack of a definite measure of the performance of a wall with respect to rain penetration, the study must be very comprehensive, and the results cannot be adequately summarized in a few words. Of the many factors, worlcmanship is the most important single one. However, attention to many other factors will assist greatly in securing good results. Existing walls may be effectively "waterproofed", but the cost and success of the treatment depend on many factors discussed in detail in this paper.

Factors Affecting Bond Strength and Resistance to Moisture Penetration of Brick Masonry

“…Panels instances with no attempt to obtain an were cured after construction under con-air pressure difference across the wall trolled conditions (70 F, 50 per cent (8); in others the water spray has been relative humidity) for two weeks before accompanied by an air pressure differthe leakage test was made. Bond strength ence across the test wall (9). Air pressure tests were made two weeks after the and wetting have been combined to leakage test.…”

American standard building code requirements for masonry

“…His original specification was written around the description of the : "A" workmanship given in Building Materials and Structures Report n BMS7 [27] and his service included continuous supervision of the masons b} T qualified inspectors. The contractor reported after some n months that brick masonry could not be commercially laid without some degree of furrowing of the bed joint.…”

Impact of different water penetration criteria and cavity ventilation rates on the risk of mold growth in timber frame walls with brick veneer cladding

“…As a general maintenance scheme in Nordic countries, repointing of clay brick masonry is done after 40-50 years from erection to reduce water penetration through the masonry. Further, repointing is often claimed to prevent water ingress [4,5] and avert internal dampness [6]. However, there is a need to quantify better the impact of repointing on water penetration, which is an important factor in hygrothermal analyses.…”

“…The criterion is dependent on the moisture content of masonry, stating that water penetration starts when the water content level is above 90% saturation capacity; afterward, approximately 3.8% of the deposited rain is considered to penetrate the facade. Implementing the ASHRAE standard results in a more continuous pattern of cumulative penetration, whereas a more differentiated moisture load pattern is obtained when the KS criterion is used [4].…”