The Effect of Oriented Strand Board Substrate Treatments on the Adhesion of Cement Adhesives and Coatings

Abstract

Thanks to its properties, wood as a building material has unbelievable potential. It simultaneously provides answers to frequently discussed questions concerning the renewability of resources and the energy performance of buildings. The material most frequently used as sheathing for timber structures is planar large-format oriented strand board (OSB). The unfavourable effects of the weather on unprotected wood and timber products can cause changes to the mechanical and chemical properties of the wood, and if unchecked can do irreversible damage. It is therefore always necessary to apply additional surface finishes to sheathing. In the case of peripheral walls, these surface finishes usually comprise an outer thermal insulation system, while in the case of internal surfaces, extra sheathing made from board materials is added via adhesion or mechanical attachment. It is possible to glue extra layers directly onto OSB, but only if suitable adhesives are used, and the range of products is limited. The research described in this article focuses on the treatment of OSB substrate so that it is possible to employ cement adhesives that are commonly used for the gluing of thermal insulation but which cannot normally be used on an untreated base without the danger of adhesion loss. The research concerns a comparison of test specimens with various kinds of penetrative coating or bonding primer applied under predefined conditions and subjected to different forms of applied loading. The contribution contains a definition of the substrate material, test specimens, test methods and a selection of 5 different types of material for the surface treatment of the test specimens. Tables comparing the influence of the individual finishes on the adhesion itself are included in the outputs. The conclusion contains the test results as well as a presentation of the effects of individual treatments, and potential further research is suggested. The results are of benefit to subjects involved in the preparation and realization of construction work that deal not only with timber structures in particular but also with the general use of OSB structures as a part of the building envelope.Thanks to its properties, wood as a building material has unbelievable potential. It simultaneously provides answers to frequently discussed questions concerning the renewability of resources and the energy performance of buildings. The material most frequently used as sheathing for timber structures is planar large-format oriented strand board (OSB). The unfavourable effects of the weather on unprotected wood and timber products can cause changes to the mechanical and chemical properties of the wood, and if unchecked can do irreversible damage. It is therefore always necessary to apply additional surface finishes to sheathing. In the case of peripheral walls, these surface finishes usually comprise an outer thermal insulation system, while in the case of internal surfaces, extra sheathing made from board materials is added via adhesion or mechanical attachment. It is possible to glue extra layers directly onto OSB, but only if suitable adhesives are used, and the range of products is limited. The research described in this article focuses on the treatment of OSB substrate so that it is possible to employ cement adhesives that are commonly used for the gluing of thermal insulation but which cannot normally be used on an untreated base without the danger of adhesion loss. The research concerns a comparison of test specimens with various kinds of penetrative coating or bonding primer applied under predefined conditions and subjected to different forms of applied loading. The contribution contains a definition of the substrate material, test specimens, test methods and a selection of 5 different types of material for the surface treatment of the test specimens. Tables comparing the influence of the individual finishes on the adhesion itself are included in the outputs. The conclusion contains the test results as well as a presentation of the effects of individual treatments, and potential further research is suggested. The results are of benefit to subjects involved in the preparation and realization of construction work that deal not only with timber structures in particular but also with the general use of OSB structures as a part of the building envelope.