In building construction, an expansion joint is a mid-structure separation designed to relieve stress on building materials caused by building movement induced by:
- thermal expansion and contraction caused by temperature changes
- swaying caused by wind
- seismic events
- static load deflection
- live load deflection
The joint marks a gap through all building assemblies because the joint bisects the entire structure–walls, decks, plazas, foundation floors and walls, roofs, planters, and green roofs, fire-rated demising walls and floors, and interior floors. This gap must be filled to restore the waterproofing, fireproofing, soundproofing, air barrier, roof membrane, trafficable surface, and other functions of the building elements it bisects.
Expansion joint systems are used to bridge the gap and ensure building assembly functions while accommodating expected movements.
The term “movement joint” has been widely adopted in preference as it more appropriately describes the fact that building movement results in both compression and expansion of the material installed. For example, when a structure heats up, the building materials from which it is built expand. This causes the “expansion joint” to close down, thereby compressing the joint system installed in the gap.
The above is a wall expansion joint. This structural opening bisects not only the facade but the structural building elements as well. While accommodating movement, joint materials used to fill wall expansion joints must restore the intended functions of the facade and structural building elements. These functions include: waterproofing, resisting hurricane-force wind and water, air-barrier sealing, soundproofing, and in many cases fireproofing. Additionally, because wall expansion joint materials interface with facade materials that should not be penetrated with fasteners, non-invasive anchoring is a desirable feature.
Conversely, when the temperature drops, the materials cool causing the joint gap to open. This requires the joint system to expand to follow the joint movement.
Dominion has installed and or replaced expansion joints as part of waterproofing projects including walls, plazas, parking garages, parking decks, and other surfaces in Washington, DC, Arlington, Alexandria, Fairfax, and throughout the metro DC area. In most cases, these projects have also included the installation of traffic coatings. Applications include multi-story parking garages, parking decks and ramps, footbridges and walkways, mechanical rooms, stadiums and arenas, plaza and rooftop decks, and balconies. We use top-quality expansion joint, waterproofing and coating materials that come with manufacturers’ warranties and we also provide an installation warranty on our work as well. Our work is always performed by our own crews under the supervision of a project manager who ensures safety, minimal disruption to tenants, and quality control.