Bonded vs. Unbonded Hardscape Systems
When designing a hardscape, selecting the appropriate installation method is essential for long-term performance. Two common approaches are bonded and unbonded systems, each offering distinct characteristics suited to different applications.
Understanding Bonded and Unbonded Systems
Bonded Hardscape Systems
A bonded system consists of pavers that are securely adhered to a stabilized bedding layer and base, creating a cohesive structure. This installation method utilizes a polymer-enhanced thin set, such as ROMEX ADHESION ELUTRIANT, to affix pavers to the underlying layer. The bedding layer often consists of ROMEX TRASS BED, a material designed to provide stability while maintaining permeability. Jointing compounds such as ROMEX ECOFINE complete the system, locking in the joints while allowing for water drainage.
Bonded systems do not rely on interlock or the aspect ratio of the pavers for stability. Instead, the bedding system provides structural integrity, preventing movement and ensuring a secure surface. This method is often used in applications requiring a fixed, durable alignment.
Unbonded Hardscape Systems
An unbonded system allows for a flexible structure where pavers rest on a compacted, loose bedding layer, typically composed of fine gravel or sand. Instead of being adhered to the base, the pavers remain in place through interlock, which utilizes the shape and pattern of the pavers to create a stable surface. The design of the individual pavers and their arrangement help distribute forces and limit shifting. Jointing options in unbonded systems include traditional polymeric sands or permeable options like ROMEX FUGENSAND + D7000 and ROMEX FLEX JOINT.
This method allows for slight movement of the pavers, which can be a consideration in some climates and site conditions. Unbonded installations can also provide adaptability for future adjustments or modifications.
Choosing the Right System
The selection between bonded and unbonded hardscape systems depends on several factors, including the expected load, maintenance approach, climate conditions, permeability requirements, and budget. Given the choice, most would prefer the enhanced durability and longevity of a bonded system, but cost constraints often dictate the use of unbonded systems, which provide a practical and adaptable alternative.
Both installation methods can be designed to support drainage and longevity when paired with appropriate materials. For guidance on selecting the best system for your project, ROMEX Hardscapes provides expert consultation and product solutions tailored to different applications.
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