Study finds using RVK 101 telescopic connectors instead of RSAs delivers 33% cost savings

A recent report evaluates the costs of materials and labour to support precast concrete landings off core walls. Comparing costs for RVK 101 connectors and rolled steel angles (RSAs) show that telescopic connectors yield one third (33%) reduction in costs with only one fifth (20%) of labour.

Furthermore, robustness anchorage is inherent to the layout of telescopic connectors, without any of the additional measures or expenditure typically required by RSAs support method.

Invisible Connections has seen a significant and growing take-up of TSS and RVK telescopic connectors; a three-fold increase in three years suggests contractors and precasters are recognising the value of this alternative connection method to the construction process. For them, value isn’t just delivering lower costs, but also generating the added value of reduced waste, cranage and noise as well as increased safety, robustness, speed and efficiency. All of which contribute to bottom line savings.

Any claim for savings between methods is open to challenge owing to site variables. However, the extent of the costs saved suggests adjustments to any of the cost elements would have to be significant to produce a result which does not favour telescopic connectors.

Meeting the needs for robustness

It’s important to point out the study does not take into account the additional measures contractors must often take to ensure design requirements for robustness are met. Where RSAs are used, this can include using pull-out bars or threaded couplers tied into structural toppings. Alternatively, when telescopic connectors are used, assuming connections into three sides of the landing are possible, design requirements for robustness can normally be satisfied without any additional procedures. Arguably then, robustness anchorage is ‘free.’

Similarly, in circumstances where three-sided connection layouts aren’t possible, ‘pinned’ versions of telescopic connectors offer a far more cost efficient robustness solution than alternative methods, even when their small cost premium is taken into account.

This theoretical cost exercise was originally reviewed by both contractors and precasters. Challenges were invited, and continue to be encouraged, in order to maintain confidence in the reasonableness of the calculations as well as their relevance and accuracy over time.

To view the report, download it here.


Telescopic connectors provide us numerous advantages for precast stair installation. Apart from improved time and efficiency, the health and safety gains over traditional support methods are a key driver to satisfy our own needs, as well as those of our clients.

Shane Dunleavy, Project Manager, Morrisroe