The business employs around five gangs delivering a revenue that is believed to have reached up to £8m.
A top-five sheet piling specialist operating in the London basement market, Keltbray was impacted by stalled projects due to Brexit uncertainty.
Up to 20 staff are thought to be affected by the decision although Keltbray aims to redeploy workers where it can to retain expertise within the business.
Keltbray will work out existing contracts with a view to closing the operation in April.
A Keltbray spokesperson said: “Our sheet piling business unit was initially established to provide support to a complete in-house, combined self-delivery specialist service as part of our central London market offering.
“Over the last 18 months or so, the obvious reduction in workload in that core market has forced the business unit to look elsewhere and much wider afield for works opportunities.
“The combined group service value proposition to clients rarely exists in these works opportunities and the scale of the projects are proportionately smaller.
“Furthermore, associated margins levels are particularly aggressive and not commensurate with the scale of investment required and risk borne by such specialist services providers.”
She added: “We are working hard to reposition elsewhere in the group the people affected, and believe the actual number of redundancies to be single figures at worst.
“With the repositioning of personnel within the business we will maintain within the piling business the ability to carry out sheet piling on combined concrete and sheet piling projects.”