Handrails must be at a height that the average person can grab readily as they go up or down steps. Some jurisdictions require railings to be 31 inches to 36 inches above the nosings of the steps. In other jurisdictions, they have to be 34 inches to 38 inches above nosings. Check your area requirements.
In many areas, the guardrails must be 42 inches high around landings, decks and balconies. In other areas, they can be only 36 inches high if the deck is less than six feet off the ground.
It's important to note that the required height of handrails going up the stairs may not be the same as the required height of the guardrails at the landing around the top of the stairs.
The cause of incorrect handrail or guardrail height is an original construction issue. People seem to get taller with each successive generation, and, in many old buildings, handrails and guardrails are considerably lower than what we would build today.
From a safety standpoint, we recommend that the railings be replaced. Temporary handrails and guards or extenders are possible solutions to maintain architectural appeal over the long term and protect a busy youngster in the short term.