Threshold / Transition Strip

A strip or bar fitted at a doorway to create a neat transition between two different flooring surfaces or levels.

A threshold (also called a transition strip, door bar, or cover strip) is the strip of material fitted across a doorway where two floor surfaces meet. It provides a clean, safe transition — whether the floors are the same material at the same level, different materials, or at slightly different heights.

Why thresholds matter

Without a threshold strip, the edges of flooring at a doorway are exposed and vulnerable to damage, lifting, and tripping hazards. Thresholds also cover the expansion gaps that floating floors (like LVT and engineered wood) need around their perimeter to allow for natural movement.

Types of threshold strip

  • Flat / cover strip — for two floors at the same height. Sits flat over the joint.
  • Ramp / reducer — for a transition from a higher floor to a lower one. One edge is raised, the other tapers down.
  • T-bar — for two floors at the same height that both need an expansion gap. The T-shaped profile sits between and slightly above both surfaces.
  • Z-bar / stair nosing — for transitions at the edge of a step or a significant height difference.

Materials

Threshold strips come in aluminium (affordable, durable, wide colour range), solid wood or oak (matches wood flooring for a seamless look), brass (premium look, often used in period properties), and PVC (budget option, flexible). The material should complement your flooring choice — a brushed aluminium strip on a rustic oak floor will look out of place, just as a dark oak strip between two light-coloured floors would jar.

Installation tips

Discuss threshold placement with your contractor before flooring installation begins. Key decisions include:

  • Where exactly — centred under the closed door is standard
  • How they are fixed — screw-down (visible fixings) or adhesive clip systems (hidden fixings for a cleaner look)
  • Colour matching — order thresholds at the same time as flooring so they are from the same range

Thresholds are a small detail, but choosing them carelessly can undermine the look of an otherwise well-finished renovation. Include them in your scope of work so they are not an afterthought.