Transitions, Trim & Finishing
Transition strips, T-moldings, reducers, stair nosing, baseboards, quarter round, and floor flanges.
- Identify transition strip types and their correct applications
- Describe baseboard, quarter round, and stair nosing installation
- Explain floor flange and penetration finishing methods
- Describe floor finishing, polishing, and buffing procedures
- State the purpose of each transition type in a flooring system
Lesson 1
Transition Types - T-Moldings, Reducers & Thresholds
Why Transitions Matter
Transition strips are required wherever two different flooring materials meet, where flooring changes height, or at doorways between rooms. They serve both functional and aesthetic purposes - protecting exposed edges, bridging height differences, and creating a clean visual break.
T-Molding
Use: Two floors at the same height
Shape: T-profile bridges the gap
Example: Laminate to laminate at doorway
Reducer
Use: Higher floor to lower floor
Shape: Ramp from high to low
Example: Hardwood to vinyl at doorway
Common Transition Types
| Transition | Purpose | Typical Location |
|---|---|---|
| T-Molding | Same-height transition | Doorways between rooms |
| Reducer | Height change ramp | Where thick meets thin flooring |
| Threshold | Flooring to non-flooring | Exterior doors, bathroom entries |
| End cap | Exposed edge protection | Sliding doors, fireplace hearths |
| Stair nosing | Stair tread edge | Top step and each tread |
Installation Methods
Transitions install using either a track system (metal or plastic track screwed to subfloor, molding snaps in) or direct adhesive (construction adhesive applied to the subfloor). The track system allows for flooring expansion beneath the transition.
Expansion Gap Under Transitions
Floating floors must maintain an expansion gap under transition strips. The transition covers the gap but must not pin the flooring. Use the track system to bridge the gap without restricting movement.
T-moldings bridge same-height floors. Reducers ramp between different heights. Thresholds finish at exterior doors. Always maintain expansion gaps under transitions for floating floors.