Flooring Transitions Between Rooms: The Doorway Checklist From the Manuals

The installation manuals for the floating floors we carry all warn about the same doorway mistake: nailing or screwing a transition strip through the floor itself. Pin the floor at the doorway and it can’t expand and contract, which is the job the gap under the strip was there to allow.

Flooring transitions between rooms are the pieces that cover that expansion gap where one floor stops, and that bridge any height difference between two floors. Choose the piece by height, leave the gap your floor’s manual asks for, and fasten the strip to the subfloor or the wall, never to the planks.

The five transition pieces and when each one fits

• T-molding: joins two floors of about the same height, or splits one long floating floor into sections at a doorway.
• Reducer: ramps a thicker floor down to a thinner one, such as 5/8″ engineered hardwood meeting thin vinyl or an existing low floor.
• Threshold or end cap: finishes a floor that stops against something vertical, like a sliding-door track or a raised hearth.
• Stair nose: finishes the front edge of a step or a landing.
• Quarter round or shoe molding: covers the expansion gap along walls and cabinets, attached to the wall.

The lines in our showroom don’t all offer the same pieces. Our Chesapeake engineered collections list quarter round, reducer, stairnose, threshold and T-molding.

Fusion Design XL in our laminate flooring lines lists quarter round, flush stairnose, overlap stairnose and a “5 in 1” molding; All American Premium lists quarter round, Incizo 5N1, an Incizo stair base and stairnose. Veranda’s engineered collections note that coordinating molding is available.

The doorway checklist, item by item

Work through these eight checks for each doorway or opening. Each one comes from an installation document for a floor we stock; where the brands disagree, we show both numbers.

1. Look up the expansion gap your floor needs

The strip has to cover the gap, so start with its width. PermShield asks for 1/4″ around rigid-core vinyl in areas up to 2,500 sq ft and 1/2″ in larger ones. Chesapeake laminate asks for 3/8″. Chesapeake engineered asks for a gap equal to the floor’s thickness, and Denali for at least 1/2″.

2. Check whether the doorway requires a T-molding

Some floors may run straight through a doorway; others may not. Chesapeake’s laminate guidelines (June 2025) require a T-mold in doorways narrower than 32″, where the installation changes direction, and when the floor runs more than 40 lineal feet. Another passage in the same document sets field expansion at 50 feet, so plan around 40.

Chesapeake’s Points East engineered floor is stricter when floated: every doorway less than 6 feet wide gets a T-molding, and so does any run over 40 feet.

The photo from our vinyl gallery shows one floor running through a cased opening with no strip. That works only when the manual for that floor has no doorway rule that applies, and the run stays inside its length limit.

3. Measure both finished heights

Compare the floors as they will sit, pads included. Our Belocore SPC planks are listed at 4.4 mm; Fusion Design XL laminate is 12 mm with its 2 mm pad; Points East engineered is 1/2″ and Cromwell is 5/8″. Close heights take a T-molding; a clear step down takes a reducer.

There’s another option for rigid-core vinyl. PermShield’s instructions allow plywood, OSB or another rigid material under its planks to bring them up to an existing floor’s height, without affecting performance or warranty. Don’t add a second soft pad to gain height; we explain the pad limits in our guide to underlayment for vinyl plank flooring.

4. Choose the profile from the floor’s own molding list

Buy the strip made for the floor, so the color, height and locking edge match.

The lists in the first section come straight from our product pages. For a combined profile such as “5 in 1” or Incizo 5N1, ask us at the TRD Floor Supplies showroom which shapes it can be cut into before you plan a doorway around it.

5. Undercut the door casing, not the floor

Door casings and jambs get trimmed so the floor slides underneath with room to move. Chesapeake’s laminate guidelines call for 1/16″ of clearance under the cut casing, and Denali asks for casings cut 1/16″ higher than the flooring thickness. PermShield asks for every door jamb to be undercut.

6. Fasten the strip to the subfloor, never through a floating floor

Moldings and transitions attach to the wall or the subfloor, never to floating planks. PermShield says not to fasten moldings or transition strips to the planks. Chesapeake says never to affix moldings to the floor.

Hallmark’s instructions for floating installations fasten lip-over moldings to the subfloor only; on glued floors, Hallmark sets transition moldings with urethane glue or a high-quality adhesive.

7. Blend boards and order trim from the same run

Wood moldings and the boards beside them should look like one floor. Denali tells installers to pick the boards that best blend with the color of stair treads, nosings, reducers and T-moldings, and Hallmark says to set those boards aside at the start.

Denali also allows up to 5 degrees of gloss variance and 5% color difference between production runs. Order your transitions together with the floor, and look at them next to the boards before anything is nailed.

8. Seal wet doorways with silicone

At a bathroom door, or anywhere the floor meets a tub or shower base, Chesapeake’s laminate guidelines fill the expansion space with 100% silicone caulk, not acrylic, and then cover it with molding.

The same document leaves a gap around the toilet flange and fills it with silicone. Our article on laminate flooring in a kitchen covers the other wet-area rules for that floor.

Doorway checklist to print

Take one copy per doorway to the showroom or the job site:

1. ☐ Floors on each side: product name and line.
2. ☐ Expansion gap each manual requires at this doorway: ____ and ____.
3. ☐ Doorway width: ____. Does either manual require a T-molding here (width, change of direction, run length)?
4. ☐ Finished height of each floor, pads included: ____ and ____. T-molding, reducer, threshold or build-up?
5. ☐ Profile chosen from the floor’s own molding list, same color and production run.
6. ☐ Door casings and jambs undercut with clearance.
7. ☐ Strip fastened to the subfloor or glued per the manual, not through floating planks.
8. ☐ Boards beside the molding blended for color.
9. ☐ Wet doorway: 100% silicone where the manual asks for it.

What adds to the cost of transitions

No price list here, since those numbers shift. What changes a transition quote is the job itself:

• How many doorways, openings, stairs and landings the floor crosses.
• The profile: a T-molding, a reducer, a threshold or a stair nose, and whether it’s a matching factory molding or a combined profile.
• The floor line it has to match, and whether that molding is in stock or ordered with the floor.
• Prep work: undercutting casings, building up a thinner floor, or adhesive and silicone where the manual calls for them.

Bring the checklist with your measurements to our flooring store in North Charleston or our Richmond showroom, and we’ll match each doorway to the right piece for both floors. You can also schedule a showroom visit before you buy.

Manuals quoted above: PermShield rigid core installation instructions (revised September 1, 2023); Chesapeake installation guidelines for laminate and for engineered hardwood (June 1, 2025); Chesapeake Points East installation, maintenance and warranty guide; Denali Hardwood Floors installation guidelines (revised January 19, 2026); Hallmark Floors engineered hardwood installation instructions; molding options on TRD Floor Supplies product pages.