Measure the gap first, because the gap picks the solution. A difference of 1/4 inch or less is usually handled with a low-profile reducer or edge cap. Between 1/4 and 1/2 inch you need a true sloped reducer. Past 1/2 inch, a strip alone stops being the answer. You need to build up the low side, plane or feather the high side, or add a ramp.
This guide walks through each range. It also covers how to measure correctly, what the ADA says, and the mistakes that cause trips and cracked edges.
TL;DR
- Measure the finished height of both floors, including underlayment, adhesive and any leveler, not the loose plank or tile thickness.
- Same height: T-molding. Small step: reducer or edge cap. Large step: fix the subfloor build-up or use a ramp profile.
- On accessible routes in commercial and public spaces, the ADA treats a change in level over 1/2 inch as a ramp.
- A flush look is not always the safest look. A visible strip warns your feet that the surface is changing.
- Plan the transition before you order flooring. Choosing a different thickness or installation method often removes the problem.
Table of Contents
- Why two floors end up at different heights
- How to measure the height difference
- Choosing a transition by height difference
- What the ADA says about changes in level
- Is a flush transition always better?
- Fix the difference before it exists
- Common mistakes at the doorway
- Our perspective
- Get the right materials for the gap
- FAQ
- Sources
Why two floors end up at different heights
Height differences are normal, and they are rarely a mistake by anyone. Retrofitting new flooring over an old surface, mixing materials of different thickness, uneven subfloors and code-driven build-ups are common reasons floors meet at different levels.
In Michigan homes, we see the same few situations again and again:
- Hardwood next to tile. Tile sits on a bed or backer board, so the finished surface can land above or below the plank next to it.
- Hardwood next to carpet. Carpet and pad compress, so the step shifts depending on what goes in.
- Thin vinyl or laminate next to existing hardwood. Click-lock planks are often thinner than nail-down hardwood, so the new room sits lower.
- Old room, new room. An addition or a remodeled basement rarely matches the original floor height.
All of these are predictable if you measure before you buy.
How to measure the height difference
Most bad transitions start with a bad measurement. Here is the process we recommend to homeowners and installers alike.
- Decide on the finished floors first. Know what will actually be installed on each side, including underlayment, vapor barrier, adhesive, mortar and any self-leveler.
- Add up each side’s build-up. Subfloor surface to top of the finished floor, measured at the doorway.
- Measure at several points across the opening. Doorways are often not level, so the step at the left jamb can differ from the right. Take the largest and smallest reading.
- Lay a straightedge across. Rest a level or straightedge on the higher floor and measure the drop to the lower one. This is the number your strip has to cover.
- Note which side is higher. A reducer slopes down toward the lower floor, so direction matters when you order.
If the floor is uneven overall, not just at the doorway, read our guide to flooring that handles uneven floors before you pick a product. A transition strip cannot hide a subfloor that is out of flat.
Choosing a transition by height difference
| Height difference | Typical solution | Notes |
|---|---|---|
| None (same height) | T-molding | Sits over the joint. On floating floors it can also cover the expansion gap. |
| Up to about 1/4 inch | Low-profile reducer or edge cap | Protects the exposed edge and softens the step. |
| About 1/4 to 1/2 inch | Sloped reducer sized to the height | Choose a profile made for that height, not a generic strip. |
| Over 1/2 inch | Build up the low side, feather or plane the high side, or use a ramp | A strip alone leaves a steep, hard-to-trip-over-or-not edge. Fix the build-up. |
The thresholds above line up with the accessibility limits discussed in the next section, which is a useful benchmark even in a private home.
Same height: T-molding
When both floors finish at the same level, a T-shaped strip bridges the seam. The stem sits in the gap and the cap covers both edges. It is the cleanest option, but it only works when the levels truly match. Using a T-molding across a step forces one edge to sit under the cap and the other to stand proud, which chips the higher floor over time.
Small step: reducers and edge caps
A reducer ramps from the thicker floor down to the thinner one. An edge cap (sometimes called an end cap) finishes the exposed edge of a floor where it meets a lower surface, such as a sliding door track or a sunken room. For a step of 1/8 inch, a low-profile reducer is usually enough. Homeowners often ask whether they can simply leave a 1/8 inch lip. You can, but it is a classic toe catcher, and the bare edge of a plank or tile is the first thing to chip.
Moderate step: sized reducers
Between 1/4 and 1/2 inch, buy a reducer made for the actual height rather than stretching a small one. The slope is gradual enough to walk across without noticing, and the strip is anchored on the higher side where the thickness is enough to hold a fastener or adhesive. For a deeper look at how these strips behave in a doorway, see what a threshold strip actually does.
Large step: stop covering, start correcting
Once the difference passes about 1/2 inch, a strip becomes a steep wedge. At that point there are three realistic options:
- Raise the low side. Add plywood underlayment, a patching compound or a self-leveling underlayment, depending on the floor going over it.
- Lower the high side. On some jobs the old floor, underlayment or sleepers can come out before the new floor goes in.
- Build a ramp. For a difference of an inch or more, such as a sunken living room or a garage-to-house entry, a real ramp or a step with a nosing is safer than a long strip.
A step of 2 inches or more is not a transition problem. It is a framing or design decision, and you should involve your builder.
What the ADA says about changes in level
Your home is not covered by the Americans with Disabilities Act. But the ADA numbers are the best published yardstick for what is safe underfoot, and they apply on accessible routes in businesses, offices, and other public spaces.
The 2010 ADA Standards set three tiers for changes in level on floor surfaces:
- Up to 1/4 inch may be vertical.
- Between 1/4 inch and 1/2 inch must be beveled with a slope no steeper than 1:2.
- Anything over 1/2 inch must be treated as a ramp or curb ramp.
The Access Board’s guide to the standards restates the same three tiers in plain language. If you are a contractor or retailer doing a storefront, clinic or office, confirm the requirements with the local building official and your project’s accessibility consultant. Local codes and project type can add to these limits.
For a home with a family member who uses a walker, cane or wheelchair, treat 1/4 inch as your ceiling for a square edge and keep any bevel as low and gradual as you can. Our guide to non-slip flooring for elderly homeowners covers surface choices for the same households.
Is a flush transition always better?
Not necessarily. Many homeowners want a floor that runs unbroken from room to room. That is a good goal when the levels match and the materials can share an expansion joint. But when the floors differ in height or material, professionals often prefer a visible strip. The Spruce’s guide to transition strips notes that these strips manage changes in floor height and material while connecting rooms safely.
A visible strip gives your foot and eye a clear cue that something is changing, which matters in a busy doorway or a dim hallway. A hidden or ultra-flush solution looks sleek, but it asks the floors to behave perfectly for years.
Fix the difference before it exists
The cheapest transition is the one you never need. Before ordering, check these choices:
- Pick thickness with the neighbor in mind. If a new vinyl or laminate floor will meet existing hardwood, compare the finished heights first. Our laminate and luxury vinyl plank lines come in different thicknesses, and we can help you match the build-up to the room next door.
- Choose the installation method on purpose. Nail-down, glue-down and floating systems add different amounts of height. Read floating vs nail-down installation to see how that changes the finished level.
- Mind the expansion gap. Floating floors and hardwood both need room to move. The strip must cover that gap without pinning the floor down. Our expansion gap checklist for installers lays out the numbers.
- Match color and species at the doorway. If you are adding to an existing floor, see how to match existing hardwood flooring, since a seam that is close in color but off in height looks worse than either alone.
If you are choosing between product types, our comparison of engineered vs. solid hardwood flooring explains how thickness and construction affect where your floor ends up.
Common mistakes at the doorway
- Measuring before underlayment. The difference changes once the pad, membrane or leveler goes down.
- Using a T-molding across a step. It looks right on day one and chips by year two.
- Forcing a tiny reducer to cover a large drop. The slope ends up steep and the strip can crack or lift.
- Fastening through a floating floor. Nailing or screwing a floating plank locks it in place and invites buckling. Anchor the strip to the subfloor or use a track that leaves the planks free.
- Ignoring the doorway’s out-of-level. A single strip length rarely fits a doorway that drops 1/8 inch from one jamb to the other. Shim, scribe or level.
- Choosing the strip last. Order the transition with the floor so the species, color and height all line up.
Our perspective
We have supplied flooring to Michigan contractors, builders and homeowners for more than 40 years, and the doorway is where we get the most calls we could have prevented. The usual story: a floor was ordered by its look, installed, and only then did anyone notice that it sat 3/8 inch above or below the room next door.
Our advice is simple. Bring us the height of the existing floor, the room it meets and the product you are considering. Our staff have years of installation and builder experience, so we can tell you which thickness, underlayment and strip will land on the same plane, or whether the honest answer is a short ramp. We also recommend a visible, well-fitted strip over a flush hack that will chip. A good transition is boring: you never think about it.
We do not install floors ourselves, but we can refer you to installers we trust and talk through the job with them before the first plank goes down.
— Mike Solomich
Get the right materials for the gap
If you are planning a floor that meets another surface, talk to us before you order. We carry solid, engineered and unfinished hardwood, luxury vinyl plank, SPC, laminate, stains, finishes and abrasives, with contractor pricing for all buyers. Browse hardwood flooring options or visit our home page to get a quote by phone or online, then pick up at the showroom or have it delivered statewide.
FAQ
What is the maximum floor transition height allowed?
In private homes, no federal rule sets one. On accessible routes covered by the ADA, a change in level over 1/2 inch must be treated as a ramp, and changes between 1/4 and 1/2 inch must be beveled no steeper than 1:2. Check your local building code for anything beyond that.
What is the transition piece between floors called?
The name depends on the job. A T-molding joins floors of equal height, a reducer slopes down to a lower floor, and an edge cap finishes an exposed edge. A threshold is the broader term for the strip under a door.
What can I use instead of a transition strip?
If the floors are at the same height and both can be fastened, you can butt them with a small gap filled with flexible sealant or run the same flooring through the opening. When heights differ, correcting the build-up with underlayment or leveler is the real alternative. Floating floors still need an expansion allowance, so do not butt them tight.
Can I fix a 1/8 inch difference without a ramp?
Usually, yes. A low-profile reducer or edge cap is made for that size of step. If the difference is a floor-wide problem rather than just at the doorway, address the subfloor first.
Sources
- Chapter 3: Building Blocks, 2010 ADA Standards (U.S. Access Board)
- Guide to the ADA Standards, Chapters 1 to 5 (U.S. Access Board)
- Guide to Floor Transition Strips (The Spruce)
- Joining Two Different Level Floors (Flooring Clarity)