The standard marble threshold is 3/4 inch thick, and that is the right choice for most doorways. What really matters is where the top of the saddle ends up compared with the finished floor on each side and the bottom of the door. Pick the thickness and bevel that keep the top close to both floors and leave the door room to swing. Where accessibility matters, keep the step at 1/2 inch or less.
Why is 3/4 inch the standard thickness?
Our standard stock saddles are 3/4 inch thick, in lengths of 24, 30 and 36 inches and widths of 3 to 6 inches. It is a common thickness in the trade: solid enough for daily foot traffic, and in many bathrooms close to the height of the finished tile once the thinset is under it.
In practice, a 3/4 inch saddle set on the same subfloor as the tile often finishes near the tile surface. That is why it works for the everyday bathroom door. Our best sellers, such as the 36 x 4 x 3/4 inch saddle, are all this thickness.
What decides the right thickness for your doorway?
Thickness is never chosen on its own. Three things set it:
- The finished floor height on each side. Tile plus its setting bed, hardwood, vinyl plank and carpet all finish at different heights. The top of the saddle should land at, or a little above, the higher floor.
- What the saddle sits on. The stone goes down in thinset or mortar, just like tile. A thick mortar bed on one side, or a subfloor that dips at the doorway, changes the math.
- Door clearance. The door has to swing over the saddle, and over any rug or mat on the far side. If the bottom of the door is already tight, a taller saddle will make it bind.
When the door rubs, installers usually trim the bottom of the door rather than look for thinner stone. Planning this before the door is hung saves a trip back.
How do you measure the floor heights?
Do this with both floors finished, or with samples of the finished flooring laid in place.
- Lay a straightedge or level across the doorway, resting on the higher floor.
- Measure from the bottom of the straightedge down to the lower floor. That is your height difference.
- Measure from the subfloor in the doorway up to the top of each finished floor. This tells you how much the saddle and its setting bed need to fill.
- With the door closed, measure the gap between the bottom of the door and the subfloor in the opening.
- Write the numbers down with a quick sketch showing which side is which.
Our measuring guide covers length and width too, so you can get every dimension in one pass.
Which thickness and profile fits your situation?
This table sums up what we recommend most often. Use it as a starting point, then check it against your own measurements.
| Situation | Recommended thickness | Recommended profile |
|---|---|---|
| Tile on one side, floor at about the same height on the other | 3/4 inch stock | Standard bevel (1/4 inch chamfer on one long edge) |
| Tiled bathroom next to a lower wood, vinyl or carpet floor | 3/4 inch stock | Single Hollywood, slope facing the lower floor |
| Saddle sits above the floor on each side of the door | 3/4 inch stock | Double Hollywood |
| Thick mortar bed or a deep gap that 3/4 inch cannot fill | 1-1/4 inch custom | Usually a Hollywood slope toward the lower floor |
| Accessible or commercial doorway | Whatever keeps the step at 1/2 inch or less | Hollywood slope; confirm the bevel meets the 1:2 rule |
| Door bottom too tight over a 3/4 inch saddle | 3/4 inch stock | Trim the door; adjust the setting bed if needed |
When do you need a thicker 1-1/4 inch threshold?
A 1-1/4 inch saddle is a custom piece. It makes sense when the opening needs more height than 3/4 inch stone can give without building up a thick bed of mortar under it.
Common cases include a bathroom floor set on a thick mortar bed, an old house where the subfloor at the doorway sits lower than the rooms on each side, and exterior doors where the stone has to meet a raised sill. In these jobs a thicker stone gives a solid, full-depth support instead of a thin piece perched on a tall pile of thinset.
We cut thicker and longer pieces to order. See custom marble thresholds to request one, and the shower threshold page if the piece sits at a shower entry.
When is a Hollywood slope better than a thicker piece?
If the problem is a height difference between two floors, a slope usually solves it better than extra thickness. A thicker saddle only raises the step. A sloped edge turns the step into a ramp you can walk or roll over.
- Use a single Hollywood bevel when one floor is lower. The slope faces the lower floor and the square edge butts against the higher one.
- Use a double Hollywood bevel when the saddle sits above the floor on each side, such as a bathroom lip meant to hold water.
- Use a standard bevel when the floors already meet the stone at about the same height. Its small 1/4 inch chamfer is on one long edge only and softens the corner; it is not meant to make up a height difference.
How does thickness relate to the ADA 1/2 inch limit?
The 2010 ADA Standards limit thresholds at doorways to 1/2 inch high. A change in level up to 1/4 inch can be left square. Between 1/4 and 1/2 inch it must be beveled no steeper than 1:2, and anything over 1/2 inch has to be ramped.
So the thickness of the stone is not the number that counts. What counts is how far the top of the saddle sits above the floor next to it. A 3/4 inch saddle set down in the same bed as the tile can easily meet that limit. One perched on top of a finished floor cannot, unless it qualifies for the exception for existing or altered thresholds, which allows up to 3/4 inch with a bevel on each side no steeper than 1:2.
Private homes are generally not covered by the ADA, but the same numbers are good practice for anyone who uses a walker or wheelchair. Our ADA threshold guide has the full height table. Always confirm with your local code official.
Know your heights and need help choosing? Send us the measurements through the contact page and we will suggest a size and profile.
Frequently asked questions
What is the standard thickness of a marble threshold?
3/4 inch. Our standard stock saddles are 3/4 inch thick, in lengths of 24, 30 and 36 inches and widths of 3, 4, 5 and 6 inches. Thicker pieces are cut to order.
Should the threshold be higher than the tile?
At a bathroom door, many installers set it level with the tile or a little above, so it forms a small lip that helps hold water in. On the other side, a Hollywood slope brings it down to the lower floor. Keep accessibility limits in mind if the step gets taller.
Can I use a 1/2 inch thick threshold instead?
Our standard stock is 3/4 inch. If a 3/4 inch saddle sits too high, the usual fix is to set it lower in the bed, use a Hollywood slope, or trim the door, rather than switching to thinner stone.
Does a thicker threshold need a different installation?
The method is the same: a full bed of thinset or mortar with no hollow spots. Thicker stone is heavier, so dry fit it and check the door swing first. Our installation guide walks through it.
What size should I order?
Match the length to the door opening and the width to the wall depth. Read what a marble threshold is for an overview of sizes, stones and finishes.