Fitting Internal Door Thresholds when One Floor is Higher than the Other

A common question we are asked by customers is:  which internal door thresholds they should use if their tiled bathroom floor is higher than their carpeted landing and they want to join the two in a doorway. The problem seems to be particularly prevalent in bathrooms where installation of underfloor heating can raise the tiled floor.

The diagram below shows the profile of a typical Single Naplock or Z Bar.

Premier Door Bar (Z) internal door thresholds

Profile of a Premier Door Bar (Z) internal door threshold

Here are a few tips and a choice of door bars which we would recommend:

The Single Naplock Internal Door Thresholds Solution

The Single Naplock (i.e. teeth on one side of the base) grips the carpet and holds it in place, whilst the visible bar covers the two edges of (1) the carpet and (2) the tile.  It looks smart, is very robust and is very secure.  The Single Naplock door threshold design works well if your carpet and tiled floor are the same height. If the tiled floor is higher by a few millimetres then you can chock up or raise the door bar by inserting a slender piece of wood underneath it. If the difference is more, then we suggest you use a proprietary product such Easyshim, which acts as a ramp underneath the carpet as it rises up to the door bar and the height of the tiled floor.

You can do likewise with any hard floor, including wood or laminate, when you are joining to a carpet.

There are two Single Naplocks internal door thresholds to choose from on the Carpetrunners shopping website.  The Premier Door Bars (Z) are made of brass with an aluminium base and then plated in a choice of 9 different finishes. Or the Feline 1, which has a pristine appearance and is made in solid brass and offered in 5 different metal finishes.

Premier trim z internal door threshold

Joining a hard floor to carpet using a smart internal door threshold

Using a Cover Door Plate

Cover Door Plate is another type of internal door threshold and joins two flooring surfaces together. But, unlike a Single Naplock, it sits over the gap between the two. The entire Cover Door Plate is above the surface of the flooring.  You would, therefore, securely fit your carpet in the normal way, using gripper or the like.  Should the two floors that you are joining be slightly different heights, then the cover door plate will simply ramp up or down from one to the other.


The Posh cover door plate joins flooring of differing heights

There are a few different designs which are particularly smart: the Premier Cover Door Plate is made in solid brass and available in nine metal finishes and is a contemporary design which reveals the matching screws down the centre.

The Posh and the Joints door thresholds are similarly designed, only the Posh is made from solid brass and the Joints are made in a thick gauge aluminium in a number of different finishes.  Both the Posh and the Joints are attached to your floor with central screws, which are then hidden beneath a matching metal strip. The Posh comes in an attractive patterned effect or plain.

Posh antique brass door threshold

The Posh Cover Door Plate creates a smart join