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What are carpet shims used for and which one do I need?

Install carpet shims under a carpet across a doorway and create a gentle, upwards gradient to create a smooth transition. In so doing, you can avoid creating unwanted mini-steps in your home. Carpet shims solve level differences from 15mm to 35mm when joining a carpet to hard floorcoverings such as porcelain tiles, marble floors, stone and so on.

How to tackle the issue of a raised bathroom floor due to underfloor heating

A common scenario is where a difference in height between the level of a carpeted landing and a newly tiled bathroom floor results following retro-installed underfloor heating. Whether a wet or electric system, an underfloor system typically raises a floor level. Components such as electric mesh, water pipes, screed and insulation all contribute to the issue.

Raised tiled bathroom floor copared to landing carpet
Carpet Shims create a gentle slope under a carpet as it approaches a doorway – the smart way to avoid a step

What are carpet shims?

The popular Easyshims brand of carpet shims is made of mdf. The shims are available in a choice of four slope gradients: 6mm, 9mm, 12mm, 15mm. They are ideal for installing under carpet next to hardwood, ceramic tile, stone and the like when there is a step up in the doorway from the carpet. Easily cut to fit around door frames, the Easyshims lift the carpet level up to the hard flooring and are ideal for combining with a carpet door bar to prevent the carpet from undue wear and to create an elegant join.

Wedge-shaped Easyshim to create slope under a carpet, close-up, 15mm
The Easyshims come in 6mm, 9mm 12mm & 15mm thicknesses and packs of 4

Likewise, side shims can be made from a single Easyshim, which means you can feather in the gradient as you approach the doorway from the side. Please see the manufacturer’s video.

Are they easy to fit?

Carpet Shims are simple to do-it-yourself install. However, first make sure you do your calculations correctly and watch the manufacturer’s fitting videos. (Please note Easyshims are available in 4 per pack, not the 10 trade pack mentioned in the videos). Combined with a variety of door bars, Easyshims solve no end of flooring level issues.

Fitting Easyshims with a Z Bar door threshold

When joining a carpet to another floorcovering you can use a variety of door thresholds and plates, including the Premier Double Z9 (joins two carpets) or the Premier Z9 (joins carpet to another type of floorcovering). These come with 3mm MDF spacers which slip under the bar to lift it and create a suitable angle for the carpet to fit onto the base spikes/pins. When fitted, the door bars are “napped down” around 3mm for a secure fit. Note, only the carpet fits into the door bar, not the underlay which stops short and is therefore not part of the following calculations.

Example 1 : a tiled floor is 16mm higher than the landing floorboards on which carpet is to be fitted. Which height of Easyshim is needed?

  • The Premier Z9 door transition strip is a quality way to join the two, where the bar neatly sits over the edge of the tiles and caters for compressed carpet up to 9mm thick. However, IT MUST LIE flat. The Z9 is set at 10mm i.e. the visible bar that sits over the top of the tiles and carpet caters for 10mm thick tiles and carpet.


10mm Premier Z9 + 3mm spacer – 3mm nap + 6mm Easyshim = 16mm height difference.

Example 2: a tiled floor is 28mm higher than a landing’s bare floorboards on which a carpet is to be fitted. Which height of Easyshim should you use?

  • All the Premier Z bars are supplied with 3mm spacers which you should slip under the door bar to lift them and angle the pins correctly. If extra lift is required, you can use 2 spacers stacked on top i.e. making 6mm.


10mm Premier Z9 + 2 x 3mm spacer – 3mm nap + 15mm Easyshim = 28mm

Example 3: a marble floor is 34mm higher than a landing’s bare floor boards on which carpet is to be fitted. How can you bridge such a large difference in floor levels?

  • The Compression Ramp works well in this situation, avoiding any trip hazards.
  • The Ramp sits on the surface of the carpet and tiles and therefore you will need gripper under the carpet across a doorway to hold it in place.


Premier Compression Ramp 5mm + 7mm gripper + 10mm carpet – 3mm nap + 15mm Easyshim = 34mm

Example 4: a wooden floor is 40mm higher than the concrete hall floor on which an extra thick carpet is fitted. Which height of Easyshim should you use?

  • The carpet is a thick 15mm one and compresses down to around 12mm and therefore the Premier Z13 should be the ideal Z bar. All the Premier Z Bars are supplied with 3mm spacers which you can slip under the door bar to raise it.


Premier Square Lip 15mm + 15mm carpet + 6mm gripper + 6mm Easyshim = 41mm

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