Yes, a 12mm underlay is generally considered too thick for stairs. Most flooring experts and fitters recommend an underlay thickness of 8mm to 10mm for staircases.
Popular manufacturers make underlay of around 11mm-12mm and this is ideal. Although for more difficult areas like stairs, a 9mm underlay would be far easier to fit, rather than something as much as 12mm.
For stairs, the optimal thickness is always 9–10 mm, as anything thicker becomes difficult to fit safely around stair nosings. While thicker foams feel softer, they must still be dense enough to cope with the heavy, repetitive use that stairs receive.
So generally speaking 7mm is about as thin as you want to go unless you have a specialist need for something thinner, but 8-12mm is the band most manufacturers produce carpet underlay with and its perfect for any room and any carpet. So go thicker if you can afford it!
The thickness of the underlay plays a role here: an 8mm pack provides firm everyday support, while 10mm and 12mm options offer greater cushioning for households looking to make stairs feel softer underfoot.
For living rooms, dining rooms and general family spaces, 10mm laminate is a reliable middle option. It feels more solid than 8mm while staying practical for most homes. For hallways, busy areas and larger rooms, 12mm laminate can be a good choice if you want a weightier feel and the extra height is not an issue.
Overly grand staircases and ornate rail details are both considered outdated by designers. LED strip lights and floating steps may feel modern and futuristic, but are actually out of style. Carpeted stairs aren't always seen as stylish, but they can be elevated and modernized.
The best thickness depends on your room and subfloor. For high-traffic areas like living rooms or hallways, 10-12mm is ideal. For lower-traffic spaces with a level subfloor, like bedrooms, 7-8mm is sufficient.
12mil is best for low-traffic residential spaces. 20mil provides stronger scratch resistance for busy households, pets, and high-use areas.
Underlay thickness ranges from 1 mm to 12 mm depending on your flooring type. The ideal choice depends on what you are installing:
The "27 rule" is an ergonomic guideline stating that the sum of two riser heights (the vertical step) and one tread depth (the horizontal part you step on) should equal 24 to 27 inches. This formula ensures a natural, comfortable walking stride, preventing steepness and reducing tripping risks.
Common mistakes to avoid during stair carpet installation
Using low-quality carpet that wears quickly in high-traffic areas. Skipping padding, which reduces comfort and lifespan. Poor measurements leading to mismatched patterns or loose edges. Not securing tack strips correctly, which can create safety hazards.
The thicker the carpet underlay is, the more thermal insulation it will provide. To have a real impact on the energy efficiency of your room (and feel the difference in terms of warmth), you'll need to buy a product that measures at least 10-11mm thick.
Stairs need 9mm thickness or less
The most important thing to look out for when fitting underlayment on steps, is the thickness of the product. For it to go neatly round each step, you need to choose a 9mm thickness or less. That's because any thicker than 9mm, then it won't go over the steps neatly.
The 7-11 stair rule is a widely used architectural and carpentry guideline stating that the ideal stair riser (the vertical height) should be 7 inches and the tread (the horizontal depth) should be 11 inches. This ratio mimics the natural human stride, providing maximum comfort and safety.
▪️ Uneven Risers: The height of each step varies, making it difficult and potentially dangerous to climb. ▪️ Narrow Treads: The treads are too narrow, leaving insufficient space for comfortable foot placement. ▪️ Correct (✓): This shows a staircase with consistent riser and tread dimensions.
Yes, 12mm laminate is generally considered better than 8mm for overall quality, stability, and feel. However, the 8mm option is perfectly suitable for low-traffic areas or tighter budgets. The right choice depends on your specific needs, subfloor, and budget.
The 10mm thickness offers a good level of comfort, but not quite as much cushioning compared to a 12mm thick underlay. The 2.4 tog offers a good warmth rating but not quite as high as the Midas 12mm of 3.3 tog.
With that being said, most underlayments are 2-3mm thick, but are sometimes thicker for carpet or to smooth out an uneven subfloor.
Yes, but with limitations. 12mm plywood is acceptable for flooring only when used as a secondary layer, underlayment, or part of a multi-layered system. For structural strength, it is not thick enough to serve as a standalone subfloor in most situations.
12mm is exactly 1.21.21.2 centimeters or ≈0.47is approximately equal to 0.47≈0.47 inches, which is just shy of half an inch. In standard imperial measurements, it is closest to 15/32 of an inch.
To extend the lifespan of your 12 mil wear layer, follow proper maintenance techniques like regular sweeping and vacuuming, prompt cleaning of spills, and using doormats and furniture pads for protection. A properly maintained 12 mil wear layer can last anywhere from 10 to 15 years or more.
Selecting the right underlayment for your 12mm laminate is crucial for optimal performance. The underlayment serves several functions, including providing a smooth surface for installation, acting as a moisture barrier, and offering additional sound and thermal insulation.
The "Rule of 3" in flooring is a design principle that recommends using no more than three distinct flooring materials or color variations throughout your entire home. Limiting your design to three elements creates visual cohesion, prevents a chopped-up layout, and ensures smooth, intentional transitions from room to room.