home > our products > carpet underlay
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- introduction
- While undertaking a project to source underlay for distribution in different countries around the World we spent a lot of time researching different underlay markets.
We also visited many PU underlay manufacturing plants to understand the production and quality processes.
We came to an understanding that in each country distributors of PU underlay respond to a different set of market requirements and expectations.
As part of our service we have endeavoured to remove some of the more creative Marketing jargon and simplify the selection process for a high quality range of PU underlay that is manufactured in China and shipped in 40 foot container quantities around the World.
Distributors and wholesalers can then establish a preferred specification with their own point of differentiation and sales story.
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- the purpose of carpet underlay
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1) Extra protection to the carpet - The underlay absorbs a lot of the impact and wear and tear on the carpet from people and furniture. This helps to increase the life of the carpet and maintain its appearance throughout that life. This is especially true where the sub floor is solid and has no means of absorbing impact.
2) A Comfortable floor to walk on – By cushioning any impact on the floor the underlay gives it a more comfortable feeling for people walking, sitting or playing on the floor.
3) Heat insulation - The underlay provides an additional layer of insulation, which not only reduces the loss of heat through floorboards but also reduces draughts or cold that comes up through the floor. However, because the PU underlay is such a good insulator it can not be used with under floor heating. In such circumstances a rubber based underlay needs to be used.
4) Noise absorption - The underlay not only reduces sound in the room itself but also the transference of sound to surrounding rooms.
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- production of polyurethane (pu) underlay
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The better quality PU underlay is made from recycled scrap polyurethane foam from the furniture industry. Because furniture now has to meet stringent international fire standards the foam that has been used has inherent flame retardant properties which are ideally suited for use as a floor covering.
This scrap foam is broken down (chipped) into small pieces then mixed in an adhesive solution to start the rebonding process. The foam mix is then fed into a large cylinder and compressed at temperature to create the required weight and density. The more material that is fed into the cylinder the greater the density of the final product.
The foam log is then peeled (like a wood veneer) into the required thickness of sheet underlay.
The next stage involves covering the surface of the PU roll with the required membranes.
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- key features & benefits of polyurethane (pu) underlay
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In recent years this type of underlay has become increasingly popular for the following reasons;
recycling:
The product is made from recycled scrap polyurethane foam from the furniture industry. At the end of its life the underlay can oncemore be recycled making it a very environmentally friendly product.
value for money:
Because the underlay is already made from a scrap product the cost of production and the energy and resources involved are significantly less than a comparable rubber based product.
lightweight:
With the rolls being so light in weight they are far easier to handle by installers.
exceptional performance:
More than 10 years of experience has testified to the successful performance of this type of underlay in both protecting carpets and helping to maintain their appearance. This material has been proven to recover well from the repeated compression of foot and wheel traffic.
comfort:
The very nature of the composition of the material makes it a comfortable material to walk on.
heat insulation:
The PU underlay is one of the most effective types of underlay for reducing the loss of heat through floorboards and restricting draughts or cold that come up through the floor. This in turn makes heating more effective and economical and improves the carbon footprint of a home.
sound insulation:
The PU underlay also significantly reduces both sound in the room being used and the transfer of sound to surrounding rooms. High Density thick underlays which absorb the greatest amount of energy will generally be the best at reducing impact sound.
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- areas of usage
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over wooden floorboards
PU underlays can be used over wooden floor boards.
over concrete floors
A thicker, denser underlay will provide the necessary thermal insulation and prevent the loss of heat through the underlay and the transfer of cold up from the concrete floor.
stairs
Because carpets installed over stair nosings experience the heaviest wear in the home, a firm thin underlay is preferred to give minimum protrusion and the best long term protection to the carpet.
under wood & laminate flooring
A 3mm thickness higher density (160 to 180kg/m³) underlay is preferred.
under floor heating
PU underlays are not suitable for underfloor heating because they are too effective in preventing the transfer or loss of heat. A poor insulating material such as such as rubber is required for underfloor heating.
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- comfort & durability
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comfort (luxury) ratings
The comfort rating (sometimes shown in stars) represents the subjective view of the supplier on the comfort level and not that of an independent authority. It is not a consistent rating across the supplier base and therefore can not be accurately be used as a point of comparison. The term “luxury” is often used to represent the level of comfort.
By providing a greater cushion, 11mm underlays tend to be more comfortable (luxurious) to walk on than 7mm underlays.
The quality of the sourced PU foam and the rebonding process will also contribute to the level of comfort.
durability/ density
A high density PU Underlay designed for heavy foot traffic, trolleys and wheelchairs will have less give than a low density underlay. Although this tends to make the carpet feel less comfortable (luxurious) it will provide a firmer support to the carpet and minimise movement and rucking over time.
A lower density thicker underlay would have more give and this would be typically used in a bedroom where foot traffic is likely to be less.
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- specifications
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variation in thickness, density & nominal weight
PU underlay material is produced in a variety of thicknesses and densities. The relationship between the thickness and density will define the nominal weight
thickness (mm) x density (kg/m³ = nominal weight (g/m²)
An important consideration for an installer is the weight of the roll. The weight can calculated as follows;
thickness (mm) x length (m) x width (m) = roll weight (kg/roll)
density (kg/m3)
To differentiate from rubber based underlays PU underlay tends to be referred to by its thickness rather than its weight. However, varying densities for each thickness define the area of usage and establish a point of differentiation.
size of rolls
Europe 11m x 1.37m (15.07m2)
Aus/NZ 15m x 1.83m (27.45 m²)
The length and width can be customised according to the requirement of the customer.
relationship between pu thickness/density/nominal weight
nominal weight is shown in the grid in g/m² density kg/m³ Thickness 70 80 90 100 110 120 130 140 160 180 3mm x x x x x x x 420 480 540 7mm 490 560 630 700 770 840 910 980 x x 8mm 560 640 720 800 880 960 1040 1120 x x 9mm 630 720 810 900 990 1080 1170 1260 x x 10mm 700 800 900 1000 1100 1200 1300 1400 x x 11mm 770 880 990 1100 1210 1320 1430 1540 x x 12mm 840 960 1080 1200 1320 1440 1560 1680 x x
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- surface membranes
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PU underlay is increasingly offered with a variety of surface membranes which have different
functions and serve as a point of differentiation between various suppliers.
relative features of the different types of surface membranes
images name improved strength moisture resistant quiet printable recyclable 
non woven √ √ √ √ √ 
PE film √ √ √ √ √ 
crepe paper √ √ 
non woven + PE √ √ √ √ √ 
PE film + scrim √ √ √ √ 
aluminium foil √ √
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- SGS testing
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We use a fully certified SGS test laboratory close to our China office to test our underlay.
Some of the tests required by customers include;
Flammability BS 4790 radius of effects of ignition (hot metal nut test) low or medium radius effect BS 4790
Loss in thickness after static loading BS 4939
Loss in thickness after dynamic pass loading BS 4052
Work of compression after 1000 impacts BS4098
Retention of Work of Compression BS4098
Thermal resistance BS4745:1980 (ISO 5085) : Tog rating Impact
Resistance to cracking BS 5808(A)
Sound insulation
BS EN ISO 140-8 Measurement of Impact sound reduction
BS EN ISO 717-2 Rating of the results of the above test.
All acoustic sound insulation figures are based on impact sound and not airborne sound Ie the noise generated by foot traffic or objects falling on the floor. As a general rule, underlays which absorb the greatest amount of energy (luxury use) will be the best at reducing impact sound.
（attached the SGS report）
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- installation
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Traditional stretch fitting is used in the majority of residential installations.
In this type of fitting the underlay is laid up to the gripper and the rolls then joined together using single sided carpet tape.
Usage of gripper is preferred because the effect of carpet cleaning, which may cause a certain amount of carpet shrinkage, will be prevented by the grippers preventing the carpet pulling away from the walls.
Double stick system is being increasingly used in Commercial environments.
Office and Contract areas such as cinemas and exhibition centres generally require hard wearing firm underlays, which will withstand heavy foot and wheeled traffic.
Double sticking means that the underlay is stuck to the sub-floor with a release adhesive and the carpet is then stuck to the underlay using a permanent adhesive.
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- defining your requirement
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We have the flexibility on 40ft container orders to meet your dedicated specification. We simply need you to tell us:
thickness density size surface membrane sub floor membrane required testing
