From European patent No. 0 667 749 to the present applicant there is known a floor covering system comprising a carpet underlay and an upper carpet to be laid on said underlay, said underlay consisting of a core with a nonslip layer, being a layer of glue, present on the bottom side thereof. A membrane is present on the upper side, thus forming an upper layer that is substantially impermeable to glue.

Although said floor covering system has been successfully used for many years, it has now appeared to be possible to improve said floor covering system by forming the upper layer of a readily obtainable, cheaper material and making the core of the carpet underlay more flexible. Extensive research has led to a carpet underlay according to the present invention, which is characterized in that the core is made of a foam-like material and in that the upper layer is made of paper.

From British patent application GB 2,152,875 there is known a carpet underlay for floor covering and a method of manufacturing the same. The carpet underlay comprises a foam layer and a backing layer formed from a creped paper reinforced by weft threads laid in parallel rows on the paper in the direction of the crimp therein. The weft threads are secured to the paper by means of stitches, and the paper is fixed to a foamed rubber layer by means of a layer of glue. This is a relatively complicated carpet underlay.

Further preferred embodiments of a carpet underlay are

disclosed in the subclaims and will be explained in more detail below.

The invention also relates to a method for laying floor covering by first laying a carpet underlay on the floor, with the nonslip layer facing towards the floor, and applying a layer of glue to the upper layer being substantially impermeable to glue of said underlay, on which the upper carpet is then laid, characterized in that a carpet underlay as described above is used.

A smooth surface is obtained by using the carpet underlay, on which a floor covering can readily be laid, without said floor covering exhibiting any wrinkles and/or curvature. Furthermore it is a known fact that a carpet underlay provides a good distribution of forces and a good thermal insulation and sound insulation.

The above objects are accomplished by using polyurethane foam. Furthermore it is possible to make the carpet underlay relatively soft or relatively hard to the touch by using specific kinds of polyurethane foam having a lower or a higher density.

The use of paper for the upper layer makes it possible to simplify the production process and manufacture the underlay at low cost.

Preferably, the paper is a printed crepe paper, in particular crepe paper of 50-75 g/m2, which means that the basic paper has a weight of 50 g/ma, and that the paper has a weight of 75 g/m2 after creping. It will be apparent that also other known crepe papers may be used, and that the values of 50 g/ms and 75 g/m2 are only preferred values, which values may increase by 40-60 wt. % per unit area as a result of the creping treatment of the paper.

The paper upper layer may furthermore be self-adhesive on both sides, one side being covered with a protective layer. After the carpet underlay has been laid, the protective layer may be removed, after which a carpet can be laid directly on the self-adhesive layer.

The invention will now be explained in more detail by means of the following example of the manufacture of a carpet underlay, which example must not be construed as being limitative.

Example.

A thin layer of glue is applied to the upper side of the polyurethane foam underlay core in an amount of 30 g/m2, on which a layer of crepe paper is laid, which crepe paper is preferably provided with a print and has a weight of 75 g/m2. The original paper had a weight of 50 glm2.

A film of glue is applied to the other side of the core in an amount of 25 g/m2, on which a non-woven material is laid, to which a hot melt is applied in an amount of 30 g/m2. Thus an underlay having a thickness of 6.5 mm is obtained.

When floor covering is to be laid, the underlay is laid on a floor with the paper facing upwards. Glue is applied to the paper upper layer, and the upper carpet is laid on said layer of glue.