SEPARATING FLOORS (NEW BUILDINGS) SOUNDPROOFING

Floating floors (floating layers and resilient layers)

3.62 The floating floor consists of a floating layer and resilient layer. See Diagram 3-11.

3.63 Points to watch

Do

1. Do leave a small gap (as advised by the manufacturer) between the floating layer and wall at all room edges and fill with a flexible sealant.
2. Do leave a small gap (approx. 5 mm) between skirting and floating layer and fill with a flexible sealant.
3. Do lay resilient materials in rolls or sheets with lapped joints or with joints tightly butted and taped.
4. Do use paper facing on the upper side of fibrous materials to prevent screed entering the resilient layer.

Do not

1. Do not bridge between the floating layer and the base or surrounding walls (e.g. with services or fixings that penetrate the resilient layer).
2. Do not let the floating screed create a bridge (for example through a gap in the resilient layer) to the concrete floor base or surrounding walls.

Diagram 3-11: Floating floors (a) and (b)

3.64 Floating floor (a) Timber raft floating layer with resilient layer

Floating floor (a) should meet the following specification:

• timber raft of board material (with bonded edges e.g. tongued and grooved) of minimum mass per unit area 12 kg/m², fixed to 45 mm x 45 mm battens
• timber raft to be laid loose on the resilient layer, battens should not be laid along any joints in the resilient layer
• resilient layer of mineral wool with density 36 kg /m3 and minimum thickness 25 mm. The resilient layer may be paper faced on the underside

3.65 Floating floor (b) Sand cement screed floating layer with resilient layer Floating floor (b) should meet the following specification:

• floating layer of 65 mm sand cement screed or a suitable proprietary screed product with a mass per unit area of at least 80 kg/m2. Ensure that the resilient layer is protected while the screed is being laid. A 20 – 50 mm wire mesh may be used for this purpose.
• resilient layer consisting of either:
  1. a layer of mineral wool of minimum thickness 25 mm with density 36 kg /m3, paper faced on the upper side to prevent the screed entering the resilient layer, or
  2. an alternative type of resilient layer which meets the following two requirements:
     1. maximum dynamic stiffness (measured according to BS EN 29052-1:1992) of 15 MN/m3, and
     2. minimum thickness of 5 mm under the load specified in the measurement procedure of BS EN 29052-1:1992, 1.8 kPa to 2.1 kPa.

Note: For proprietary screed products, seek advice from the manufacturer.

3.66 Floating floor (c) Performance based approach

Floating floor (c) should meet the following specification:

• rigid boarding above a resilient and/or damping layer(s), with
• weighted reduction in impact sound pressure level (Lw) of not less than 29 dB when measured according to BS EN ISO 140-8:1998 and rated according to BS EN ISO 717-2:1997. (See Annex B: Supplementary guidance on acoustic measurement standards.). The performance value Lw should be achieved when the floating floor is both loaded and unloaded as described in BS EN ISO 140-8:1998 for category II systems.

Note: For details on the performance and installation of proprietary floating floors, seek advice from the manufacturer.

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E SEPARATING FLOORS (NEW BUILDINGS)

3.67 Floor type 2.1C Solid concrete slab (cast in-situ or with permanent shuttering), floating floor, ceiling treatment C (see Diagrams 3-12 and 3-13)

• minimum mass per unit area of 300 kg/m2 (including shuttering only if it is solid concrete or metal), and any bonded screed
• regulating floor screed optional
• floating floor (a), (b) or (c) essential
• ceiling treatment C (or better) essential

Diagram 3-12: Floor type 2.1 C(a) Floor type 2.1 with ceiling treatment C and floating floor (a) Picture

Diagram 3-13: Floor type 2.1 C(b) Floor type 2.1 with ceiling treatment C and floating floor (b)

3.68 Floor type 2.2B Concrete planks (solid or hollow), floating floor, ceiling treatment B (see Diagrams 3-14 and 3-15)

• minimum mass per unit area of planks and any bonded screed of 300 kg/m2
• use a regulating floor screed
• all floor joints fully grouted to ensure air tightness
• floating floor (a), (b) or (c) essential
• ceiling treatment B (or better) essential

Diagram 3-14: Floor type 2.2B(a) Floor type 2.2 with ceiling treatment B and floating floor (a)

Diagram 3-15: Floor type 2.2B(b) Floor type 2.2 with ceiling treatment B and floating floor (b)

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SEPARATING FLOORS (NEW BUILDINGS) SOUNDPROOFING

Junction requirements for floor type 2

Junctions with an external cavity wall with masonry inner leaf

3.69 Where the external wall is a cavity wall:

1. the outer leaf of the wall may be of any construction, and
2. the cavity should be stopped with a flexible closer (see Diagram 3-16) ensuring adequate drainage, unless the cavity is fully filled with mineral wool or expanded polystyrene beads (seek manufacturer’s advice for other suitable materials).

3.70 The masonry inner leaf of an external cavity wall should have a mass per unit area of at least 120 kg/m2 excluding finish.

3.71 The floor base (excluding any screed) should be built into a cavity masonry external wall and carried through to the cavity face of the inner leaf. The cavity should not be bridged.

Floor 2.2B

3.72 Where floor 2.2B is used and the planks are parallel to the external wall the first joint should be a minimum of 300 mm from the cavity face of the inner leaf. See Diagram 3-16.

3.73 See details in Section 2 concerning the use of wall ties in external masonry cavity walls. Diagram 3-16: Floor type 2 – external cavity wall with masonry internal leaf

Junctions with an external cavity wall with timber frame inner leaf

3.74 Where the external wall is a cavity wall:

1. the outer leaf of the wall may be of any construction, and
2. the cavity should be stopped with a flexible closer
3. the wall finish of the inner leaf of the external wall should be two layers of plasterboard, each sheet of plasterboard to be of minimum mass per unit area 10 kg/m2, and all joints should be sealed with tape or caulked with sealant.

Junctions with an external solid masonry wall

3.75 No guidance available (seek specialist advice).

Junctions with internal framed walls

3.76 There are no restrictions on internal framed walls meeting a type 2 separating floor. Junctions with internal masonry walls

3.77 The floor base should be continuous through, or above an internal masonry wall.

3.78 The mass per unit area of any load bearing internal wall or any internal wall rigidly connected to a separating floor should be at least 120 kg/m2 excluding finish.

Junctions with floor penetrations (excluding gas pipes)

3.79 Pipes and ducts that penetrate a floor separating habitable rooms in different flats should be enclosed for their full height in each flat. See Diagram 3-17.

3.80 The enclosure should be constructed of material having a mass per unit area of at least 15 kg/m2. Either line the enclosure, or wrap the duct or pipe within the enclosure, with 25 mm unfaced mineral wool.

3.81 Leave a small gap (approx. 5 mm) between the enclosure and floating layer and seal with sealant or neoprene. Where floating floor (a) or (b) is used the enclosure may go down to the floor base, but ensure that the enclosure is isolated from the floating layer.

3.82 Penetrations through a separating floor by ducts and pipes should have fire protection to satisfy Building Regulation Part B - Fire safety. Fire stopping should be flexible and also prevent rigid contact between the pipe and floor.

Note: There are requirements for ventilation of ducts at each floor where they contain gas pipes. Gas pipes may be contained in a separate ventilated duct or they can remain unenclosed. Where a gas service is installed, it shall comply with relevant codes and standards to ensure safe and satisfactory operation. See The Gas Safety (Installation and Use) Regulations 1998, SI 1998 No.2451.

fill small gap with flexible seal

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SEPARATING FLOORS (NEW BUILDINGS) SOUNDPROOFING

Diagram 3-17: Floor type 2 – floor penetrations

For flats where there are separating walls the following may also apply:

Junctions with a separating wall type 1 - solid masonry

Floor type 2.1C 3.83 A separating floor type 2.1 C base (excluding any screed) should pass through a separating wall type 1.

Floor type 2.2B

3.84 A separating floor type 2.2B base (excluding any screed) should not be continuous through a separating wall type 1. See Diagram 3-18.

Diagram 3-18: Floor types 2.2B(a) and 2.2B(b) – wall type 1

Picture

Junctions with a separating wall type 2 - cavity masonry

3.85 The floor base (excluding any screed) should be carried through to the cavity face of the leaf. The cavity should not be bridged.

Floor type 2.2B

3.86 Where floor type 2.2B is used and the planks are parallel to the separating wall the first joint should be a minimum of 300 mm from the cavity face of the leaf.

Junctions with a separating wall type 3 - masonry between independent panels

Junctions with separating wall type 3.1 and 3.2 (solid masonry core)

Floor type 2.1C

3.87 A separating floor type 2.1 C base (excluding any screed) should pass through separating wall types 3.1 and 3.2. See Diagram 3-19.

Diagram 3-19: Floor type 2.1 C – wall types 3.1 and 3.2

Floor type 2.2B

3.88 A separating floor type 2.2B base (excluding any screed) should not be continuous through a separating wall type 3.

3.89 Where separating wall type 3.2 is used with floor type 2.2B and the planks are parallel to the separating wall the first joint should be a minimum of 300 mm from the centreline of the masonry core.

separating wall types

3.1 and 3.2

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