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Masonry inner leaf mass requirement for external cavity walls
2.38NI-wide·Technical Booklet G Resistance to the Passage of Sound
The masonry inner leaf should have a mass per unit area of at least 120 kg/m2 excluding finish. However, there is no minimum mass requirement where there are openings in the external wall (see Diagram
soundexternal-spaceseparating-wallMasonry inner leaf mass requirement where separating floor present
2.39NI-wide·Technical Booklet G Resistance to the Passage of Sound
Where there is also a separating floor then the requirement for a minimum mass per unit area of 120 kg/m2 excluding finish should always apply, irrespective of the presence or absence of openings.
soundseparating-wallflatsJunctions with internal timber floors
2.45NI-wide·Technical Booklet G Resistance to the Passage of Sound
If the floor joists are to be supported on a type 1 separating wall then they should be supported on hangers and should not be built in (see Diagram 2.10).
soundtimberseparating-wallinternal-floorJunctions with internal concrete floors
2.46, 2.47NI-wide·Technical Booklet G Resistance to the Passage of Sound
An internal concrete floor slab may only be carried through a type 1 separating wall if the floor base has a mass per unit area of at least 365 kg/m² (see Diagram 2.11). Internal hollow-core concrete
soundconcreteseparating-wallinternal-floorConcrete beam floors with infilling blocks
2.48NI-wide·Technical Booklet G Resistance to the Passage of Sound
For internal floors of concrete beams with infilling blocks, beams built in to the separating wall should be avoided unless the blocks in the floor fill the space between the beams where they penetrat
soundconcreteseparating-wallinternal-floorJunctions with timber ground floors
2.49NI-wide·Technical Booklet G Resistance to the Passage of Sound
If the floor joists are to be supported on a type 1 separating wall then they should be supported on hangers and should not be built in.
soundtimberseparating-wallground-floorCavity Masonry Separating Walls - Sound Resistance Principles
2.59NI-wide·Technical Booklet G Resistance to the Passage of Sound
The resistance to airborne sound depends on the mass per unit area of the leaves and on the degree of isolation achieved. The isolation is affected by connections (such as wall ties and foundations) b
non-domesticflatssoundseparating-wallParty Wall Thermal Bypass and Building Regulations Compliance
2.59NI-wide·Technical Booklet G Resistance to the Passage of Sound
Air movement in a cavity masonry separating wall can be a source of significant heat loss. This is known as the party wall thermal bypass and is addressed by Part F of the Building Regulations. Any me
non-domesticflatssoundenergyseparating-wallCavity Masonry Wall Type 2 Constructions
2.60, 2.61NI-wide·Technical Booklet G Resistance to the Passage of Sound
Four wall type 2 constructions (types 2.1, 2.2, 2.3 and 2.4) are described in this guidance. Two of these wall constructions (types 2.3 and 2.4) are only suitable when a step in elevation and/or a sta
non-domesticflatssoundseparating-wallJunction Details for Flanking Transmission Control
2.62NI-wide·Technical Booklet G Resistance to the Passage of Sound
Details of how junctions should be made to limit flanking transmission are also described in this guidance.
non-domesticflatssoundseparating-wallBest Practice Measures for Cavity Masonry Separating Walls
2.63NI-wide·Technical Booklet G Resistance to the Passage of Sound
Points to watch – Do (a) Do fill and seal all masonry joints with mortar. (b) Do keep the cavity leaves separate below ground floor level. (c) Do ensure that any external cavity wall is stopped with a
non-domesticflatssoundseparating-wallProhibited Practices for Cavity Masonry Separating Walls
2.63NI-wide·Technical Booklet G Resistance to the Passage of Sound
Do not (g) Do not try and convert a cavity separating wall to a type 1 (solid masonry) separating wall by inserting mortar or concrete into the cavity between the two leaves. (h) Do not change to a so
non-domesticflatssoundseparating-wallWall ties in separating cavity masonry walls
2.64NI-wide·Technical Booklet G Resistance to the Passage of Sound
The wall ties used to connect the leaves of a cavity masonry wall should be tie type A.
soundseparating-wallmasonryCavity widths in separating cavity masonry walls
2.65NI-wide·Technical Booklet G Resistance to the Passage of Sound
Recommended cavity widths are minimum values.
soundseparating-wallcavity-wallWall type 2.1 – Dense aggregate concrete block with cavity
2.67NI-wide·Technical Booklet G Resistance to the Passage of Sound
Two leaves of dense aggregate concrete block with 50 mm cavity, plaster on both room faces (see Diagram 2.15) – minimum mass per unit area including plaster 415 kg/m2; minimum cavity width of 50 mm; 1
soundseparating-wallmasonrycavity-wallWall type 2.2 – Lightweight aggregate block with cavity
2.68NI-wide·Technical Booklet G Resistance to the Passage of Sound
Two leaves of lightweight aggregate block with 75 mm cavity, plaster on both room faces (see Diagram 2.16) – minimum mass per unit area including plaster 300 kg/m2; minimum cavity width of 75 mm; 13 m
soundseparating-wallmasonrycavity-wallFloor type 1.1C with separating wall types 3.1 and 3.2
3.49NI-wide·Technical Booklet G Resistance to the Passage of Sound
A separating floor type 1.1C base (excluding any screed) should pass through separating wall types 3.1 and 3.2 (see Diagram 3.10).
flatssoundseparating-wallFloor type 1.2B with separating wall type 3 – discontinuity requirement
3.50NI-wide·Technical Booklet G Resistance to the Passage of Sound
A separating floor type 1.2B base (excluding any screed) should not be continuous through a separating wall type 3.
flatssoundseparating-wallFloor type 1.2B with separating wall type 3.2 – joint positioning
3.51NI-wide·Technical Booklet G Resistance to the Passage of Sound
Where separating wall type 3.2 is used with floor type 1.2B 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.
flatssoundseparating-wallSeparating wall type 3.3 – leaf mass requirement
3.52NI-wide·Technical Booklet G Resistance to the Passage of Sound
The mass per unit area of any leaf that is supporting or adjoining the floor should be at least 120 kg/m2 excluding finish.
flatssoundseparating-wallSeparating wall type 3.3 – floor base and cavity requirements
3.53NI-wide·Technical Booklet G Resistance to the Passage of Sound
The floor base (excluding any screed) should be carried through to the cavity face of the leaf of the core. The cavity should not be bridged.
flatssoundseparating-wallFloor type 1.2B with separating wall type 3.3 – joint positioning
3.54NI-wide·Technical Booklet G Resistance to the Passage of Sound
Where floor type 1.2B is used and the planks are parallel to the separating wall the first joint should be a minimum of 300 mm from the inner face of the adjacent cavity leaf of the masonry core.
flatssoundseparating-wallJunctions with separating wall type 3.3 - Leaf mass requirement
3.90NI-wide·Technical Booklet G Resistance to the Passage of Sound
The mass per unit area of any leaf that is supporting or adjoining the floor should be at least 120 kg/m2 excluding finish.
soundseparating-wallseparating-wall-type-3.3Floor joists support on separating wall type 3 – masonry between independent panels
3.127NI-wide·Technical Booklet G Resistance to the Passage of Sound
If floor joists are to be supported by the separating wall then they should be supported on hangers and should not be built in.
soundseparating-wallCeiling junction sealing for separating wall type 3
3.128NI-wide·Technical Booklet G Resistance to the Passage of Sound
The ceiling should be taken through to the masonry. The junction between the ceiling and the independent panel should be sealed with tape or caulked with sealant.
soundseparating-wallFloor voids sealing for separating wall type 4 – timber frames with absorbent material
3.129NI-wide·Technical Booklet G Resistance to the Passage of Sound
Where the joists are at right angles to the wall, spaces between the floor joists should be sealed with full depth timber blocking. Any voids to be filled with flexible caulking.
soundseparating-wallCeiling and wall lining junction sealing for separating wall type 4
3.130NI-wide·Technical Booklet G Resistance to the Passage of Sound
The junction of the ceiling and wall lining should be sealed with tape or caulked with sealant.
soundseparating-wall