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                                               Acoustic  insulation






How to soundproof your property

Part E of the Building Regulations was introduced to improve soundproofing for all new and converted buildings, particularly to separating walls and floors, and to common areas. This is known as Part E or ‘Resistance to the Passage of Sound'. But of course this doesn't  do a lot for the other 99% of us who don't live in recently built homes. So with a view to upgrading existing buildings, let's start by looking at how soundproofing works.

How soundproofing works

The best way to reduce sound is either to block it or absorb it – ideally both. To reduce noise through a wall or floor, a high density sound blocker must be used. The more mass there is in any form of sound blocker the more effective it will be at blocking noise. In combination with a sound absorber this can give very good levels of sound reduction to most walls, floors and ceilings.

Higher density acoustic plasterboard is a fairly cheap sound blocker readily available and when used in layers is will give good levels of sound reduction.

Mineral wool (eg loft quilt) of the correct density and thickness is a very efficient sound absorber and can be fitted in stud walls and between timber floor and ceiling joists, which can then be clad with 2 or more layers of acoustic plasterboard with a skim finish.

A common mistake made by many is to use polystyrene or celotex (polyurethane) type insulation. These materials are good for thermal insulation but very little acoustic value.

As a rule, windows and doors often let in the most noise from outside, followed by roofs and lofts. Adequate loft insulation will help soundproof this area by absorbing some of the noise that comes through the roof.

Even double glazed windows offer little soundproofing. Secondary glazing is the best option – ie fitting additional double glazed windows on the inside with a large space between them and the existing window ( See Haynes Home Insulation Manual)

With all glazing, it is important to ensure that all the panes are sealed and there are no gaps that will allow noise leakage. With doors, a really heavy solid door installed with seals to ensure an airtight seal when closed. Acoustic door seal kits can make a big difference, and door panels can be made thicker by lining with insulation.


External noise measured in decibels (dB)

Noise Type

Loudness (dB)

Leaves rustling

Talking quietly

Background city noise at night

Background office noise

Radio normal volume

Car driven in street

Stereo played loudly – Industrial limit before remedial action must be taken

Road drill at 3 metres

Jet aircraft taking off

Yelling baby

Deafening likely to cause hearing injury in very short time







80+ dB






Information courtesy Soundservice.co.uk

All materials used to sound proof a room will have varying effectiveness at either blocking or absorbing noise. Known as STC ratings (Sound Transmission Class) the higher these ratings the more effective the soundproofing will be. Most normal materials found in the home will have an STC rating even if it is not designed for a specific sound control purpose such as windows, masonry walls and carpets. Insulation designed specifically for noise control will have a measured STC rating as well as additional qualities to make them efficiently insulate against noise pollution.


* Sound absorbing acoustic foams

* Soundproofing mats

* Resilient insulation for floating floors,

* Resilient bars for ceilings and stud walls

* Sound absorbing tiles for ceilings and walls

* Class C sound absorbers for common areas of flats

* Bass traps, diffusers, anti-vibration materials


Download this Step-By-Step photo guide to sound-proofing a stud wall




The above information provided courtesy BRE




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    Secondary glazing

    Where Is It Used?

    • Busy areas where traffic noise is a nuisance - even when double glazing is already fitted ( i.e. Hotels situated just off main roads).
    • Ideal for use in Listed Buildings, Heritage / Conservation areas and period properties.
    • As a cost-effective alternative to replacing your existing single glazed windows.
    • Leasehold / rented properties, where changing the existing windows may be uneconomical.
    • Any property where you are unable to modify the existing external windows.
    • Any window that needs noise reduction and / or draught reduction.

    What Does It Look Like?

    Secondary glazing involves adding an extra slim-line window in addition to your existing windows. Usually they have white frames, but can be painted in any of over 200 RAL colours. Most are made from durable aluminium so they will not rot and require very little maintenance. Aluminium is naturally strong so the frames can be made very slim and unobtrusive.

    Units are often pre-drilled and are easy to install. They are simply fixed to the existing windows or fixed into the window reveal. Secondary glazing can be curved to form arched secondary glazing units.

    The Optimum Air Gap - Simple Yet Effective

    Having a 100mm - 200mm air gap between the secondary glazing and the existing windows (glass to glass) will provide an optimum space for sound and heat performance. The air gap provides an additional barrier, preventing heat and sound from passing through. Deeper systems can be designed  for ‘reveal’ fixing the secondary glazing to give a generous gap. But even with a smaller gap it can still be very effective.

    Choosing Glass Thickness

    When installing secondary glazing for sound proofing it’s best to use a different thickness of glass in your secondary glazing than that of the glass in your existing windows. Different thicknesses of glass will help to block different wave lengths of sound, this effect is called the resonation factor. For maximum sound reduction special ‘Stadip’ acoustic glass can be used which is 6.8mm thick. Or less expensive 6.4mm thick ‘laminated’ glass can also offer a significant noise benefit.

    Coatings on Glass for Better Heat Insulation

    Adding well fitted secondary glazing with ordinary 4mm glass will give significant benefits in energy saving and reducing heating bills. However, by specifying ‘K’ glass which has a special heat reflecting coating, gives an extra improvement over un-coated glass and helps to retain heat in the room.



      Most systems use painted aluminium outer frames, sometimes fitted to softwood or hardwood surrounds. Aluminium frames have a slim-profile suitable for fitting within the beading of a typical sash window, so that window sills and shutters can be retained. Beefier, more sophisticated systems comprise a timber sub-frame into which opening casements or sliding sashes are fixed. Individual glazed windows can be hinged so that they fold up like shutters or operate like sash windows.

      The operation of curtains and blinds should be unaffected, and apart from occasional dusting or light cleaning secondary glazing should be virtually maintenance-free.





    Horizontal Sliding

    Horizontal sliders are perfect for insulating casement windows, hinged windows, or any window with vertical bars. Panels slide within the frame allowing easy access to the existing outer windows and to provide ventilation without interfering with curtains or blinds. There can be anything from 2 to 5 panels running on glide-pads, or rollers for larger windows. Most panels can be easily removed by lifting into the head frame and swinging them out.


    Vertical Sliding

    With vertical sliding systems, the 2 ‘sash’ panels slide up and down within the frame. Suitable for traditional wooden box sash windows, or any windows that have horizontal bars. Panels slide open in the same way as vertical sliding sash windows and provide easy access to the existing window. When open they provide ventilation without interfering with curtains or blinds. Spring balances can hold sliding sashes in an open position but some systems with spring catches can be tricky to operate and are only suitable for very small windows. Tilt-back vertical sliding systems allow the sashes to hinge inwards for cleaning. Restrictor stays and braking mechanisms can be fitted to prevent sliding when open.



    Hinged casements are available in single or double leaf format. Suitable where the whole window is to be covered to achieve a large ‘invisible’ secondary unit. Also used for more complex areas such as bay windows. Hinged systems allow quick and easy regular access is required for maintenance, ventilation or cleaning, or means of escape.

    These work well for large panes, with high compression seals for optimum noise insulation and minimise airflow. Multi-point locking can provide enhanced security.

    These styles are suitable where regular ventilation is required.

    Butt hinged units open to around 150 degree giving a large clear opening for full access to the existing windows. Friction hinged units open to around 65 degrees and allow the panel to be held in any given position between the maximum and minimum opening for controlled ventilation, or stays can be fitted to hold windows open. Can be combined with ‘Lift Out’ units for special applications.


    Lift Outs & Removable Panels

    Used to insulate large areas of clear glass without being visible from outside. The large glass panels can be lifted out of the frame for cleaning or to provide ventilation.

    These are best used for windows that are fixed or seldom opened and where access is only occasional necessary for cleaning. They are also useful for windows of unusual shapes. It helps if you have somewhere to store temporarily removed glazing.


    A simple, inexpensive DIY alternative can be made by cutting Perspex sheets which are secured with magnetic strips. These lightweight panels are easy to remove. Magnetic strips fitted to the Perspex  combine with opposite magnetic strips fitted on the edge of the window frame to hold the panel in place.




    Fixed panels are useful where access isn’t required, or in combination with other opening panels. There is no opening mechanism or subframe and is simply face fixed directly onto the existing windows, hence no access (unless completely removed). These are relatively inexpensive and easy to fit as well as being very slim (20mm wide). Ideal for historic buildings as the system is easily ‘reversible’ being fixed by discreet clasps bedded in small pre-drilled countersunk holes. Also useful for leasehold properties where changing the existing windows may not be possible.

    Careful consideration needs to be given to how gain access to the glass and the cavity for periodic cleaning.



    Units of different types can be coupled together to create combination units, such as hinged and lift out panels. This allows complicated window styles, such as a top lights over a fixed window, or hard to treat areas in tight spaces, such as bay windows or large fixed windows.



    The use of external ‘secondary glazing’ to protect historic windows using either glass or plastic sheet is referred to as ‘storm glazing’. This is sometimes used to protect valuable stained glass.


    Source   https://www.duration.co.uk/



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