Sound advice and SI.9 – PART 1
By Bregs Blog admin on 6th October 2014
Many of the homes and apartments constructed in recent years have very poor sound insulation between homes. Anyone looking at discussion boards or homeowner and tenant websites will see that this is a widespread problem that is very expensive to remedy.
This is another fallout of ‘self certified’ poorly constructed homes which impacts directly on families. It can cost €1,300-1,500 per room to upgrade a poorly constructed party wall (see DOELG RIA link here).
The Irish Concrete Fedaration give advice to consumers on buying a home (see link here- for list of helpful FAQ’S see section following this post). Quote:
“Another major problem in some modern houses is poor sound insulation between adjoining properties. The best way to check when buying, is to get a friend or partner to open and close doors and presses in the adjoining property and if possible bring a small radio to check for sound transmission. The builder may or may not be happy to facilitate you, but this is the best way to check for soundproofness. Normally, there will be a certain amount of sound transmission between party walls, but it is important to satisfy yourself that the level of sound transmission is acceptable to you”
This advice from the building industry fails to mention that builders, designers and Certifiers who have a legal responsibility to build party walls and floors to the correct standards. Prospective buyers should not be bringing friends and radios to view properties- they should be provided with a testing certificate from a competent technician confirming that it has been properly built.
The DoE estimate that proper testing of compliance for Part E would cost €800-€1,050 per unit, see information here (page 10) .
Under the new Building Control (Amendment) Regulations Assigned Certifiers will be factoring these additional testing costs into their certification fees.
Blog Note: The cost for the above test has not been factored into previous cost estimates for SI.9.
Other posts of interest:
The following is a list of FAQ’ s off the Irish Concrete Federation – (off website dated 6th October 2014). Please consult with your representative organisation with any queries regarding any of the comments below. Link here:
What are the most important things to consider when building or buying?
The house should be as safe as possible for you and your children to live and sleep in. A house with is constructed from incombustible materials and with the minimum of cavities in the structure (through which flame and hot gasses can pass) is the safest structure. This is particularly important in the case of apartments.
Another major problem in some modern houses is poor sound insulation between adjoining properties. The best way to check when buying, is to get a friend or partner to open and close doors and presses in the adjoining property and if possible bring a small radio to check for sound transmission. The builder may or may not be happy to facilitate you, but this is the best way to check for soundproofness. Normally, there will be a certain amount of sound transmission between party walls, but it is important to satisfy yourself that the level of sound transmission is acceptable to you. Remember, when buying and apartment, the source of the sound may be from above and below as well as through walls with adjoining neighbours. It is important in apartments that vibration from washing machines and spin dryers does not cause irritation.
Is concrete a cold material?
We are all familiar with the cold sensation of stepping onto a concrete surface. However, this is because most concrete surfaces are not insulated. Concrete is efficient at retaining heat and this is why it is often used in storage heaters. Under the Irish Building Regulations floors and walls are now required to be highly insulated and as a result concrete will thermally outperform the most commonly used alternative materials.
Should I build internal walls in concrete block?
Building internal walls in block is relatively inexpensive and has a positive effect on the fire, sound and thermal performance of a house. Applying curtain rails and fixtures is easy and internal block walls can also be used to support Precast concrete floors.
Should I use dry-lining or wet plaster?
Many builders and plasterers opt for dry-lining which is taped at the joints, or plaster slabs and a wet hardwall plaster skim finish. These finishes are generally very acceptable. However, a wet plaster finish, although more labour intensive is arguably a better finish. A wet plaster finish gives improved thermal performance (see thermal mass) and a more solid feel to the building. Ultimately, this is a matter of choice and of course the key to good plaster work is a good plasterer.
What insulation should I use?
There are a wide range of insulation materials on the market, including mineral wool type insulations such as ‘Glasswool’ or ‘Rockwool’ and rigid insulations such as Polyurethane (PU) and High Density Polystyrene (HDPE). Non-rigid insulations are generally used for insulating attics. Where fire performance is concerned, ‘Rockwool’ has far greater fire resistance than ‘Glasswool’ and is considered incombustible.
Where masonry construction is concerned, there are a range of options in relation to wall type. To view the five most typical wall constructions download Thermal Insulation -ERG (Brochure) Click here
Rigid insulation boards can be installed either within the cavity wall or on the internal face of the inside block. Some of the rigid board insulations are foil-faced to reflect radiant heat back into the room. With the higher insulation requirements under the new Part L (Thermal Insulation) of the Building Regulations 2003, using combined in-cavity and internal wall insulation is an increasingly popular choice. This form of construction is likely to become more popular with the introduction of higher thermal performance requirements under new Building Regulations to be implemented towards the end of 2007. It is proposed that thermal insulation requirements will be revised upwards again in 2010.
Specially manufactured plasterboard with rigid insulation board bonded to the back is available for installation on internal walls. This is fixed to the wall with plaster dabs by what is commonly referred to as ‘the slab and dab method’. When rigid board, partial fill, cavity insulation is installed, a clear air space of 40mm should be left between the outside face of the insulation and the inside face of the outer block. To maximise thermal performance, there should be no gaps between the insulation boards and the boards should be fixed tightly against the block inner leaf.
Full-fill cavity insulations are available in both rigid board and bead forms. Full-fill rigid boards are installed as the wall construction progresses whereas, bead insulation is pumped into the cavity after the wall is completed. There are regional preferences for both rigid and bead type insulations. Full-fill insulations breech the cavity wall and therefore should be installed strictly in accordance with manufacturer’s instructions.
Where hollow block construction is used (mainly in the greater Dublin area) rigid insulation (generally foil-faced polyurethane) is fixed to the internal face of the wall.
What is thermal mass?
Thermal mass is a word used to describe materials in a building’s construction which can store and release large quantities of thermal energy. These materials are normally the dense structural elements that form part of the building’s fabric. Materials such as concrete, brick and stone are particularly effective. Concrete blocks exposed to large areas of south-facing glazing, can store free energy from the sun at peak times and return the energy to the room over a period of hours (up to six hours) when the sun has gone down. Increasingly, architects design houses strategically to take advantage of this principle.
What about ventilation?
Until recently the Building Regulations called for permanent ventilation in each room. A new variation in the regulations allows for ‘hit and miss ventilation’ to be included in each room, so that the option for the occupant to temporarily close off the ventilation is available. Ventilation can take the form of vents through the walls or alternatively ‘hit and miss vents’ installed into window sashes. Mechanical ventilation is required in wet areas such as bathrooms.
One of the main methods of improving thermal performance in dwellings is to reduce ‘air filtration’ through the fabric of the building and through the opening and closing of windows and doors and through open chimney flues. A modern house will typically have five or six air changes per hour, but some consider that this is wasteful since expensive heated air is being expelled from the building. There is some debate about this, since air change through both planned and unplanned ventilation is related to ‘indoor air quality’. A certain amount of air change is necessary and some argue that air changes of as little as 0.5 air changes per hour is sufficient. However, this can depend on other factors such as the level of relative humidity and the presence or absence of carpets for example. Generally speaking, it is not good to have very high levels of airtightness in houses which are carpeted throughout. It has been shown that wooden floors harbour as much as fifteen times fewer ‘allergens’ than carpet floors. Allergens are one of the main causes of asthma and Ireland has the fourth highest level of asthma per capita in the world.
Given Ireland’s commitment to the Kyoto agreement, it is likely that air-filtration levels will be reduced further. A partial solution lies in the installation of mechanical air-heat exchange ventilation systems. However, these systems are relatively expensive, difficult to install and require maintenance.
Air filtration through chimney flues can be reduced by the installation of a chimney ‘damper’ or by the installation of a ‘balloon’ while the chimney is not in use. Another method (suitable for new buildings) is to install an under-floor air supply to the fire ope so that cold air to feed the fire is drawn from the outside of the building rather than warm air from the inside of the building. This has the effect of reducing air filtration from the open fire from about 40 litres per hour to about 20 litres per hour – a significant saving.
Another trend is to replace open fires altogether and replace them with wood stoves. This also greatly reduces air filtration. Wood stoves typically yield 80% or more burning efficiency compared to open fires which are approximately 15% efficient. However, some people view the option of lighting a fire in an open hearth as top of their wish list.
Do I need a radon barrier?
Radon is a naturally occurring radioactive gas which originates from the decay of uranium in rocks and soils. When inhaled in sufficient quantities over a protracted period of time radon can be seriously damaging to your health.
Since July 1998, every new house is required to incorporate some degree of radon preventive measures at the time of construction in accordance with the revised Building Regulations. The degree of protection required is dependent upon whether or not the site is located within a High Radon Area.
Technical Guidance Document C of the 1997 Building Regulations, which came into force on the 1st of July 1998, sets out radon preventative measures to be applied in the construction of new dwellings or long stay residential buildings. Click here to download Part C of the Technical Guidance Documents
Two levels of protection are laid down: a basic or precautionary level which applies to new buildings in all parts of the country and a more advanced level which applies to new buildings in designated High Radon Areas. Comprehensive advise on the threats posed by Radon gas and the measures to deal with it are given on the website of the Radiological Protection Institute of Ireland
If I use concrete upper floors do I need soundproofing?
Soundproofing refers to both ‘airborne’ and ‘impact sound’. The level of sound insulation offered by a concrete upper floor is related to the thickness and density of the concrete. Poured or (in-situ) concrete floors have no joints and therefore offer a high level of sound insulation. Precast concrete floors also offer high levels of sound insulation, but care must be taken to fill all joints between the concrete planks and to fill all joints between the floor and the wall. Failure to fill joints between units and the joint between the floor units and the walls will allow ‘flanking noise’ to occur between upper and lower floors.
In order to reduce impact sound to an absolute minimum, it is advisable to install a special rubber layer on top of the floor. This may not be necessary if carpet/carpet underlay is used as the upper floor finish.
Is there a solid block wall between my neighbour and I?
Where houses are constructed using masonry construction, a 215mm solid block ‘party wall’ will separate adjoining houses. To function properly, all the joints must be filled and a coat of wet plaster must be applied on both sides of the wall. Particular attention should be paid to the joint between the concrete party wall and the underside of the roof finish. The Irish Concrete Federation strongly recommend the use of specialist fire stopping such as ‘Firebar’ at this junction.
Where timber frame construction is concerned, it is common practice to use timber studs between adjoining houses and apartments. In the view of the Irish Cocnrete Federation this is a mal practice, since standard timber frame party walls have not been tested to comply with British Standard BS476 part 20 and therefore (de facto) do not comply with the current Irish Building and Fire Regulations.
Can I use precast floors at ground floor level?
The use of precast floors at ground floor level has become popular in recent years because of ease of installation and because of poor ground quality or sloping sites. Some precast flooring suppliers manufacture special ground floor precast units with insulation fixed to the underside of the units.