ABBE Level 3 Diploma in Domestic Green Deal Advice 6. Building Fabric - Advice Presented by [Name] ① Insulation Materials
⑥ Solid Wall Insulation
② Loft Insulation
⑦ Draught-Proofing
③ Insulation at Rafters
⑧ Energy-Efficient Windows & Doors
④ Flat Roof Insulation ⑤ Cavity Wall Insulation
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The Measures
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Insulation Materials
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Insulation Materials Insulation is often the cheapest and most affective solution to heat loss in the home. Insulating the building envelope will allow the reduction in the U-values for the specific building elements: • Roof • Walls • Floor The energy bills and burden on the occupier will be reduced by not having to continually renew the heat inside the dwelling, making insulation an effective way to save energy.
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Types of Insulation Material There are different types of insulation available to insulate the home. Common types of insulation are: • • • • • •
Air-based Foam Foil Aerogel/ Nano gel Recycled cellulose Thermal linings
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Air-Based Insulation Air-based insulation works primarily by trapping air. Mineral wool is the most commonly used insulation of this type: • e.g. rock wool, stone wool, glass wool, glass fibre
However there is also a range of natural materials that work in the same way: • e.g. sheep’s wool, hemp, cellulose All are available as quilt, batts or blown fibre.
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Air-Based Insulation Air-based insulation products are available in rolls of different widths and thicknesses for quick and simple DIY installation - for example, between the: • Rafters in a roof; or • Joists in a ceiling or floor. It can also be produced as lightweight 'slabs' for installing into the cavity walls when building new houses. Loose mineral wool can also be used to fill cavity walls, and is blown in through a hole drilled in the wall after it is built.
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Cellulose Cellulose is perhaps the best example of recycled material use in insulation. Most cellulose insulation is approximately 80% post-consumer recycled newspaper by weight; the rest is comprised of fire retardant chemicals and, in some products, acrylic binders. The biggest long-term performance concern with cellulose insulation is possible loss of fire-retardant chemicals. Because borates are water-soluble, they can leach out if the insulation gets wet.
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Damp spray cellulose
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Foamed Insulation The alternative to air-based insulation materials is foamed insulation. Foamed insulation can perform significantly better than air based insulation, but generally has a higher capital cost. High performance insulation boards There are four common types: • Polystyrene expanded/extruded • Polyurethane • Phenolic insulation • Polyisocyanurate
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Phenolic insulation
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Foamed Insulation Expanded polystyrene foam (EPS) is usually white. Some new innovative EPS products are grey due to the inclusion of graphite, which substantially increases the insulation performance. EPS is safe, nontoxic and inert. The most important properties of EPS are: •
• • • • •
Excellent thermal performance & high compressive strength Outstanding impact absorption Low weight Imperviousness to moisture 100% recyclable Commonly used as insulation to floors, walls and roofs. Also used in bead form for loose fill applications.
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Foamed Insulation All 4 foam insulation materials are available as rigid foam sheets or as a spray-on product. Benefits: Foam insulation provides a number of benefits over other types of insulating materials. It has a relatively high R-value per inch, and can insulate effectively in small spaces. It is also easy to cut and install, and does not produce itchy fibres like those in fiberglass batting. Foam also tends to hold its shape over time, so fewer gaps form where air can leak through. Drawbacks: It is one of the most expensive insulating materials, especially when compared to fiberglass. It is not fireresistant, and must be covered by drywall to reduce fire risk.
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Foamed Insulation Rigid Foam - Uses • Existing solid wall • New build cavities • Ceilings or on top of roof sheathing • Pitched roofs. • Footers and foundations (used to keep cold air from reaching the basement or floor slab)
Spray Foam – Uses • Loft insulation • Existing wall cavities (the foam quickly expands to fill the entire space)
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Spray Foam Insulation Polyurethane insulation is also available as ‘spray foam’. This is most commonly encountered as insulation for hot water cylinders but may also be used to insulate walls or roofs.
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Multi-Foil Insulation Multiple low emissivity surfaces separated by foam. To be effective, the outer layers must face an unventilated cavity.
Performance achieved is controversial – generally recommended to be used with conventional insulation. Local Authority Building Control guidance indicates that a maximum resistance of 1.7 m2K/W should be used in U-value calculations for this.
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Multi foil insulation
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Thermal Linings Thermal Linings are a thin material specifically developed for energy conservation up to 10mm. It is a remarkable material which, when applied inside the property on external walls, reduces heat loss resulting in warmer rooms. Thermal Linings: • Can be used in all residential properties flats, houses, bungalows and mobile homes • Can be applied inside the property on external walls and ceilings • Provides a warm surface to combat condensation • Provides sound insulation as well as outstanding thermal properties Domestic GDA Training – 6. Building Fabric
Aerogel
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Insulation Materials
This table shows the thickness of each material that is required in order for them to achieve the same U value of 0.2W/m2 .
Illustration courtesy of the Architects Journal
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Loft Insulation - Advice
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Loft Insulation Loft Insulation increase 0 to 270mm
Loft insulation increase 100 to 270mm
Savings per annum
Up to £180
£30
Installation cost
£100 to £350
£100 to £350
Pay back time
Up to two years
From four years
C02 per annum
720kg
110kg
Heat rises, and in an un-insulated home a quarter of heat is lost through the roof. Insulating the loft, attic or flat roof is a simple and effective way to save waste and reduce heating bills. Loft insulation is effective for at least 42 years, and it will pay for itself over and over again in that time.
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Installation Installer Requirements/DIY Practicalities Loft insulation is a excellent EEM if it can be effectively installed, but there are several issues to be considered, if the installer is to maximise the benefits of the installation for the customer. These include: • • • • • •
Loft access Loft condition Infestation Avoiding fire hazards What is in the loft Using the loft as storage after the installation
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Installer Requirements: Loft Access Hatch size • On the rare occasions where the loft hatch is not big enough to get the insulation into the loft, a new loft hatch can be created at an additional cost by a professional installer.
Hatch in a dangerous location • There will be times when the loft hatch is in a place that is unsafe for the GDA to access; this may not be the same for the installer who will have specialist equipment and appropriate safety equipment to be able to complete the job on most occasions. • The GDI must also comply with relevant heath and safety legislations, e.g. • The Work at Height Regulations 2005 (as amended) • Safe use of ladders and stepladders - An employers’ guide The DIYer must be competent to undertake the job and be aware of all of the potential risks involved.
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Installer Requirements: Condensation Condensation accumulates when humid air makes its way into the loft and condenses on the underside of a cold roof.
The problem can be so bad that in many cases, it is assumed that a leaking roof has caused the problem. Condensation can saturate roof timbers, give rise to mould and fungus growth, and compromise the roof structure, and – in extreme cases – soak into loft insulation reducing its effectiveness and causing water stains on the underside of the ceiling.
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Condensation
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Installer Requirements: Ventilation
A ventilation path of at least 25mm in width is required between the insulation and the underside of the sarking. Holes and gaps in the ceiling should be sealed to restrict the amount of moist air entering the roof space. For roofs over 35o pitch, or over 10m span, ridge ventilation is required equivalent to a continuous 5mm gap. The traditional ‘cold roof’ or ‘loft’, found in the vast majority of existing buildings, handles moist air from inside the building by allowing it to diffuse through the ceiling into the roof void from where it is removed through cross ventilation.
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Installer Requirements: Condensation The latest Building Regulations summarises best building practice as "build tight, ventilate right". This refers to ensuring that all openings to the outside of the building are closed up to ensure heat conservation, whilst providing ventilation is present at points of moisture production, such as bathrooms kitchens and lofts Insulation stops heat escaping from living spaces, making the loft colder - which could make existing damp or condensation problems worse. You should seek professional advice before installing insulation, to find the best solution to the damp problems first.
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Ventilation: Common Issues Common ventilation issues that the installer should consider include: • Blocking of existing ventilation due to insulation being pushed into the eaves, preventing air flow. • Inadequate ventilation due to under-ventilation after insulation is topped up/installed. • Loft storage blocking the flow of air to parts of the loft, preventing air circulation.
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Installer Requirements: Infestation Scurrying and scraping noises from the attic are also a strong indication that rodents or other wildlife have taken up residence in the roof space. The first step is to inspect the attic and look for visible signs of habitation, the most common of which are droppings. The most common infestations are: • Mouse/Rat • Squirrel • Bird • Insect • Bat All these infestations will have to be resolved before an installation takes place; a specialist pest control company would be best placed to deal with the issues.
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Infestation: Bats Bats are protected as an endangered species in this country, and it is an offence to try to kill or remove bats or to change or block their roosts.
Even if bats have left the attic, it is still an offence to block the roost: bats return to the same place every year and so even empty bat roosts are protected. If a homeowner is aware that bats are in their attic, they should consult with the Bat Conservation Trust before carrying out insulation, remedial timber treatments, insect control or rodent control that may cause harm to bats.
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Infestation: Bees Protected Species are as designated by the Wildlife and Countryside Act 1981 and in the case of insects by Schedule 5 of the Act.
Neither honey bees, bumble bees or any other species of bee is included as a protected species or offered any protection as a protected species.
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What’s in the Loft? In many lofts there are obstacles which will need addressing before an effective installation can take place, such as: • • • • • •
Storage Boarding Water tank Pipes Cables Spot lights
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Storage/Boarding Insulation depth
Thermal resistance
270mm
6.11m2 k/W
100mm
3.09m2 k/W
Compressing insulation after it has been fitted will degrade its thermal efficiency, by up to 50% and increase payback times, as a large part of its insulant value comes from the air trapped within the fibres.
However, it is possible to arrange for joists to be extended and floor boarding to be fixed to help maintain the storage area. If you already have a boarded area of no more than a third of the loft area the installers will work around it and leave it uncovered.
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Pipes/Tank Any company who carries out loft insulation is responsible for insulating any tanks and pipework that are in the roof space to ensure they do not freeze during the winter.
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Cables A cable that feeds a shower unit is usually a 30amp. The installers will identify this and make sure this cable is not covered by the insulation, by either laying the cable on top if there is enough flex, or leaving a gap in the insulation around the cable to ensure it does not overheat. Other cables in the loft tend to be lighting cables, which are less affected by the insulation derating them.
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Recessed Lights The installers will cut the insulation away from recessed lights, leaving a gap of approximately 2” around the lights to prevent overheating. Alternatively, An Intumescent Downlight Cover can be fitted.
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Existing Loft Insulation Existing insulation can be left in the loft and an additional layer added to it to bring it up to the required minimum thickness. It does not matter how long the existing insulation has been in the loft; it still retains its insulant value, providing it has not been compromised.
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Loft Insulation: Cost
Rockwool vs. Sprayfoam for lofts Domestic GDA Training – 6. Building Fabric
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Loft Insulation: Summary There are four basic types of insulation used in insulating lofts: • • • •
Air based Loose fill Blown insulation Ridged board
Air Based will be used for the default calculation in the Occupancy Assessment
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Insulation at Rafters - Advice
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Insulation to Sloping Ceilings Where there are rooms in the roof, insulation can be added to the sloping ceiling areas either: • Between the rafters; and/or • Above or below the rafters. The best option depends on what other work is required to the roof (if any).
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Insulation to Sloping Ceilings Insulation between the rafters is the most straightforward to install, and avoids any loss of room height.
(Diagram shows a section through the sloping ceiling looking up or down the slope)
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Ventilation space limits insulation thickness – air gap must be at least 50mm
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Insulation to Sloping Ceilings Breathable sarking membrane
Ventilation space can be reduced but not eliminated if a breathable membrane is present.
Alternatively, an additional set of battens can be fitted along the top of the rafters so that the insulation thickness can equal the rafter depth. (The diagram shows a section through the sloping ceiling looking up or down the slope.)
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Insulation to Sloping Ceilings Due to: • The need to maintain the ventilation space • The cold bridging effect of the rafters; and • The fact that the rafters are rarely more than 100mm deep It is usually necessary to add an additional layer of insulation above or below the rafters to achieve a reasonable target U-value.
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Insulation to Sloping Ceilings Sarking Insulation If insulation is added above the rafters, it is sometimes known as ‘sarking insulation’.
(Diagram shows a section through the sloping ceiling looking up or down the slope.)
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Room in Roof Issues If a ‘Room in Roof’ (RIR) is not heated from the fixed heating, the DEA software will assume portables (which will be more expensive). Ventilation will need to be maintained in a residual area when insulation is topped up; cross flow ventilation may need to be installed. Insulation in RIR may not be appropriate even if the software has specified it, for example due to access issues. Stud walls within the RIR the stud walls will need to be insulated to the required standards 0.25w/m2k for all elements, around about 210mm with mineral wool or 100mm with foil faced foam insulation.
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RIRs not identified in RdSAP If the RIR has been identified as being outside the RdSAP methodology, e.g. no staircase: • The software will underestimate the heating needs for the property. • The software may also make an inappropriate insulation recommendation.
These issues will put finance for the unidentified RIR beyond the scope of GD funding.
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Flat Roof Insulation - Advice
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Flat Roof Insulation Flat roof insulation is often done when the roof covering is being replaced. Insulation may be installed above or below the existing “deck”.
• A “cold roof” or “cold deck” has the insulation below the existing “deck”. • A “warm roof” or “warm deck” has the insulation above the existing “deck”. • An “inverted roof” has the insulation installed above the waterproof covering.
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Cold Roof (or Cold Deck) Alternatively insulation can be installed between the joists, although this is less effective due to the cold bridging due to the joists. A ventilated air space of at least 50mm should be retained above the insulation waterproof. Waterproof covering on roof deck Insulation between joists Plasterboard
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Cold Roof (or Cold Deck) If the reduction in room height is not a problem, insulation can be installed below the roof joists. The air space between the joists should be cross-ventilated to avoid any risk of condensation. Waterproof covering on roof deck Joists Insulation Plasterboard
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Warm Roof (or Warm Deck) In a warm roof, the insulation is installed above the roof deck but below the waterproof covering. This is usually considered to be the best option as it eliminates any risk of condensation but is only cost effective when the roof covering is being replaced. Waterproof covering Insulation Joists Plasterboard
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Inverted Roof (or Inverted Warm Deck) In this case the insulation is installed above the waterproof covering, avoiding the need to disturb the existing roof structure. It may also prolong the life of the waterproof covering. However, rainwater penetration may reduce the thermal performance of the insulation. Gravel or other ballast Insulation Waterproof covering Joists Plasterboard
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Insulation to Flat Roofs
Measure
Annual Saving
Installation Cost
CO2 saving per Pay Back Time year
Flat roof
£180
£3500
800kg
19 years
Installing flat roof insulation could save you around £180 and 800kg of carbon dioxide a year If half your roof area is flat - the savings will vary depending on how much of the property has a flat roof.
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Cavity Wall Insulation - Advice
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Cavity Wall Insulation If a house was built after 1920, the chances are that its external walls are made of two layers with a gap or cavity between them. Cavity wall insulation fills that gap, keeping the warmth in to save energy. It can also help reduce condensation inside the house if this is a problem.
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Cavity Wall Insulation Houses with cavity wall insulation have the following benefits: • • • • •
Reduced fuel bills. A warmer house that stays warmer longer. Reduced condensation. Fewer draughts. Benefits to the environment.
Cavity wall insulation can reduce the heat loss through cavity walls by up to 40 per cent. It can also lead to reduced heating costs and improved comfort levels.
Payback (savings against costs) times are estimated at 2 to 3 years. Domestic GDA Training – 6. Building Fabric
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Cavity Wall Insulation Cavity Wall Insulation is a simple process by which insulation is injected into this cavity through a carefully designed pattern of holes. There are a number of different products, or systems, each of which must pass stringent technical requirements laid down by the British Board of Agrement (BBA) or alternative independent approvals body All systems are "fit and forget" and require no servicing, maintenance or adjustment. Cavity Insulation Guarantee Agency CIGA has registered installers, and offers Guarantees for, all 3 products for 25 years. • • •
Mineral wool Polystyrene bead Foam
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Cavity Wall Insulation: Materials Mineral Wool Mineral Wool insulation is a cotton wool like material produced from either rock wool or glass wool, and is used in the majority of installations. Polystyrene Bead Bead is made up of small expanded polystyrene beads normally injected with a binder. Foam Urea Formaldehyde cavity wall insulation was introduced into the UK in the late 1960's and involves the injection of a water based chemicals system that produces an insulating foam in the cavity. Polyurethane foam is now used as both a cavity insulation material and wall stabilisation material where the wall ties have failed, as an alternative to wall tie replacement. However, where work is carried out purely for thermal insulation purposes either mineral wool or polystyrene beads would normally be used.
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Installer requirements Is the House Suitable for Cavity Wall Insulation Before the installation, the installing firm will undertake an assessment of your property to confirm that it is suitable for insulation. This assessment may be undertaken by a surveyor or the Technician before installation using a boroscope.
How long does it take Cavity wall insulation normally takes around two hours to install, but the time does depend on the size of the house and other factors, such as access. What about filling the holes All the holes through which the insulation is injected are filled with mortar to match the existing colour and texture as closely as possible. On pebbledash finishes, pebbles are added to the surface to match the existing finish. After weathering, the holes are difficult to see. Access Site access will also be needed for the installer equipment usually they will need to be able to park a lorry. Scaffolding may be required to access difficult to reach areas around the property, over extensions, conservatories, garages etc.
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Potential Savings Measure
Annual Savings
Insulation Costs
Payback Time Co2 per year
Cavity wall insulation
£150
£500 - £1000
Less than 5 years
Around 550kg
These are estimated figures based on insulating a gas-heated, semidetached home with three bedrooms.
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Cavity wall insulation 6 million homes in Britain have now had cavity wall insulation installed, it's the smart way to save money. The Government regards cavity wall insulation as one of the most effective energy savings measures that people can carry out on their homes and apart from saving money it's a major contributor to reducing emissions External walls account for 35% of heat loss from the average house, and studies suggest that every square metre of Cavity Wall Insulation will save more than a tonne of Carbon Dioxide over the average life of the building. For a semi detached house with an external wall area of 80m2, this equates to savings of 80 tonnes or more. The insulation present in a filled cavity reduces this heat loss, making the house warmer or reducing the amount of fuel required to maintain a comfortable temperature. Domestic GDA Training – 6. Building Fabric
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Reasons Not to Install Issues that might impact on installation • • • • • • • • •
Rain penetration/severe exposure Access issues Narrow cavities Blocked cavities First floor properties Partially filled cavities Poor pointing/cracked render Cladding or render Cost
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Reasons Not to Install Air bricks and flues Air bricks maintain ventilation to the under floor area, lofts, kitchens and bathrooms. To prevent condensation and reduce damp within the property. Properties with a cavity built before 1995 may not have had a cavity sleeve fitted; this can be addressed by the installer so the insulation material does not block the flow of air. Care should be taken to avoid cold bridging.
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Reasons to not install - CW Often 1983-1995 dated properties will not have had any cavity wall insulation, due to the specifications of the time being more concerned with the thermal comfort of the property:
•
e.g. the builder wouldn’t install cavity insulation, but to comply with thermal comfort regs would install an up-rated heating system;
However, the software will assume there is insulation and not recommend it. You would need to inform the customer that the EPC would not make the recommendation and that they would need to seek specialist advice to ascertain whether or not CWI is present.
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Solid Wall Insulation - Advice
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External Wall Insulation To insulate a solid wall from the outside, a layer of insulation material is fixed to the walls with mechanical fixings and adhesive, then covered with protective layers of render or cladding.
The finish can be smooth, textured or painted, tiled, panelled, pebbledashed (for easy maintenance) or finished with brick slips to provide a real masonry brick finish. The finish will cover the whole of the outside of the property, including existing brickwork, and may change its appearance. Therefore, planning permission may be required.
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External Wall Insulation
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External Wall Insulation Insulating the outside of a property will: • • • •
Provide a new weather-proof layer Protect the property from penetrating damp Increase the temperature of the internal surface of the wall Reduce condensation problems on internal walls
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External wall insulation External wall insulation is most cost effective when re-rendering, or other measures to prevent rainwater penetration, are required. Any other repairs needed to the walls should be carried out first. There are two common methods: • Wet render systems • Dry-cladding
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External Wall Insulation: Dry-Cladding Cladding comes in a variety of attractive colours and forms: timber panels or shingles, stone or clay tiles, aluminium panels or a brick finish. In these systems insulation is also fixed directly to the existing wall but instead of render, a range of alternative ‘dry’ cladding materials can be used, e.g. • • • •
Timber Ceramic or clay tiles Brick slips Metal panels
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Dry-cladding
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External Wall Insulation: Wet Render Render can be either a thick sand and cement mix applied over a wire mesh, or a thinner, lighter cement over a strong fibre mesh. It is generally less expensive than cladding. In these systems, insulation batts or boards are fixed to the existing external wall, covered by a wire mesh and then an outer coating of sand/cement render to provide a waterproof finish.
Rendering
Most commonly the render is painted, but a ‘pebbledash’ finish can be used to reduce maintenance costs and/or improve the appearance.
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Eternal Wall Insulation All external pipework and other fittings will have to be removed and replaced, and it may be necessary to extend electric boxes, window sills and even the roof overhang(soffit) to protrude beyond the new layer. It is often possible to fit additional sills to avoid replacing any of the original structure. To prevent condensation, recessed areas around windows must be insulated as well as the walls – with the depth of insulation depending on the width of the window frame.
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External Wall Insulation Benefits • Can be applied without disruption to the household inside. • Does not reduce the floor area of the home. • Renews the appearance of outer walls. • Improves weatherproofing and sound resistance. • Fills cracks and gaps in the brickwork, which will reduce draughts. • Increases the life of walls by protecting the brickwork. • Reduces condensation on internal walls and can help prevent damp (but will not solve rising or penetration damp).
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External Wall Insulation Restrictions • Is not recommended if the outer walls are structurally unsound and cannot be repaired. • Best installed at the same time as external refurbishment work to reduce the cost. • May need planning permission. • Requires good access to the outer walls. • Lots of older houses have an attractive frontage which wouldn't be suitable for external insulation, but a much less impressive rear where external insulation could be just the thing. The front wall can then be insulated internally, one room at a time. Domestic GDA Training – 6. Building Fabric
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Internal Wall Insulation Internal wall insulation is sometimes referred to as ‘dry-lining’, but technically dry-lining might only consist of plasterboard with an airspace behind it, i.e. not necessarily including any insulation material.
There are two ways to insulate a solid wall internally: • Rigid insulation boards
or • Insulated stud wall
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Internal Wall Insulation
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Internal wall insulation Rigid insulation boards Plasterboard backed with rigid insulation is fitted to the inside of your walls. The insulation is usually made from one of several forms of foamed plastic. It should normally be at least 60mm thick, and can be up to 100mmm. The actual thickness required will depend on the material used. Insulation boards are fixed straight onto the wall using continuous ribbons of plaster or adhesive. Extra fixings hold the boards firm, and joints between boards are sealed to prevent air leaking out.
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Internal wall insulation Stud wall A metal or wooden studwork frame is attached to the wall and filled in with mineral wool fibre. It can then be plastered over, ready for redecoration. Mineral wool insulation is less effective than rigid insulation boards, so the filling needs to be at least 120mm thick. Instead of applying plaster, the frame can be covered with rigid insulation boards for even more effective insulation, reducing your running costs even further.
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Internal Wall Insulation
A Dot and dab (no insulation)
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B Stud wall (Insulation in between studs)
C Ridged Board (insulation backed board) Training Material © Stroma Certification 2013 | Version 1.1
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Internal Wall Insulation Disruption for internal insulation External walls will need to be removed and reattached, so that they are flush with your new ‘wall’. So will features such as: • Light fittings • Radiators • Pipe work • Skirting boards • Door frames • Coving • Cornices Areas around windows must be insulated at the same time as the walls, to prevent condensation. It is therefore also easier if the property is unoccupied, although one room could be done at a time. Domestic GDA Training – 6. Building Fabric
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Internal Wall Insulation Benefits • • • • • •
is generally cheaper to install than external wall insulation will slightly reduce the floor area of any rooms in which it is applied (the thickness of the insulation is around 100mm) is disruptive, but can be done room by room requires skirting boards, door frames and external fittings to be removed and reattached can make it hard to fix heavy items to inside walls – although special fixings are available needs any problems with penetrating or rising damp to be fixed first.
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Internal Wall Insulation Flexible thermal linings These are typically 10mm thick and applied like wallpaper
They are not thick enough to meet the standards of Part L1B but they can be useful to: •
reduce the effect of thermal bridges, e.g. on window reveals
•
in cold corners where condensation occurs
•
where space is limited, e.g. around dormers
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Hybrid insulation Hybrid systems are combination of both external and internal wall insulation installed on the same property. Care must be taken during installation to reduce cold bridging an overlap of the two insulation methods (internal & external) must be achieved to minimise the effect so condensation patches are not created.
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Damp and Condensation Insulating walls internally will make the inside surface of the wall warmer, making it less likely that moisture in the air will condense on the wall.
If a property currently has condensation problems then internal wall insulation could help reduce the problem. It is difficult to insulate every square centimetre of the house, and there are almost bound to be some areas that remain cold - for example, where an internal wall meets an external wall. There is then a risk of condensation collecting in these areas and perhaps going unnoticed until a problem develops. This problem can generally be minimised by insulating carefully around window recesses, doors and the edges of internal walls.
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Damp and Condensation If insulation is incorrectly fitted, there is also a risk that moisture will migrate from the warm air in the room through the insulation until it meets the cold solid wall (interstitial condensation).. It can then condense inside the wall structure and cause problems. This issue can be avoided by adding a vapour control layer on the inner surface of the insulation and ensuring that any breaks in this layer are carefully sealed. And as with all wall insulation, it is important to make sure that any existing problems of rising damp or penetrating damp are fixed before insulating, otherwise there is a risk of the problem getting worse over time as the moisture gets trapped within the structure. For all these reasons, internal wall insulation must be fitted by an experienced professional who can ensure that any existing damp issues are resolved and no new ones are created.
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Regulations If you insulate a solid wall, you have to make sure it complies with the current Building Regulations. •
insulated wall - if you live in England or Wales then it must have a U-value of no more than 0.30 W/m2K.
as a rough guide you will need around 60mm to 120mm of insulation to achieve this, depending on what insulation material you use.
If you are planning to remove and replace more than half of the internal plaster or external render of a wall, or if you are dry lining a wall, then you must insulate to this standard whether you were planning to insulate or not. This is a consequential improvement. Domestic GDA Training – 6. Building Fabric
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Costs Type of insulation
Saving per Year
Cost
Co2 per year
Internal
£445
£5500 - £8500
1.8 tonnes
External
£475
£9400 - -£13000
1.9 tonnes
Values based on a 3 bedroom house
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Keeping the Costs Down Internal insulation can be installed at the same time as other works – for example when a new kitchen or bathroom is fitted, or when rooms are redecorated.
External insulation can also be combined with other works. For example if scaffolding is already erected – perhaps as a new roof is being fitted, or windows are being redecorated, or solar PV panels are being fitted – then choosing to fit the insulation then could save a bit on the costs. And if rendered walls have damaged render, or brick walls need re-pointing, external insulation may not cost much more than the cost of basic repairs. Lots of older houses have an attractive frontage which wouldn't be suitable for external insulation, but a much less impressive rear where external insulation could be just the thing. The front wall can then be insulated internally, one room at a time.
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Floor Insulation - Advice
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Ground Floor Insulation Ground Floor Insulation Insulation to ground floors has been required by the Building Regulations in new homes since 1996. (This applies to England and Wales –1992 for Scotland and Northern Ireland.)
Floors to be considered: • Ground floors • Exposed floors • Floors over unheated space
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Suspended Timber Ground Floors
Sometimes there is access below a suspended timber floor, e.g. from a cellar. In these cases insulation can be installed between the joists. This is a simple process (and could be done by a DIY enthusiast).
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Ground Floor Insulation One way of doing this is to insert insulation quilt between the floor joists and hold it in place with netting stapled to the joists.
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Ground Floor Insulation Alternatively you can use rigid insulation boards and hold these against the underside of the floor boards with battens nailed to the side of the joists.
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Floor Insulation If there is no space to access a timber floor from below, insulation can only be added by taking up the floor boards. The same methods as described above can then be used. This is usually only cost effective if the floor boards need to be taken up or replaced for another reason, e.g. as part of a full refurbishment project.
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Floor Insulation The simplest way of improving the thermal performance of an existing concrete ground floor is to add insulation and a new floor deck on top of the existing floor.
Though simple, raising the floor level through added insulation will usually require: • •
Skirting's Radiators
To be removed and re-fixed and doors to be increased in height
Ensure that any remedial work is undertaken on the slab ahead of installing the insulation.
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Ground Floor Insulation An existing concrete floor can only easily be insulated by adding insulation and new flooring on top of it.
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Ground Floor Insulation Concrete ground floors If a concrete floor needs to be replaced for any reason, the new floor should be insulated. The insulation can be above or below the concrete slab –insulation below the slab has the advantage of including thermal mass.
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Ground Floor Insulation Retrofitting insulation to the ground floors of homes is rarely considered due to: •
•
Relatively low heat loss from ground floors compared to external walls or roofs, due to the insulating effect (Thermal Mass ) of the ground. The cost and practical difficulties of installing ground floor insulation in most cases.
Where insulation is specified, ensure that it does not come into contact with cabling. A fire-resistant board should be used beneath the joists if the floor is above a garage or basement.
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Draught-proofing - Advice
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Where to look for draughts Draughts happen where there are unwanted gaps in the construction of your home, and where openings are left uncovered. You’ll find draughts at any accidental gap in your home that leads outside, such as: •windows •doors – including keyholes and letterboxes •loft hatches •electrical fittings on walls and ceilings •suspended floorboards •pipework leading outside •ceiling-to-wall joints.
You should block most of these but be careful in areas that need good ventilation: •areas where there are open fires or open flues •rooms where a lot of moisture is produced, such as the kitchens, bathrooms and utility rooms. Domestic GDA Training – 6. Building Fabric
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Draught-proofing Draught proofing is a cheap and efficient method of saving both energy and money. Draughts are similar to ventilation in that they supply the home with fresh air. However, draughts are uncontrolled and can let in too much cold air as well as allowing heat to escape. Draught proofing blocks up any unwanted gaps that let cold air in. Types of draught proofing can include: • Self-adhesive sealant strips • Brushes • Spray foams (sprayed into gaps around windows) • Sealants • Weather strips (door and window reveals) Domestic GDA Training – 6. Building Fabric
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Examples of Draught proofing Examples of draught proofing include that can be financed through Green Deal. • Windows • Doors • Loft hatch insulation (loft insulation) Examples of draught proofing include that also can be financed through Green Deal. • • • •
Brushes Sealants Adhesive sealant strips Spray foams
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Draught proofing How much could you save by draught-proofing? Full draught-proofing will save you on average £55 per year. Draughtfree homes are comfortable at lower temperatures – so you’ll be able to turn down your thermostat. This could save you even more
Generally draught proofing is a measure that can be considered for most Dwellings Part F (Ventilation) Approved Document F of Schedule 1 of the Building Regulations covers the requirements in respect of ventilation. The Domestic Ventilation Compliance Guide contains the principal guidance for air bricks for open flued appliances, trickle vents, etc…
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Energy-Efficient Glazing and Doors - advice
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Energy-Efficient Glazing All properties lose heat through their windows, but energy-efficient glazing reduces this. That might mean double or triple glazing, or secondary glazing.
Energy-efficient windows come in a range of frame materials and styles. They also vary, depending on: • • •
How well they stop heat from passing through the window. How much sunlight travels through the glass. How little air can leak in or out around the window.
If a property does not have 100% energy-efficient windows, think about upgrading.
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Energy-Efficient Glazing Advice Glass: The most energy-efficient glass for double glazing is low emissivity (Low-E) glass. This often has an unnoticeable coating of metal oxide, normally on one of the internal panes next to the gap. This lets in light and heat but cuts the amount of heat that can get out. In between: Very efficient windows might use gases such as argon, xenon or krypton in the gap between the sheets of glass. Pane spacers: These are set around the inside edges to keep the two panes of glass apart. For maximum efficiency, look for pane spacers containing little or no metal – often known as ‘warm edge’ spacers Measure
Savings
Cost
C02 per annum
Double Glazing
£180
3000 - 6500
680kg
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Energy-Efficient Glazing: Benefits • Smaller energy bills: replacing all single-glazed windows with Brated double glazing could save around £170 per year. • Reduced emissions: by using less fuel, a property will generate less of the carbon dioxide that leads to global warming - typically, 680kg a year. • A more comfortable home: energy-efficient glazing reduces heat loss through windows and means fewer draughts and cold spots. • Peace and quiet: as well as keeping the heat in, energy efficientwindows insulate the property against outside noise. • Reduced condensation: energy-efficient glazing reduces condensation build-up on the inside of windows. The costs and savings for energy-efficient glazing will be different for each home and each window, depending on the size, material and installer. Double glazing should last for 20 years or more.
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Energy-Efficient Glazing Secondary glazing A secondary pane of glass and frame can be fitted inside the existing window reveal. This won’t be as well sealed as a double-glazing unit, but will be much cheaper to fit, and will still save energy you could save about £100 a year on fuel bills. Low emissivity glass will improve the performance of secondary glazing. Secondary glazing cuts down on costs and is a non-intrusive way of insulating your windows. It should be considered in Conservation Areas or on listed buildings when there are regulations in place restricting the change of a building’s appearance.
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It is the best of what can be achieved under the current regulations
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Insulated Doors Under the legislation, all new doors sold and fitted in England and Wales must have a U-value of 1.8W/m2K (1.6W/m2K in Scotland) or less. The door’s U-value is a measure of its energy efficiency, and the lower the U-value, the more energy efficient the door. Features like: • Keyhole cover • Letterbox brush • Weather and draft excluder strips • A frame fit door • Professionally fitted Will all increase the door’s energy efficiency. Doors can now be tested like windows for there energy efficiency and a simple A-G rating can be applied to individual products. All Green Deal products, including insulating doors, will have to be tested and must pass minimum standards to be used by approved Green Deal installers.
Installing insulated doors could save you £30 a year
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Conservatory's Even the best-quality glazing loses heat more quickly than an insulated cavity wall. This means that conservatories are not thermally efficient. Provided they are never heated, and the doors between the conservatory and the heated house are kept shut in cold weather, they can actually reduce heat loss by acting as an extra insulating layer on the outside your house. You can make the most of this by installing a sealed sliding door, If you heat your conservatory, any benefit you may have had will soon disappear along with the heat that escapes into the outside air in winter. Double glazing, blinds and shutters can all reduce the amount of heat wasted, but it is not possible to bring a conservatory up to the thermal standard of even an averagely insulated room. If you want to save energy and money, save your conservatory for the summer.
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Questions?
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Web Links www.stroma.com/certification
Contacts Stroma Certification Ltd. 4 Pioneer Way, Castleford, WF10 5QU 0845 621 11 11
[email protected]
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