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Approved / Accredited Construction Details are a set of standardised construction details developed by regulators to deal with the issue of heat loss / gain and other issues.

Acoustic insulation
A product used to impede the transfer of sound, either via airborne or impact transfer. Typically internal constructions within buildings are required to utilise acoustic insulation products to aid in minimising the transfer of sound from one adjacent room into another. “Approved Document E” and “Part E – Robust Details” contain further information on common methods of controlling the transfer of sound in buildings.

Air tightness
The uncontrolled leakage of air from a building through cracks, unsealed penetrations or interfaces between different building elements.

When referring to heat, temperature, etc. ambient describes the surrounding conditions. i.e. the Ambient temperature is the average temperature surrounding a material.

A ballast layer is typically used in warm or inverted roofs down to weigh down the insulation or waterproofing system. Common items used to form ballast layers include concrete paving slabs, round washed pebbles or a green roof system (e.g. plants and growing medium such as soil). The weight of the ballast required is dependent on results from a wind uplift calculation.

Building Emission Rate details the energy performance of a building calculated following the NCM (National Calculation Methodology) eg SBEM. These measurements will be compared to the TER to define whether a building passes building regulations.

Building Information Modelling is a way of managing all the information required for a construction project. This database is referred to as AIM (Asset Information Model). In accordance with the government’s ‘Construction Industry Strategy 2011’, all new public constructions should use Level 2 BIM from April 2016.

Blowing Agent
A substance used during the manufacture of cellular foam insulation products. These agents are typically used to enhance the thermal performance of the finished product by filling the cells within the insulation with a low thermal conductivity gas. The Kooltherm and Therma ranges of insulation products we produce use Pentane based blowing agents with zero Ozone Depletion Potential and low Global Warming Potential (GWP).

Best Practice Environmental Option includes initiatives such as Kingspan’s Waste Collection Service.

An environmental assessment and rating system for buildings. It uses recognised measures of performance, which are set against established benchmarks, to evaluate a building’s specification, design, construction and use.

A non–scientific term used when discussing moisture transport through a construction.

Building Control Bodies
Public and private organisations that assess and verify compliance with building regulations and standards. Building envelope separates the internal and external environments, such as a roof or walls. In order to provide the adequate protection against heat leakage, the building envelope should have as few thermal bridges and unintended gaps a possible.

Built-up roof
A roof made up of layers of building elements, typically roofing felt and asphalt with waterproofing layer and gravel on top.

Butt joints
A joint made from two materials placed end to end without overlapping. They are used in pipe insulation and when laying loose boards on a floor or roof.

Carrier membrane
This is a membrane typically used to provide a suitable substrate for laying another product, i.e. such as for a liquid applied waterproofing system to be applied onto. Refer to individual waterproofing manufacturers for specific recommendations on when such layers are required, and if they are what is used for them.

Cavity closers
Insulated extrusions for closing wall cavities at openings such as window reveals and door reveals. Cavity closers reduce heat transfer, avoiding thermal bridging, condensation and mould growth. They can even be used to pre–form openings when window and door frames are fitted later. Kingspan Kooltherm Cavity Closer and Kingspan Thermabate are examples.

CE Label
This shows compliance with EN and CEN standards.

Cellular insulation
Insulation such as polyurethane, polyisocyanurate and phenolic insulation, which is made up of small individual cells.

Centres of rafters / joists
The centres of joists or rafters are measured by taking the centre point of one joist/rafter to the centre point of the following adjacent joist/rafter. Timber joists and rafters are traditionally located at 400 mm, 450 mm or 600 mm centres, or in refurbishments sometimes their imperial approximate equivalents of 16, 18 and 24 inches.

Closed cell insulation
This has a more compact and denser structure than open cell insulation. As a result, it decreases the ingress of moisture and is more resistant to heat transmission. Insulation with a closed cell structure is also more resistant to flood damage. Because of its low water take–up, closed cell insulation panels recover from immersion in flood water more quickly than mineral fibre insulations for example.

Cold bridging
A type of thermal bridging that occurs when a structural element of a building lets heat flow through it because it has a lower thermal resistance than other components in the construction.

Compressive creep
The measure of how much a material changes under long–term load. Heavy duty insulation materials ideally have a low compressive creep so they have a suitable durability in heavy duty applications.

Compressive trength
A material’s ability to maintain its structural integrity when compressed. Insulation products with a high compressive strength such as Kingspan Styrozone are used for heavy duty floors and roofs.

The conversion of a substance (typically water when referenced in the construction industry) from the vapour state to a liquid due to a change in temperature or pressure, e.g. such as warm moist air hitting a cold surface causing: a reduction in temperature of the air; and moisture vapour to condense out of the air. The two main occurrences of condensation are:

  • Surface condensation which can lead to mould and staining through its formation on the visible surface of a material.
  • Interstitial condensation occurs between the layers of a construction. This type of condensation can both reduce the effectiveness of insulation components and reduce their lifespan.

Condensation Risk Analysis is performed on the construction elements of a building, taking into account the order in which they appear, and the building’s geographical location. Our technical department present CRA with U–value calculations.

Dwelling Emission Rate details the energy performance of a building calculated using SAP. These measurements will be compared to the TER to define whether a dwelling passes building regulations.

Dwelling Fabric Energy Efficiency. This is compared to the TFEE to comply with building regulations in England.

A damp proof membrane is used with some insulations to prevent moisture building up on the insulation layer.

The ‘shininess’ of a material. A high emissivity will increase the amount of heat transfer through radiation. It is measured in watts per square metre (W/m2) in relation to an ideal black surface as a ratio from 0 to 1. The closer to 0 the emissivity ratio, the lower the emission of heat as radiation. A foil facing on an insulation board allows a low emissivity to be taken when calculating the thermal resistance of an unventilated airspace eg. in a cavity wall construction.

An Energy Performance Certificate is required upon completion of a dwelling in accordance with the English, Scottish and Welsh building standards. This necessitates energy calculations eg. SAP or SBEM. They measure on a scale of A–G, the green to red scale covers the energy efficiency rating, while the blue to grey scale measures the environmental impact rating of the construction.

Expanded polystyrene is a light rigid foam insulation that has low thermal conductivity and high impact resistance.

External wall insulation – insulation installed on the outside or cold side of a wall.

The surface element of an insulation board. Rigid and semi–rigid insulation boards often have a foil facing which lowers the emissivity of the insulation element.

Fibrous insulation
An insulation material made up of fibres rather than cells.

Fully bonded
Typically used in reference to flat roofing, and refers to where a bond between two materials is considered to cover the whole surface. As a full bond covers a greater proportion of the roof area, these systems can generally provide greater restraint against wind uplift than partially bonded systems.

Geotextile membrane
A non–woven geo–synthetic membrane used in a variety of applications within the construction industry to act as separation and filtration membranes.

Global Warming Potential is a relative measure of how much heat a greenhouse gas traps in the atmosphere, and in turn how much the product is estimated to contribute towards global warming. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide. A GWP is calculated over a specific time interval, commonly 20, 100 or 500 years.

Green Guide Rating
The 2008 Green Guide Rating system uses data from Environmental Profiles to classify performance of construction materials in a number of areas to award a summary rating on a scale of E (worst) up to A+ (best).

HTB or Transmission heat transfer coefficient associated with non–repeating thermal bridges
The HTB is the overall sum of heat–loss / gain from each junction multiplied by that junction’s length.

International Standardisation Organisation is a certification body that provides assessments such as 9001- quality management, 14001- environmental management, 18001- Occupational Health and Safety (OHSAS), and 50001- energy management.

Internal wall insulation, insulation on the inside or warm side of a wall.

Kappa value
This relates to the thermal mass of a construction. It is the measure of how much heat will be stored per metre squared of a building and represents ‘k’ in the unit of measure kJ/m²K. ‘k’, or the heat capacity of a building, can be calculated using the following equation:

k = 10 – 6 x Ʃ (dj rj cj)

dj = thickness of layer (mm)

rj = density of layer (kg/m³)

cj = specific heat capacity of layer (J/kg·K)

The calculation is over all layers in the element, starting at the inside surface and stopping at whichever of the following conditions is encountered first (which may mean part way through a layer):

  • The total thickness of the layers exceeds 100 mm
  • The midpoint of the construction is reached
  • An insulation layer is reached (defined as thermal conductivity ≤ 0.08 W/m·K)

Lambda value
Sometimes called the ‘k–value’ or ‘ʎ–value’, this measures the thermal conductivity of a material. k–value is shown in units of W/m·K where ‘m’ represents the thickness of the material in metres. Insulants have a low thermal conductivity meaning heat cannot pass through them easily. The k–value shows the general performance of a material with regards to thermal conductivity and does not relate to the material’s thickness.

Life Cycle Assessment is how the environmental impact of a building is assessed from raw materials to disposal or recycling.

Loose fill insulation
For example, cellulose or mineral insulations that are typically installed in the air cavities of buildings through a gap or drilled hole in the building element.

Moisture ingress
The act of water entering something. In construction terminology the term is typically used in reference to external moisture (i.e. ground moisture or precipitation) entering a construction.

Mechanical Ventilation with Heat Recovery: A system that ventilates a space by removing indoor air, recovering the heat from that indoor air, and using it to pre–heat fresh air from outside.

Open cell insulation
This insulation has a structure that allows moisture and vapour to permeate through it.

Oriented Strand Board, also known as OSB, sterling board or exterior board, is an engineered wood product formed by layering strands (flakes) of wood in specific orientations set within a resin to form a rigid board. The product is typically available in differing thickness from 6–25 mm, and comes in differing grades from 1–4. Grades 2–4 are most common, with grade 3 or 4 generally being used in structural applications. A common application for boards of this type is as a structural sheathing to timber frames where they enhance the bending and racking strength of the frame.

P/A ratio
The perimeter / area ratio is worked out by dividing the exposed perimeter given by the floor area. This will calculate how much floor insulation is need. The exposed perimeter refers only to the walls that connect to an unheated space, so this will mainly be an outside space or areas such as a garage. The smaller the P/A figure the smaller the amount of insulation that is required, for example, a large area with a small exposed perimeter will have less heat loss and, therefore, will require less insulation.

Partial bonding
Typically used in reference to flat roofing and relates to the method of bonding various components to the substrates beneath. When using a partial bond only a proportion of the two adjacent layers are bonded to one another, this can be to allow for a degree of differential movement, the release of gas during installation, or just due to discontinuity in the substrate, i.e. such as in the case of a profiled metal deck. When referring to built–up bituminous felt partially bonded systems are generally achieved by using a 3G perforated felt, which is loose laid above the substrate (i.e. deck or insulation) and the next layer of felt is then partially bonded to the substrate at the points of the perforations in the 3G layer.

Passivhaus or Passive House Standard
‘A Passivhaus is a building, for which thermal comfort can be achieved solely by post–heating or post–cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.’ The Passivhaus standard is a very high standard of energy efficiency by reducing levels of heat loss through high levels of insulation and preventing air loss, the building is heated passively through the sun, human occupants and household appliances with the remaining heat being supplied through heating or cooling of air in a mechanical ventilation system.

Phenolic Foam (PF)
An insulant such as Kingspan Kooltherm rigid phenolic boards. It has a high compressive strength and a closed cell structure. The thermal conductivity of phenolic foam is lower than that of rigid polyurethane or extruded polystyrene.

In ductwork, a plenum is a space above a ceiling that allows the collection of air in order to let it move between different spaces in the building.

Polyisocyanurate foam is a rigid polymeric foam insulation, for example Kingspan Thermapitch that has a thermal conductivity of 0.022 W/m·K.

Psi value or Ψ value
The measure of heat loss per K shown in units of W/m·K where ‘m’ details the length of a junction in metres. It is used to estimate the potential for non–repeating thermal bridges.

A family of rigid cellular thermoset polymeric foam with a close cell structure that forms both PIR and PUR based polymer forms. Kingspan’s Therma range is made up of PU rigid urethane insulants.

Polyurethane foam is a rigid polymeric foam insulation with a high thermal resistance and low thermal conductivity. It can be used on its own or to seal air gaps between existing insulation elements.

The installation of insulation over pre–existing building elements or insulation.

Relative Humidity is a percentage that measures the relationship between the actual moisture content of the air and the saturated moisture content of the air.

This demonstrates thermal resistance of a material in relation to its thickness. It is measured in units of m²·K/W where ‘m’ represents the thickness of the material in metres which is divided by its value.

Standard Assessment Procedure which measures the energy performance or efficiency of a domestic building. It covers the energy consumed in relation to the floor area, a fuel–cost–based efficiency rating, and CO2 emissions. The procedure follows the structure of BREDEM (BRE Domestic Energy Model).

Sarking board
Rigid boards, such as timber planks, plywood or OSB used above rafters in a pitched roof. The use of sarking boards is most common in Scotland, where traditionally sarking boards comprised softwood sawn planks fixed to the upper face of the rafters.

Simplified Building Energy Model assesses the energy efficiency of a non–domestic building. The software is used to measure the CO2 emissions of non–domestic buildings and whether they comply with building regulations and standards.

Structurally Insulated Panels are a combination of insulation and structural elements such as timber facings in one board. An example is the Kingspan TEK Building System.

The underside of an architectural component, for example an arch, beam, staircase or underneath car park decks. Insulations for this type of building element include Kingspan Kooltherm K110 Soffit Board and Kooltherm K110 PLUS Soffit Board.

Tanking membrane
A waterproof membrane used to prevent moisture ingress further into a construction. Products of this type are often used in basement wall or floor constructions. A variety of materials ranging from membranes to liquid applied systems, with both bituminous, cementitous and synthetic plastic products all being available in the market place.

Target Emission Rate, which is based on a ‘notional building’, concurrent specification, which differs based on the country in which you are building (eg England, Wales or Scotland).

Target Fabric Energy Efficiency is an additional standard in England presented alongside the TER. Thermal bridges are channels through which heat can be lost when a material has a higher thermal conductivity than adjacent building elements. They can also be referred to as cold bridges or heat bridges. The three main types of thermal bridges are:

  • Repeating thermal bridges which develop in a regular pattern, for example where there are timber studs in walls. U–value calculations take account of the effect of repeating thermal bridges e.g. a 15% timber bridging fraction might be taken for studs in a timber framed wall.
  • Non–repeating / linear thermal bridges occur in an irregular pattern at junctions between building elements eg around windows or between walls and floors.
  • Point thermal bridges are used as adjustments to the U–value of a building element. They take account of thermal bridging at fixings, fasteners and beams.

Thermal conductivity
The measure of thermal conductivity used on materials in which heat transfer occurs through conduction, convection and radiation.

Thermal mass
This is how well an element absorbs, stores and releases heat per metre squared (see Kappa value).

Thermal resistivity
As with thermal conductivity, this measures a material’s ability to resist heat transfer through conduction, convection and radiation in relation to the material’s thickness or surface emittance (see emissivity).

A type of insulation that sets permanently after cooling. If the insulation is reheated it will not change shape. Thermoset materials will not run, melt or drip when exposed to fire. Examples include Kingspan’s Kooltherm and Therma ranges.

The sum of the thermal resistances of the layers that make up a building element (i.e. walls, floors, roofs etc.). It includes adjustments for any fixings, air gaps etc. This value shows in units of W/m²·K the ability of an element to transmit heat from a warm space to a cold space in a building and vice versa. The lower the U–value, the better insulated the building element is. Our U-Value Calculator is a helpful tool for calculating U-values.

The process of “changing” or replacing air in any space to remove excess moisture or other pollutants, such as carbon dioxide or ground gases such as radon and replaced with external air (see MVHR).

Water flow reduction layer
A membrane such as Kingspan Aquazone typically utilised within inverted roof constructions where it is laid above the thermal insulation to aid in minimising the cooling effect associated with rain water draining beneath thermal insulation. These products typically compose non–woven, spun–bonded polyolefin with micro–perforations which allow the escape of moisture vapour while preventing the majority of liquid water from peculating further down into the construction.

Wind uplift / wind load calculations
Wind can apply a positive or negative force onto objects depending on the construction detail, its orientation to the direction of wind, and the difference between internal and external air pressures. Wind load calculations are particularly important for systems restrained to the outside of a building, such as warm or inverted flat roofs and external wall insulation systems such as EWI render and rainscreen systems. A wind load calculation considers a number of factors, such as the location and altitude of the building plot, local topography (i.e. geographical features, valleys, hillside etc.), adjacent structures which may shelter or funnel wind towards the building, also the construction type, its height from ground, and position on the construction in relation to the prevailing wind direction.

Extruded polystyrene has high resistance to condensation damage and has a high thermal resistance. Kingspan Styrozone is a rigid extruded polystyrene.

An approximation of a specific building’s heat loss via its junctions. It is calculated by dividing the HTB (overall thermal bridging coefficient) by the building’s total exposed area (see HTB).

Quick guides

These guides covers it all. From how insulation is made to building regulations for common projects at work and home. They should answer most of the questions you have about our insulation... If they don't then get in touch.

Everything you ever wanted to know about insulation

Kooltherm Quick Guide

Therma Quick Guide

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