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KORE LOCK INSULATION TECHNICAL DETAILS

KORE Lock is an expanded polystyrene (EPS) insulation system for use in warm and cold pitched roofs. Download the KORE Lock Insulation Design Guide for detailed technical information, or join the KORE Resource Centre for access to our full technical library.

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KEY FEATURES & BENEFITS

  • Meets and exceeds Building Regulations
  • Provides excellent thermal properties
  • Simple and safe to install
  • Allows for variable width adjustment
  • Easily facilitates necessary ventilation requirements
  • Can be used for cold and warm pitched roofs

U-VALUE CALCULATIONS

All U-value calculations are in accordance with BS EN ISO 6946:2007. The calculations take account of fixings for both the warm roof and cold roof applications. The roof finish for all calculations were taken as clay roof tiles. The timber centres were taken as 400mm. Please contact our technical team for calculations at different centres. It is assumed that the insulation is fitted accordingly and the correction factor for air gaps has been ignored. All calculations take account all of the necessary ventilation. Warmsark board is tongue and grooved.

Detail 1: Warm Pitched Roof - Insulation Between and Over Rafters (With Sarking Board)

U-Value Calculations: KORE Lock EPS70 Silver (0.031W/mK) & KORE Warmsark EPS100 Silver (0.031W/mK) 

KORE Lock EPS70 Silver KORE Warmsark EPS100 Silver U-Value (W/m2K)
100mm 50mmKOR 0.22
125mm 50mm 0.19
150mm 50mm 0.17
175mm 50mm 0.15
200mm 50mm 0.14

U-Value Calculations: KORE Lock EPS70 Silver (0.031W/mK) & KORE Warmsark EPS100 Silver (0.031W/mK)

KORE Lock EPS70 Silver KORE Warmsark EPS100 Silver U-Value (W/m2K)
100mm 100mm 0.16
125mm 100mm 0.14
150mm 100mm 0.13
175mm 100mm 0.12
200mm 100mm 0.11

U-Value Calculations: KORE Lock EPS70 White (0.037W/mK) & KORE Warmsark EPS100 White (0.036W/mK)

KORE Lock EPS70 White KORE Warmsark EPS100 White U-Value (W/m2K)
100mm 50mm 0.25
125mm 50mm 0.22
150mm 50mm 0.19
175mm 50mm 0.17
200mm 50mm 0.16

U-Value Calculations: KORE Lock EPS70 White (0.037W/mK) & KORE Warmsark EPS100 White (0.036W/mK)

KORE Lock EPS70 White KORE Warmsark EPS100 White U-Value (W/m2K)
100mm 100mm 0.18
125mm 100mm 0.17
150mm 100mm 0.15
175mm 100mm 0.14
200mm 100mm 0.13

Detail 2: Cold Pitched Roof - Insulation Between and Under Rafters (No Sarking Board)

U-Value Calculations: KORE Lock EPS70 Silver (0.031W/mK) & KORE Thermal Board EPS70 Silver (0.031W/mK)

KORE Lock EPS70 Silver KORE Thermal Board EPS70 Silver U-Value (W/m2K)
100mm 50mm 0.21
125mm 50mm 0.19
150mm 50mm 0.17
175mm 50mm 0.15
200mm 50mm 0.14

U-Value Calculations: KORE Lock EPS70 Silver (0.031W/mK) & KORE Thermal Board EPS70 Silver (0.031W/mK)

KORE Lock EPS70 Silver KORE Thermal Board EPS70 Silver U-Value (W/m2K)
100mm 100mm 0.16
125mm 100mm 0.15
150mm 100mm 0.13
175mm 100mm 0.12
200mm 100mm 0.11

U-Value Calculations: KORE Lock EPS70 White (0.037W/mK) & KORE Thermal Board EPS70 White (0.037W/mK)

KORE Lock EPS70 White KORE Thermal Board EPS70 White U-Value (W/m2K)
100mm 50mm 0.25
125mm 50mm 0.22
150mm 50mm 0.20
175mm 50mm 0.18
200mm 50mm 0.16

U-Value Calculations: KORE Lock EPS70 White (0.037W/mK) & KORE Thermal Board EPS70 White (0.037W/mK)

KORE Lock EPS70 White KORE Thermal Board EPS70 White U-Value (W/m2K)
100mm 100mm 0.19
125mm 100mm 0.17
150mm 100mm 0.16
175mm 100mm 0.14
200mm 100mm 0.13

Thermal Bridging

TGD Part L of the Irish Building Regulations states that care must be taken to ensure the continuity of insulation and to limit local thermal bridging and that any thermal bridge should not pose a risk to surface or interstitial condensation. KORE have undertaken a thermal bridging analysis of KORE Lock Insulation at this typical junction. Contact our team today to request a copy of these results. To minimise cold bridging at pitched roofs, continuity of insulation between the wall and attic junction is critical.

PITCHED ROOF INSULATION TECHNICAL DETAILS

Building Standards

KORE Lock Insulation can easily satisfy the requirements of the Irish Building Regulations outlined in:

  • Part L - Conservation of Fuel and Energy - Dwellings (2011)
  • Part L - Conservation of Fuel and Energy - Building other than Dwellings (2008)

The following standards should be consulted regarding the construction of insulation at rafter level:

  • B.S. 5250:2002 Code of practice for control of condensation in buildings
  • BRE GBG37 Insulating roofs at rafter level: sarking insulation
  • BS 9250:2007 Code of practice for design of airtightness of ceilings in pitched roofs
  • BRE BR262 Thermal insulation: avoiding risks 2nd edition
  • IS ICP 2:2002 Code of practice for slating and tiling

For retrofit installations consult:

  • NSAI S.R. 54:2014 Code of practice for the energy efficient retrofit of dwellings

Ventilation Construction 

With rafter insulation applications the designer will either choose a ventilated or an unventilated construction type. Unventilated design options are only suitable in retrofit situations where the structure is being re-roofed, as this level of retrofit will allow for a breathable sarking membrane to be installed. The majority of retrofit situations will not be suitable for unventilated design.

The position of the insulation will determine the make up of the roof structure. In warm unventilated pitched roofs the insulation is placed between the rafters and over the rafters. This approach is favourable where very high thermal performance is required as the depth of insulation will not impact on head heights internally. Warm pitched roofs do not require cross ventilation because the insulation placed over the rafters reduces the thermal bridging effect and the structure of the roof is maintained at an environment close to that of an internal occupied space and thus reducing the risk from condensation. Where the rafters are not fully filled with insulation a service cavity between the insulation and the plasterboard can be maintained.

In cold unventilated pitched roofs the insulation is placed between the rafters and under the rafters. As per building regulations, a 50mm ventilated air gap between the insulation and sarking felt must be maintained in order to avoid condensation. In some instances breathable sarking membrane may allow the recommended air gap to be reduced. In these instances the recommendations of the sarking membrane manufacturer must be followed.

Sarking Membranes

It is recommended that pitched roofs with slates or tiles should incorporate an underlay to direct any penetrating or condensed water to the roof drainage system. The underlay will reduce the potential for wind uplift of unsecured slate and tile and also prevent wind driven rain, air particles and snow from entering the roof space. The underlay can be either fully supported on the KORE Board (fitted in horizontal runs), the sarking board (fitted in vertical runs) or draped over the counter battens (fitted in vertical runs). The joints of the underlay must be sealed in accordance with the manufacturers instructions. Holes and tears in the underlay should be made good before applying the external roof covering.

Vapour Control Layer

A vapour control layer directly behind the internal finish can reduce the transfer of moisture into the insulated roof structure. It is important to note that vapour control layers are not a substitute for ventilation. A vapour control layer with the KORE Lock system can be provided by a vapour check plasterboard or by the application of two coats of Gyproc Drywall Sealer. Alternatively, a layer of polythene sheeting will provide a vapour control layer. The requirement for a vapour control layer should be assessed in accordance with BS 5250:2002 Code of practice for control of condensation in buildings.

Wind Loading

Across Ireland and the United Kingdom a variety of wind-loading and uplift conditions are experienced. Calculations to determine the correct size batten and the pattern of nailing must be determined for the particular site in accordance with the relevant code of practice.

Density

KORE Lock EPS70 Silver & White: 15kg/m3
KORE Warmsark EPS100 Silver & White 20kg/m3
KORE Thermal Board EPS70 Silver & White 15kg/m3

Thermal Conductivity

The thermal conductivity of KORE Lock Insulation products are in accordance with IS EN 13163:2012 and EN 12667 Thermal performance of building materials and products - determination of thermal resistance by means of guarded hot plate and heat flow meter method:

KORE Lock EPS70 White 0.037W/mK
KORE Lock EPS70 Silver 0.031W/mK
KORE Warmsark EPS100 White 0.036W/mK
KORE Warmsark EPS100 Silver 0.031W/mK
KORE Thermal Board EPS70 White 0.037W/mK
KORE Thermal Board EPS100 White 0.031W/Mk

Thermal Resistance

  KORE Lock EPS70 White KORE Lock EPS70 Silver
Thickness Insulation (mm) Thermal Resistance (m2.K/W)
100 2.70 3.23
125 3.38 4.03
150 4.05 4.84
175 4.73 5.65
200 5.41 6.45
250 6.76 8.06
275 7.43 8.87
300 8.11 9.68

 

  KORE Warmsark EPS100 White KORE Warmsark EPS100 Silver
Thickness Insulation (mm) Thermal Resistance (m2.K/W)
40 1.11 1.29
50 1.39 1.61
60 1.67 1.94
70 1.94 2.26
80 2.22 2.58
90 2.50 2.90
100 2.78 3.23

 

  KORE Thermal Board EPS70 White KORE Thermal Board EPS70 Silver
Thickness Insulation (mm) Thermal Resistance (m2.K/W)
25 0.68 0.81
38 1.03 1.23
50 1.35 1.61
88 2.38 2.84

 

DECLARATION OF PERFORMANCE CERTIFICATES

The following Declaration of Performance Certificates can be viewed or downloaded directly by clicking on the link below. You can find all our technical documents on the KORE Resource Centre.

KORE Lock EPS70 Silver
KORE Lock EPS70 White
KORE Lock EPS100 Silver
KORE Lock EPS100 White

 

 

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