The impact of under slab insulation on building performance

Insulat ion

The impact of under slab insulation on building performanceHOW A ‘ONE-FITS-ALL’ INSULATION SOLUTION CAN HELP ACHIEVE A 6 STAR ENERGY EFFICIENCY RATING IRRESPECTIVE OF NATHERS CLIMATE ZONE OR ORIENTATION.

Issue 1 May 2017

A4/12 Carb5-1

Compacted Aggregate / Sand BlindingKingspan Kooltherm

® K3 Floorboard

Damp Proof Membrane

Subsoil

Masonry Cavity Wall

Kingspan Kooltherm®

K8 Cavity Board

Concrete Slab

Separation Layer (e.g. polythene sheet)

Low Energy – Low Carbon Buildings

www.kingspan.com/au/6star

2

Introduction

“Would the addition of Kingspan Kooltherm® K3 Floorboard under a CSOG construction provide a significant increase in overall thermal performance when compared to uninsulated slabs?”

In Victoria all new dwellings, renovations, alterations and additions need to comply with the 6 Star Standard in the National Construction Code. The 6 Star Standard applies to the thermal performance of a dwelling, renovation or addition. A 6 Star energy efficiency rating applies to a dwelling’s building envelope – its roof, walls, windows and floor. Design options that go beyond minimum regulatory requirements pay in the long run and improve the value of a dwelling.

Meeting 6 Star compliance is not difficult. It’s about good design, planning and taking advantage of benefits, such as increased comfort, savings on energy bills and making a dwelling more resilient to changes in climate. A dwelling’s orientation can add up to 1 Star to the rating.

6 Star dwellings are projected to use 24% less energy through heating and cooling, compared to 5 Star dwellings, which means a potential saving on today’s energy bill, as well as considerably more on future bills, as energy costs continue to grow. 1

Kingspan Kooltherm® K3 Floorboard under slab insulation achieves a 6 Star rating across different climate zones and most orientations, without the need to change any other building specifications, such as glazing, shading or additional insulation in walls and ceilings.

To test this, a study by Graham Energy (graham.energy) was conducted to show the impact of Kingspan Kooltherm® K3 Floorboard under slab insulation on the Star rating of a typical residential dwelling in Victoria, when compared to no insulation (concrete slab-on-ground [CSOG]) and waffle pod construction. Would the addition of Kingspan Kooltherm® K3 Floorboard under a CSOG construction provide a significant increase in overall thermal performance when compared to uninsulated slabs?

1 Victorian Building Authority – Six Star Standard (vba.vic.gov.au/consumers/6-star-standard)

Background

3

Study Methodology

A baseline FirstRate5 assessment was established for a dwelling with typical building fabric insulation levels and glazing specifications. The concrete slab floor construction was then assessed under the following three conditions:

1. without insulation2. with Kingspan Koolherm® K3 Floorboard3. with waffle pod construction

This dwelling was assessed in three different NatHERS climate zones in Victoria with differing orientation. The locations selected (Brunswick, Truganina and Cranbourne East) were all in high growth areas.

The waffle pod construction selected as a comparison was 375-85, or 375 mm high waffle pod with 85 mm structural slab. This option represents a ‘best case’ scenario with a maximum R0.9 currently permitted in all NatHERS software.

To allow for a better representation of the benefit of under slab insulation, the scope was broadened to include all cardinal and ordinal directions, as providing only the four primary cardinal directions (north, south, east, west) did not represent a complete picture based on the selected design.

The DwellingThe dwelling selected was a single level dwelling designed by Henley. It is part of the Carmelle series with the Lux Q2 options selected – 4 bedrooms; 2 bathrooms; powder room; double garage; 4 living areas, including a theatre room; kids retreat; butler’s pantry and alfresco area.

SQU

AR

ES

LOT W

IDTH 14M

+28.37

ca

rme

llelu

x Q2

42.5

24

LIVIN

G A

RE

AS

Living4700 x 4990

Dining

3430 x 4320

Theatre3830 x 5300

Kids' R

etreat3150 x 3000

BE

DR

OO

MS

Master S

uite3290 x 4850

Bed 2

3330 x 3000

Bed 3

3150 x 3200

Bed 4

3000 x 3300

OU

TDO

OR

RO

OM

Alfresco

2760 x 4690

TOTA

L AR

EA

S

Ground Floor

209.2 m2

Garage

36.5 m2

Porch

4.1 m2

Alfresco

13.5 m2

Total28.37 sq

263.6 m2

Exterior Length

25,360

Exterior W

idth12,800

MIM

IMU

M LO

T WID

TH

Metric

14 m

Imperial

46 ft

Dim

ensions and floorplan shown are based on B

roadway facade.

Copyright H

enley Arch Pty Ltd. All rights reserved. All plans are copyright, no part may be used, reproduced or copied by any m

eans or in any form w

ithoutthe prior perm

ission of Henley Arch Pty Ltd.

All measurem

ents are in millim

eters unless otherwise stated. M

arketing plans are representative only. Please refer to master draw

ings for accurate featuresand dim

ensions. Lot widths are based on standard facade and m

ay vary depending on facade chosen. Please speak to your Sales Consultant for a full list of

standard inclusions. Due to estate requirem

ents and council guidelines some lot w

idth requirements w

ill change and need to be used as a guide only.

4

Study Methodology

The specifications below are independent of those adopted by Henley and were used for testing purposes only.

Specification A, which provides the lowest thermal performance, has been tested under all three conditions

(without insulation, with Kingspan Kooltherm® K3 Floorboard and with waffle pod construction), whereas specifications B and C, which provide a gradually increasing thermal performance, have only been tested for CSOG without insulation and CSOG with waffle pod construction.

Dwelling Specification A House Garage

Insulation External Wall R2.0 wall batt None

Internal Wall None R1.5 wall batt

Ceiling R3.5 ceiling batt None

Building Sealing Roof Sarking Not sarked Not sarked

Dwelling Specification B House Garage




Building Sealing Roof Sarking Sarked Sarked

Dwelling Specification C House Garage




Building Sealing Roof Sarking Sarked Sarked

5

Climate Zones

French Island

Geelong

Werribee

Melbourne

Port Phillip Bay

BRUNSWICK

Melbourne Monthly Climate Data

Tem

pera

ture

(°C

), M

oist

ure

(g/k

g), W

ind

(m/s

ec) o

n si

te

Sola

r kW

h pe

r mon

th

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

0.0

300

250

200

150

100

50

0

Global Solar

Av. Max.

Av. Min.

Wind

Moisture

NatHERS Climate Zone 21

Suburb Brunswick

Postcode 3056

Elevation 45.76 metres above sea level

* Sourced from the online NatHERS Interactive Climate map.

6

Study Methodology

French Island

Geelong

Werribee

MelbourneTRUGANINA

Port Phillip Bay

Tullamarine Airport Monthly Climate Data

Tem

pera

ture

(°C

), M

oist

ure

(g/k

g), W

ind

(m/s

ec) o

n si

te

Sola

r kW

h pe

r mon

th Global Solar

Av. Max.

Av. Min.

Wind

Moisture


40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

0.0

300

250

200

150

100

50

0


Suburb Truganina

Postcode 3029



7

French Island

Geelong

Werribee

Melbourne

CRANBOURNE EASTPort Phillip Bay

Moorabbin Airport Monthly Climate Data

Tem

pera

ture

(°C

), M

oist

ure

(g/k

g), W

ind

(m/s

ec) o

n si

te

Global Solar

Av. Max.

Av. Min.

Wind

Moisture


40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

0.0

300

250

200

150

100

50

0

Sola

r kW

h pe

r mon

th


Suburb Cranbourne East

Postcode 3977



8

Findings

Star Rating Summary

Orientation CSOG (A)

CSOG (B)

CSOG (C)

Waffle Pod (A)

Waffle Pod (B)

Waffle Pod (C)

K3 25

K3 30

K3 40

K3 50

NatHERS CZ 21 S 5.3 5.4 5.6 5.7 5.9 5.9 5.8 5.9 5.9 6.0

Brunswick SW 5.2 5.4 5.5 5.7 5.9 5.9 5.8 5.9 5.9 5.9

W 5.3 5.4 5.6 5.8 5.9 6.0 5.9 5.9 5.9 6.0

NW 5.4 5.6 5.7 5.9 6.0 6.1 5.9 6.0 6.1 6.1

N 5.5 5.7 5.8 6.0 6.2 6.2 6.1 6.2 6.2 6.3

NE 5.4 5.5 5.7 5.8 5.9 6.1 5.9 5.9 6.0 6.1

E 5.3 5.4 5.6 5.8 5.9 5.9 5.9 5.9 5.9 6.0

SE 5.2 5.3 5.4 5.7 5.8 5.9 5.8 5.8 5.9 5.9

NatHERS CZ 60 S 5.2 5.3 5.4 5.7 5.9 5.9 5.8 5.9 5.9 6.0

Truganina SW 5.1 5.3 5.4 5.7 5.8 5.9 5.8 5.8 5.9 5.9

W 5.2 5.4 5.4 5.7 5.9 5.9 5.9 5.9 5.9 6.0

NW 5.3 5.4 5.6 5.9 6.1 6.1 5.9 6.0 6.1 6.2

N 5.4 5.6 5.8 6.1 6.2 6.3 6.2 6.2 6.3 6.3

NE 5.3 5.4 5.6 5.8 5.9 6.1 5.9 5.9 6.1 6.1

E 5.2 5.3 5.4 5.7 5.9 5.9 5.9 5.9 5.9 6.1

SE 5.1 5.3 5.4 5.6 5.8 5.9 5.8 5.8 5.9 5.9

NatHERS CZ 62 S 5.1 5.3 5.4 5.7 5.9 5.9 5.8 5.9 5.9 6.1

Cranbourne East SW 5.1 5.3 5.4 5.7 5.9 5.9 5.8 5.9 5.9 6.0

W 5.2 5.3 5.4 5.8 5.9 6.0 5.9 5.9 6.0 6.1

NW 5.3 5.4 5.6 5.9 6.0 6.1 5.9 6.0 6.1 6.2

N 5.4 5.6 5.7 5.9 6.2 6.3 6.1 6.2 6.3 6.3

NE 5.3 5.4 5.6 5.9 6.0 6.1 5.9 6.0 6.1 6.2

E 5.2 5.4 5.4 5.8 5.9 6.0 5.9 5.9 6.1 6.1

SE 5.1 5.3 5.4 5.7 5.9 5.9 5.8 5.9 5.9 6.0

9

WSWS NEN SEENW

CSOG (A) CSOG (B) CSOG (C) Waffle Pod (A) Waffle Pod (B) Waffle Pod (C) K3 25 K3 30 K3 40 K3 50

6.36.26.16.05.95.85.75.65.55.45.35.25.15.0

Orientation

Star

s

NatHERS CZ 21 (Brunswick)

WSWS NEN SEENW


6.36.26.16.05.95.85.75.65.55.45.35.25.15.0

Orientation

Star

s

NatHERS CZ 60 (Truganina)

WSWS NEN SEENW


6.36.26.16.05.95.85.75.65.55.45.35.25.15.0

Orientation

Star

s

NatHERS CZ 62 (Cranbourne East)

10

Findings

The dwelling with no under slab insulation, across all three climate zones with varying orientations, ranged between 5.1 to 5.5 Stars. This is below the minimum regulatory requirement of 6.0 Stars in Victoria and additional improvements to building specifications would need to be considered to achieve compliance.

Adopting the maximum permitted waffle pod construction with R0.9 achieved minimum regulatory compliance in two of the three climate zones, however this was only when the orientation of the dwelling was optimal for the design – due north.

The introduction of Kingspan Kooltherm® K3 Floorboard 25 mm (R1.2) ensured the dwelling achieved minimum regulatory compliance in all three climate zones but, similar to the waffle pod construction with R0.9, only when the orientation of the dwelling was ideal.

Increasing the floor insulation to Kingspan Kooltherm® K3 Floorboard 30 mm (R1.4) provided greater flexibility in achieving minimum regulatory compliance across all three climate zones, especially when the orientation of the dwelling was slightly less than optimal. For waffle pod construction to achieve similar results to that of Kingspan Kooltherm® K3 Floorboard 30 mm (R1.4), overall specifications of the dwelling would need to be improved.

Stepping up the floor insulation specification again, to Kingspan Kooltherm® K3 Floorboard 40 mm (R1.9), provided even greater scope to achieve minimum regulatory compliance of 6 Stars. This included achieving 6 Stars, or greater, for all orientations from W to E in one of the climate zones – climate zone 62 Cranbourne East.

Kingspan Kooltherm® K3 Floorboard 50 mm (R2.5) achieves minimum regulatory compliance across almost all orientations in the three NatHERS climate zones – 20 of 24 orientations across the three zones rated 6.0 Stars or above, with just 4 ratings at 5.9 Stars.

Even with significantly increased wall and ceiling insulation, as well as building sealing levels (Specifications B & C), neither the CSOG without insulation, nor the waffle pod construction, could improve up to the level of the Kingspan Kooltherm® K3 Floorboard insulation option.

ConclusionThese results show the addition of Kingspan Kooltherm® K3 Floorboard under a CSOG construction provides a significant increase in overall thermal performance when compared to uninsulated flooring, even when compared to specifications B and C with substantially increased wall and ceiling insulation and building sealing levels.

When compared to waffle pod construction, with the values currently permitted in all NatHERS software, Kingspan Kooltherm® K3 Floorboard either matches or improves overall results, irrespective of the specification level of walls and ceiling insulation.

Specifying Kingspan Kooltherm® K3 Floorboard potentially increases a dwelling’s rating by up to 1 Star and significantly contributes to achieving a minimum 6 Star rating for regulatory compliance without the need to change building design or boosting walls and ceiling insulation levels.

There is no doubt the impact that Kingspan Kooltherm® K3 Floorboard under slab insulation has on building performance. As a ‘one-fits-all’ insulation solution, Kooltherm® K3 can help achieve a 6 Star energy efficiency rating irrespective of climate zone or orientation.

References • Kooltherm® K3 Floorboard Study. Prepared for Kingspan Insulation

Pty Ltd by Graham Energy (graham.energy) October 2016• Kooltherm® K3 (kingspan.com/au/K3) • Victorian Building Authority – Six Star Standard

(vba.vic.gov.au/consumers/6-star-standard)

“Even with boosted wall and ceiling levels neither of the alternative constructions could improve up to the level of the Kingspan Kooltherm® K3 Floorboard option.”

11

About Kingspan Kooltherm® K3 Floorboard

Kingspan Kooltherm® K3 Floorboard is a super high performance, rigid, thermoset phenolic insulation with a fibre free, closed cell insulation core. This core is sandwiched between two layers of tissue based facing. The facings are autohesively bonded to the insulation core during manufacture.

Kingspan Kooltherm® K3 Floorboard is manufactured without the use of CFCs / HCFCs and has zero Ozone Depleting Potential (ODP) and low Global Warming Potential (GWP).

Product R-values

Key Benefits:

• Helps increase a project’s rating by up to 1 Star

• ‘One-fits-all’ insulation solution (saves on design development costs)

• Resistant to the passage of water vapour

• Easy to handle and install

• Compliant with AS/NZS 4859.1

Product Data

Thermal Conductivity (λ-value)

0.020 W/m K (Insulant thickness ≥ 45 mm)

0.021 W/m K (Insulant thickness 25 - 44 mm)

Product Dimensions 2400 mm x 1200 mm (2.88 m2)

Product Thickness 25, 30, 40, 50 mm

Product Thickness Product R-Value

25 mm R1.2

30 mm R1.4

40 mm R1.9

50 mm R2.5

Masonry cavity wall


K8 Cavity Board


K3 FloorboardDamp proof membrane

Compacted aggregate/sand blinding

Concrete slab

Separation layer (e.g. polythene sheet)

Insulation for solid concrete ground based floors

Kooltherm® K3 Floorboard is a super high performance under slab insulation available in various thicknesses to help achieve 6 Star thermal performance.

Kingspan Insulation Pty LtdTel: 1300 247 235

Email: [email protected]

® Kingspan, Kooltherm and the Lion Device are Registered Trademarks of the Kingspan Group plc in Australia and other countries. All rights reserved. © Kingspan Insulation Pty Ltd

Kingspan Insulation Pty Ltd reserves the right to amend product specifications without prior notice. The information, technical details and fixing instructions etc. included in this literature are given in good faith and apply to uses described. Recommendations for use should be verified as to the suitability and compliance with actual requirements, specifications and any applicable laws and regulations. For other applications or conditions of

use, Kingspan Insulation offers a Technical Advisory Service the advice of which should be sought for uses of Kingspan Insulation products that are not specifically described herein. Please check that your copy of the literature is current by contacting us or visiting www.kingspaninsulation.com.au

Contact Details

General EnquiriesTel: 1300 247 235

Email: [email protected]

www.kingspaninsulation.com.au

The impact of under slab insulation on building performance

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