how to stop designing mouldy buildings€¦ · how to stop designing mouldy buildings (and...

How to Stop Designing Mouldy Buildings (and mainstream the thermal bridge)

Simon McGuinness, MRIAI

TGD - D.2 Mould growth & surface

condensation

The key factor used in assessing

the risk of mould growth or

surface condensation in the

vicinity of thermal bridges is the

temperature factor (fRsi).

For dwellings, the value of fRsi

should be greater than or equal

to 0.75, so as to avoid the risk

of mould growth and surface

condensation.

TGD - D.2 Mould growth & surface

condensation

The key factor used in assessing

the risk of mould growth or

surface condensation in the

vicinity of thermal bridges is the

temperature factor (fRsi).

For dwellings, the value of fRsi

should be greater than or equal

to 0.75, so as to avoid the risk

of mould growth and surface

condensation.

For fRsi > 0.75

Tsi > 15degC

TGD - D.4 Calculation procedures

The calculation procedure to

establish temperature factor

(fRsi) is outlined in BRE IP 1/06.

Details should be assessed in

accordance with the methods

described in I.S. EN ISO:10211.

Which in turn references I.S. EN

ISO:13788 as “indispensable for

the application of this

document.”

TGD - D.4 Calculation procedures

The calculation procedure to

establish temperature factor

(fRsi) is outlined in BRE IP 1/06.

Details should be assessed in

accordance with the methods

described in I.S. EN ISO:10211.

Which in turn references I.S.

hEN ISO:13788 as “indispensable

for the application of this

document.”

ISO hEN 13788: 2012 (December 2013)

Walls, Floors, Ceilings

fRsi calculation

0.25 m2K/W surface resistance

0.25 m2K/W surface resistance

0.25 m2K/W surface resistance

ISO hEN 13788: 2012 (December 2013)

0.10 ^

0.13 >

0.25 ^

0.25 >

ISO hEN 13788: 2012 (December 2013)

0.10 ^

0.13 >

0.25 ^

0.25 >

Gable/Eaves cavity wall example

ACD 1.09 ACD 1.15

Gable/Eaves cavity wall example

ACD 1.09 (Eaves) and

ACD 1.15 (Gable)

Under construction

In Dublin in 2015

Gable/Eaves cavity wall 3D model

3-D Thermal Modelling – Fails fRsi

Add 2.5 thermal blocks & mineral wool

Thermal Modelling – barely passes fRsi

What does the responsible educator do?

Double-checked the standards

Revised the syllabus

Warned previous Thermal Modeller graduates

Advised the regulators

Advised the RIAI

Issued three blog postings on BRegsForum

Tweeted on social media

Asked for clarification from the Minister

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√

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Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

“I refer to the reply to Question

No. 788 of 15 April 2015 which

addressed the approach to

calculating the temperature factor

in the vicinity of thermal bridges at

junctions and around openings in

accordance with Appendix D of

Technical Guidance Document L

2011. ….”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

“I refer to the reply to Question

No. 788 of 15 April 2015 which

addressed the approach to

calculating the temperature factor

in the vicinity of thermal bridges at

junctions and around openings in

accordance with Appendix D of

Technical Guidance Document L

2011. ….”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

”… A surface resistance value of

0.25 is only used in very specific

situations as outlined in section 4.4

of the EN ISO 13788 standard

which is of rather limited relevance

in this context and, for that reason,

it has not been referenced at

Appendix D of TGD L 2011 or

referred to in the reply to

Question No. 788 of 15 April

2015.”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

“I refer to the reply to Question

No. 788 of 15 April 2015 which

addressed the approach to

calculating the temperature factor

in the vicinity of thermal bridges at

junctions and around openings in

accordance with Appendix D of

Technical Guidance Document L

2011. ….”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

”… A surface resistance value of

0.25 is only used in very specific

situations as outlined in section 4.4

of the EN ISO 13788 standard

which is of rather limited relevance

in this context and, for that reason,

it has not been referenced at

Appendix D of TGD L 2011 or

referred to in the reply to

Question No. 788 of 15 April

2015.”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

“I refer to the reply to Question

No. 788 of 15 April 2015 which

addressed the approach to

calculating the temperature factor

in the vicinity of thermal bridges at

junctions and around openings in

accordance with Appendix D of

Technical Guidance Document L

2011. ….”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

”… A surface resistance value of

0.25 is only used in very specific

situations as outlined in section 4.4

of the EN ISO 13788 standard

which is of rather limited relevance

in this context and, for that reason,

it has not been referenced at

Appendix D of TGD L 2011 or

referred to in the reply to

Question No. 788 of 15 April

2015.”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

“I refer to the reply to Question

No. 788 of 15 April 2015 which

addressed the approach to

calculating the temperature factor

in the vicinity of thermal bridges at

junctions and around openings in

accordance with Appendix D of

Technical Guidance Document L

2011. ….”

Minister of State for the

Environment, Community and

Local Government (Deputy Paudie

Coffey)

”… A surface resistance value of

0.25 is only used in very specific

situations as outlined in section 4.4

of the EN ISO 13788 standard

which is of rather limited relevance

in this context and, for that reason,

it has not been referenced at

Appendix D of TGD L 2011 or

referred to in the reply to

Question No. 788 of 15 April

2015.”

?

Can the Design Certifier Rely on

the ACDs to deliver a Mould-free

Compliant Design?

On the basis of our work in the last

12 months, it is significantly less

than “certain” that he or she can.

Can the Design Certifier Rely on

the ACDs to deliver a Mould-free

Compliant Design?

On the basis of our work in the last

12 months, it is significantly less

than “certain” that he or she can.

How did it impact on the DIT nZEB Retrofit

Project 2015?

Current BER: 363 kWh/m2a

Target: 45 kWh/m2a

Saving Per Unit: 318 kWh/m2a

Cabra alone: 3,800 similar houses

Total Savings: 1,208, 400 kWh/m2a

Money Saved: €9million per year

Would fund 200 retrofits per year

In 19 years it would be complete

How did it impact on the DIT nZEB Retrofit

Project 2015?

Current BER: 363 kWh/m2a

Target: 45 kWh/m2a

Saving Per Unit: 318 kWh/m2a

Cabra alone: 3,800 similar houses

Total Savings: 1,208, 400 kWh/m2a

Money Saved: €9million per year

Would fund 200 retrofits per year

In 19 years it would be complete

Thermal Modelling used to check for fRsi

Thermal Modelling used to check for fRsi

Thermal Modelling used to check for fRsi

How to reduce the cost of retrofit …

€560 per ACD x 178 ACDs x 2 U-values = €100,000

Would take 3 months and employ 5 researchers, or

€10,332 cost per home x 1.3 Million homes = €13,431,600,000

How to reduce the cost of retrofit …

€560 per ACD x 178 ACDs x 2 U-values = €100,000

Would take 3 months and employ 5 researchers, or

€10,332 cost per home x 1.3 Million homes = €13,431,600,000

One of these

is “cost

optimal”

The Dublin School of Architecture and

Building looks forward to working with

Government and the construction industry to

resolve all the technical issues necessary to

achieve nZEB Retrofit safely, cost effectively

and speedily. By working together, we are

confident we can achieve our national targets.