Moisture and Mould in Buildings

7/25/2019 Moisture and Mould in Buildings

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Moisture and Mould inBuildings

Charlotte Gudum

M. Sc. Engineering, Ph.d.


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28-04-2015

Charlotte GudumConsulting Building Engineer M.Sc., Ph.D

1996 M. Sc. Insulation of cold pipes, using

Hygro Lock system to avoid condensation

problems.2002 Ph.D.Moisture transport by convection

inside building envelopes.

2002-2005 Consulting Engineerby Birch &

Krogboe (now Alectia), building renovation

2005-2011 Consulting Engineerby Bygge- og

Miljteknik.

2011- Consulting Engineer by Golder. Working

with moisture problems, indoor climate, PCB,

building physics....


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Facts about mould fungus

Mould exist everywhere in thenature.

>2000 different sorts of mould.

Inside the building, mould effects

the health

Some are more toxid than others,

but basicly mould must be hold on

a minimum level in buildings.

28/04/2015 /Side 3


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In order to grow most mould

species require:70 % RH+

fairly warm environment >5 C40C

Time (3-4 weeks)organic material - but only

require small amounts to live on

Mould may cause health problemsalso after they are dead soconsequently remains should beremoved

Conditions for mould growth


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The moisture might be caused by:

rising damp

condensation inside a construction

built in moisture (i.e. moisture fromthe building process)

changes of constructions withoutpaying notice to the risks of

jeopardizing or changing theventilation etc.

the behaviour of the occupant, e.g.due to lack of ventilation or drying ofclothes inside the dwelling

accidents, e.g. pipe breakage or fire,

where constructions are soaked

Conditions for mould growth


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Mould and health

Irritation in the eyes, nose and lungs

Head each

Tiredness

Problems of concentration

Dizzyness

Coughing

Skin eruption

Infektion in the air ways.

Development of asthma, (especially

children).

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A typical Danish apartment built in 1970

with a leaky pipe or two.

Kilde: Peter Thompson, Bygge- og Miljteknik


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Mould under the floor after a leak.

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Side 8Kilde: Peter Thompson, Bygge- og Miljteknik


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Leaking roof coverings

Quite a few of the most severecases with mould growth inbuilding are caused by leakingroof coverings.

The reasons might be eitherthat the leak(s) is not seen untilthe penetrating water hascaused additional damages ormore often - thatmaintenance is neglected.

Penetration of water to theinterior of the roof will nodoubts cause considerablemould growth.



10/63Extensive hiddenmould growth


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Mould growth in buildings is often hidden from view


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13/63Mould growth due to cold bridging



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Inside insulation on a cold facade

New insulation,lowers the

temperature,

rises the

relativehumidity and

causes mould.

Side 14

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Sub-cooling of surfaces inside roofs

In ventilated roof the inner side ofthe roof is quite often boards orplywood.

Radiation to the sky in clear nightsmight result in sub-cooling of the

inner surface that brings thetemperature below the dew point i.e.condensation will occur.

The condensation facilitates thegrowth of mould and especially onplywood the growth can be

considerably.

In Finland and Sweden plywood forroofs are now treated with woodpreservatives in order to avoid theproblem.



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Typical Danish terraced houses (120) built

in 1970and renovated wrongly in 1995...



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Attic became cold after increase of insulation.

28/04/2015 /Bygge- og Miljteknik

A/S

Side 17

-10 -5 0 5 10 15 20 25 30C

0

5

10

15

20

25

100

pct.RF

10

60

50

40

70

8090

20

Gram vand per m3luft

30

Gram water/m3

air


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Not aging resistant vapour retarder


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Outside insulation on a facade


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A gym with cawl space in the middel


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The dilemma of basement/crawl space

28/04/2015Side 27


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Attention renovating crawl space!

Risk to lower the temperature and

rise the RH when

More insulation around the hot

pipes.

More insulation in the ceiling (ofthe crawl space)

Risk to rise the RH

By outdoor ventilation in summer

When closing the ventilation in

winther

28/04/2015Side 28


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Office smells of mould

Sli i i l


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Slimsvamp growing in a crawl space


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Moisture and mould control in basement


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Moisture and mould control in 1th floor


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The terrain leads water into the wall and

basement


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F il id f 2007


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Family residence from 2007

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Side 42


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Mould on the roofing near the

openings for ventilation

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Side 43

With t th i t th b i k ll


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Without eaves the rain wets the brick wall.

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Side 44


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Protect the Plasterboard from concrete


Moisture in the building process


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Moisture in the building process

Concrete and

brick-walls are

made with water

Drying out costs

time, -and takeslong time.

The surplus of

water migratesto other

materials

Side 46

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Exchange of moisture between materials


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Exchange of moisture between materials

Sorptionscurves


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Sorptionscurves


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P t ti f t i l it


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Protection of materials on site.


Factory The prefabrication process


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Factory. The prefabrication process

TK is an independent watchdog unit which monitors manufacturers of

prefabricated timber elements in Denmark.

The timber is stored indoors at the factory and moisture levels monitored

throughout the manufacturing process..

But it's not here that things go wrong..


Protection of buildings on site


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Protection of buildings on site



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Most people would not expect that brand new

buildingsunder construction now, would have

moisture and mould related problems.

The roof had to be rebuild


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The roof had to be rebuild


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Mould removal


Superheated steam the Micro Clean Method


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Superheated steam the Micro Clean Method

The energy exerted when the superheated

steam condensates on the treated surfacekillsthe mould

The mould is then removedfrom the surfaceby treating with a cotton cloth attachment onsteam head

The surfaces are cleaned using a vacuumcleaner with a micro filter before and aftertreatment with superheated steam

The mostly used mould-cleaning method inDenmark


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A very small

choice of themany

chemicals

available formould

remediation


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c

Sand- or iceblasting:Always incurs extra

cleaning costs


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Aftermechanical

cleaning:

Surfaces areoften treated

with the Micro

Clean method

afterwards to

remove all

mould

Example 2 Penthouse - Copenhagen


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renovation cost twice the building!

Example 2Penthouse - Copenhagen


How to manage moisture on the site


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How to manage moisture on the site

Vejledning om hndtering af fugt i

byggeriet

http://www.ebst.dk/file/154179/vejl

edning-fugt_i_byggeriet.pdf
http://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdfhttp://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdfhttp://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdfhttp://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdfhttp://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdfhttp://www.ebst.dk/file/154179/vejledning-fugt_i_byggeriet.pdf


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Moisture and Mould in Buildings