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10 May 2016

Checklist - How to Analyse Dampness

Checklist - How to Analyse Dampness Checklist - How to Analyse Dampness

Checklist regarding causes of odors, moisture and mold in a building:

The following checklist may help you with the inspection of a building, when you have to decide what the presumed cause is of an error, odor, discoloration, moisture, mold growth, etc.

  • Smell of mold
  • Discoloration
  • The exterior moisture protection of the building
  • Moisture in roofs, terraces and attic
  • Moisture in basements and decks
  • Ventilation
  • Moisture in wetrooms
  • Moisture in the living room, kitchen, offices, classrooms and the like

Smell of mold:
The smell of mold is usually caused by Aktinomyceter (bacteria) or growth of molds. The mold which releases the substance geosmin etc. smells bad and a lot.

Discoloration:
Discoloration may be indicative of:

  • Moisture that draw salts out of the wall, mostly of whitish appearance.
  • Moisture, which result in mold growth.
  • Thermal bridges where dust and other particles can settle. (Often associated with short-term condensation)
  • Binding of particles to the walls above radiators or around an airsupply.

Suddenly blackening is often caused by a combination of these last two mentioned problems, in the context of soot from poor candles or other combustion in the room (petroleum or oil stoves and fireplaces).

The exterior moisture protection of the building:

The building and the construction moisture condition is dependent on the building envelope, and the surrounding terrains moisture conditions. The following causes of moisture shown in the list below, where the emphasis is on whether the design is critical, and/or if maintenance is poor:

  • Moist terrain, possibly with a slope towards the plinth.
  • Missing or covered ventilation of basements / crawlspaces.
  • Cracks in walls and joints between walls and between walls and windows.
  • Flat roofs / terraces with standing water, steam bulging, leaking penetrations or hidden gutters.
  • Sloping roofs with moss coverings
  • Missing or defective, weathered roof tiles.
  • Rainwater is not removed effectively without soaking of the walls or the soil around the plinth.
  • Lack of ventilation of after insulated outer walls.
  • Surface of exterior walls is to air/damp-proof – always use KefaTherm Exterior.

The photo shows a cracked outer wall, which may lead to inadequate wetting of the structure. It may be the reason that the limit for mold growth is exceeded inside on the wallpaper:


Moisture in roofs, terraces and attics:
Visible, noticeable or measurable increase of moist in the materials (with subsequent growth) are indications of:

  • Leaks in the roofing or terrace layer, where the penetration of moisture is not removed from the construction by ventilation.
  • Leaks in coverings and interior gutters.
  • Driving rain or drifting snow at the eaves, gables or roof ridge.
  • Rising damp due to leaking vapor barrier.
  • Inadequate ventilation of the insulation in the ceiling (eg in para or attic.
  • Unstable joints and leaks in the sub roof and vapor barrier.
  • Building moisture.
  • Leakage in installations.
  • Ventilation ducts ending in the attic.
  • Lack of ventilation of an after isolated attic.

The photo shows a built-up roof with standing water, which is a major risk of water damage:




Visible, noticeable or measurable increase of moist in the materials (with subsequent growth) is indication of:

  • Leakage of water on the basement exterior walls, due to a non-drained terrain (moisture seen in local parties, particularly below ground, dry partition walls).
  • Internal insulated walls where moisture from the wall cannot diffuse into the basement, and where at the same time the insulation contains organic materials.
  • Moisture from the ground by capillary transport or diffusion in flooring, interior walls or exterior walls.
  • Condensation from the inside, on an uninsulated exterior wall or floor (in summer below ground in winter above ground, while the partition walls are dry).
  • Construction moisture.
  • Water waste or moistening from renovations eg floors / deck with clay deposits or organic fillers.

The photograph shows an example of rising damp in a basement - could also be seen in a normal house

Especially ground deck:

  • Lack of insulation under the concrete slab.
  • Lack of drainage.
  • Building moisture, especially on not vented or diffusion proof flooring, eg PVC glued on concrete.

Especially crawl space:

  • Lack of dense layer, such as plastic film on the substrate.
  • Leakage of water on basement exterior walls and the wear layer that is not drained (moisture seen in local parties, least of terrain, partitions walls are dry).
  • Condensation from the inside on uninsulated exterior wall or floor (in summer below ground in winter above ground, while the inner walls are dry).
  • Lack of ventilation through vents.
  • Central heating pipes, that drives moisture up into the crawl space.
  • Building moisture.
  • Wooden structures and wooden or plasterboard or building dust exposed in crawl space poses a risk of mold growth.

Ventilation:

To poor ventilation and low extraction of moisture-emitting devices can result in high relative humidity in the rooms, which particularly allows growth on thermal bridges. The indikation of This show up as:

  • More than approximately 4 grams of moisture per. m3 of air relative to the ambient air humidity with the least occurring ventilation.
  • Less performance than the requirements of the BR 95 (Building Regulations) for housing. That is, air changes less than about 0.5 times per hour in homes (though less than 0.7 in small rooms). In densely occupied spaces such as schools, less than about 1.5 times per hour.
  • Fans completely stopped or during periods when there is load. In multi-storey buildings, ventilation should generally not be stopped at night.
  • Dirty impeller, heating coils, filters, ducts, supply and exhaust valves and intake (column valves).
  • The growth of molds and bacteria (Legionella) in humidifiers (occurs rarely in steam humidifier).
  • The growth of molds and bacteria (Legionella) around refrigeration plants where moisture condenses. It can be in central facilities or locally in the rooms.

    The photo shows an air extractor that is set to with dirt. This can be a contributing factor to rising damp and mold growth in homes and should give rise to a control measurement of the magnitude of the exhaust ventilation air:

 

Moisture in wet rooms

Visible, noticeable or measurable increase of moist in the materials (with subsequent growth) are indications of:

  • Excessive use of bathing and drying clothes in relation to ventilation.
  • Inadequate ventilation (exhaust ventilation).
  • Thermal bridges, often in the corners or on the structural core including ceilings, where insulation is missing and at window sills.
  • Water leakages in the floor covering around the bath installation for example, by the drain
  • The ascent of moisture from the ground in the deck or exterior walls.
  • Penetration of poorly drained terrain (see basements).
  • The penetration of water from heavy rain in leaky or poorly maintained exterior walls and windows.
  • Leakage in the hidden water installations.
  • Building moisture.
  • Insufficient water-resistant materials and structures.

The photo shows a bathroom where there is a leaking seal around a pipe. Water is fed into the construction and pile up. Underlying or adjacent room or structures with organic materials will have a high risk of water and mold damage:


Moisture in the living room, kitchen, offices, classrooms and the like.
Visible, noticeable or measurable increase of moist in the materials (with subsequent growth) are indications of:

  • High humidity depending on season due to poor ventilation and / or excessive supply of moisture. This could be due to many people or drying clothes indoors, for example (non-condensing) dryer with no ventilation to the outside. The problems are often compounded in winter if kept too low temperature in the rooms.
  • Lack of ventilation, including missing or defective extractor.
  • Thermal bridges often in corners or on the structural core including ceilings, where insulation is missing.
  • Moisture from leaks in the roof terrace, attic, roof construction.
  • Water from leaks in the overlying room or adjoining rooms (wetroom).
  • The ascent of moisture from the ground up in the deck or exterior walls.
  • The penetration of humid air possibly contaminated with mold from the crawl space.
  • Penetration of poorly drained terrain.
  • The penetration of water from heavy rain in leaky or poorly maintained exterior walls and windows.
  • Leakage in water installations in walls or under floors.
  • Building moisture..

The photo shows mold growing on both sides of wallpaper on an exterior wall. The moisture coming from the outside, because outside is a coating that does not diverts the rainwater sufficient:

Read 2388 times Last modified on Wednesday, 11 May 2016 21:44
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