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Households

Damp

CONTEXT

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Water is one of the elements that generate the most constructive pathologies, if it is not under control. Damp is one of them and in homes it may have three different sources:

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  • Damp caused by filtrations or capillarity is caused by excess water on the ground or from the sanitation system. Water is absorbed by the building envelope in accordance with its permeability and porosity, also through building seals, cracks or fissures. The water is absorbed by the materials along with hygroscopic salts that, when they rise, evaporate and impregnate the walls. When a wall cannot store more water, black stains and other problems arising from excessive humidity appear, such as residues, carbonates and sometimes fungus on the surface.
  • Damp due to accidents is due to the poor operation of the water evacuation and supply installations and may affect other constructive and structural elements. A possible cause may be a broken pipe. An inappropriate action on the building materials and elements, such as an impact or a change in use, may also be a cause of poor operation that generates damp.
  • Condensation damp: If a possible leak from the exterior or small leaks from the interior installations have been discarded, the possibility of the cause being a condensation problem must be contemplated. Condensation damp occurs when the humidity contained in the air is converted into liquid water when it meets a cold surface. Generally it occurs at points where there are heat bridges, that is, points on walls where the thermal insulation is less.
    The factors that favour its appearance include deficient ventilation (air from closed places may be two to five times more contaminating than that from the exterior, creating a feeling of discomfort) and the accumulation of water vapour on permeable surfaces such as gypsum and paint. The kitchen and the bathrooms are the places most susceptible to the appearance of damp.
    Poor regulation of heating with sharp variations in temperature may also result in condensation problems on walls or windows.

Damp is the ideal medium for the appearance of fungus and mould in the home and the production of fungal toxins that can cause respiratory problems and allergic reactions.

A strong presence of fungus and fungus spores in the air may produce allergic reactions, asthma episodes, infections and other respiratory problems for people, especially children, the elderly and pregnant women. Typical symptoms are respiratory problems, nasal and frontal sinus congestion, burning eyes, dry cough, neck pain, skin irritation and constant headaches.

 

OBJECTIVE

  • Improve the interior environmental quality of the home and therefore the quality of life of its residents.
  • Suitably maintain the home to prevent water filtrations and the need for interventions.

PROPOSALS AND RECOMMENDATIONS

Proposals and recommendations for users

Consider the building as a living structure that, like a vehicle, needs it parts to be changed when they wear out. If the necessary maintenance work is not carried out, the water will enter the interior of the building, creating problems that are more difficult and expensive to solve. Accordingly, maintenance is the best form of prevention.

Filtration damp

  • Periodic review of the condition of the elements and renovation or repair of damaged elements.
  • Uproot plants from terraces and roofs.
  • Clean all problem areas. Something as trivial as sweeping the terrace in the long run prevents downpipes from being obstructed and filling up when it rains. The gutters of roofs and other structures must also be kept clean.
  • Replacement of deteriorated materials. This encompasses the good maintenance of the condition of paint on railings (and prevents them from rusting) to the replacement of asphalt roof tiles and checking structural joints and seals. The Building Record includes a maintenance plan that specifies when and where intervention is necessary to prevent damage. If the community does not have a Building Record, it is advisable to hire a technician to act as the building’s “general practitioner”.
  • Replace windows/exterior woodwork that do not fit properly to guarantee the waterproofing of the home.

Condensation damp

  • If the condensation appears on interior surfaces, thermally insulate and replace windows that do not fit properly and study in each case the construction details or reduce the water vapour pressure, ventilating the space (see "Ventilation"). It is advisable to have double (or triple) glazing with noble gases like argon and laminated glass. Glass with a chamber that does not contain SF6 (sulphur hexafluoride) should be chosen. It must be taken into account that, in general, increasing the airtightness of homes usually makes the problem worse that it is in homes that have continuous ventilation, even if it is not wanted. There is more condensation in airtight buildings.
  • If the condensation is interstitial within the wall, introduce vapour barriers or an air chamber ventilated to the exterior.
  • Periodic manual ventilation of the wet rooms of homes: (see "Ventilation").
    • In the bathrooms the main problem is from the steam that hot water gives off from the shower and the bath. To prevent the appearance of fungus it is advisable to ventilate properly after showering and use special paint for wet areas. Pay attention to uncontrolled heat exchanges because too much ventilation may result in too much cooling.
    • In the kitchen, the concentration of steam is from the hob, so an extractor hood should be used even if odours and smoke are not produced; for example when boiling water. It is advisable to use special paint for wet areas. If the problems persist, it is possible that the extraction system is not working correctly or is not powerful enough, so the first measure to be adopted must be improving ventilation and preventing heat bridges, in addition to repairing or replacing the hood.
      If damp persists, it will be necessary to install an additional artificial extraction system or dehumidifiers.
  • Good regulation of heating without sharp changes in temperature.
  • Good insulation on the facades, in the pipes and other cold surfaces to reduce condensation. This insulation will preferably be done using organic or mineral materials, given that they are breathable and enable the removal of condensation. In this case, the materials are cork, flax, hemp, wood fibres, wool or cotton blankets, or cotton, cellulose or mineral (glass or rock) wool flakes.
  • Avoid heat bridges in woodwork and glass. In the case of an existing building, heat bridges may be identified by means of a thermographic study of the envelope, identifying the cold points of the exterior walls and the specific resolution mechanisms to be applied in each case.
  • Elements to avoid, due to the major degree of humidity they contribute to the interior of the home:
    • frequent floor mopping,
    • butane gas heaters. If one is used, ventilate the room for five minutes every two to three hours to lower the level of humidity.
    • drying clothes inside the home,
    • presence of plants and aquariums,
    • excessive level of occupation of the home.

Accidental damp

  • Check the condition of elements and systems. When broken pipes are detected, they must be repaired immediately to prevent water affecting other constructive or structural elements.


Proposals and recommendations for the administration

Councils can detect the most significant shortfalls by means of various tools like building technical reports (ITEs), among others, and propose the most suitable intervention. Some of the actions that they can implement are:

  • Public awareness or education campaigns that foster the periodic ventilation of homes and the maintenance of buildings: cleaning and replacement of deteriorated materials.
  • Subsidies for the preparation of technical reports, which may be compulsory depending on the age of the building, in accordance with legislation in force.
  • Assessment and support to help cohabitation units:
    • Access aid for renovations (both that offered by the Catalan Housing Agency and that provided by the local administrations).
    • The incorporation of anti-damp measures (special paint in risk areas, improvements to extraction devices, etc.) and improve thermal insulation in public and private residential construction projects.
  • Establishment of municipal aid for renovations to foster:
    • The interior improvement of homes, in cases in which an intervention is necessary to guarantee habitability.
    • The improvement of buildings that incorporate solutions to these problems.

REFERENCE EXPERIENCES

Information only available in Catalan

 

 

 

LEGISLATION

STUDIES AND TECHNICAL DOCUMENTATION

  • Departament de Medi Ambient i Habitatge de la Generalitat de Catalunya. 2010. Guia de la renovació energètica d'edificis d'habitatges: envolupament tèrmica i instal·lacions.
  • Embuena, M., Tractament d'humitats. Tècniques d’intervenció. Exemples d’aplicació. 2n Simposi “Tradició i innovació en rehabilitació”. Col·legi d'Aparelladors, Arquitectes Tècnics i Enginyers d'Edificació de Barcelona.
  • Wolkoff, Peder, 2018. Indoor air humidity, air quality, and health – An overview. International Journal of Hygiene and Environmental Health. Volume 221, Issue 3, April, Pages 376-390.

OTHER LISTINGS OF THE GUIDE

  • Àmbit Habitatge. Ús i manteniment dels habitatges. Fitxa "Ventilació"
  • Àmbit Equipaments. Condicions favorables. Fitxa "Qualitat de l´aire interior"

More information about addressing the Public Health Service: entornurbasalut@diba.cat

Date of last update:
dt., 11 de maig 2021 15:16:39 +0000