how to maintain proper drainage and ventilation in old homes

Making sure your house has proper ventilation and drainage is integral to keeping it in good shape. A relatively easy way to increase ventilation under the house is to replace the original small terracotta or ornate metal vents with modern brass mesh vents. Here are some other tips to consider for the preservation of your home or building.

how to maintain proper drainage and ventilation in old homes

Keeping window grooves clear

  • Old homes often have windows with drip grooves under the sills. These must be kept clear so that water drips down rather than flowing along underneath the sills.
  • Defective flashing around doors or windows is another cause of damp problems. This is most commonly noticed under windows.
  • Where there is a flashing, there is usually a series of weep holes (small openings between bricks just above the flashing on the outside of the house) designed to allow the water to escape. These must be kept clean and open in order to function properly.
  • High ground levels outside a house can also cause water to come into the building. If the ground is higher than the floor or damp-proof course, damp problems should be expected.
  • Lower the ground level of your home if water is coming into the building. On large land holdings this is normally quite easy, but if the house is close to other new buildings space may be tight, and small retaining walls and drainage systems may have to be built.

Pay attention to drainage and ventilation

If drainage around the house is inadequate, water may sometimes flow into or under the building. This can be very serious, in some cases causing erosion around the base of the house.

  • Divert the flow of water by installing surface drains, such as spoon or grated drains.
  • If the ground around a house is quite boggy and soft, and incapable of supporting paving — problems usually caused by seepage or inadequate drainage — then sub-surface drains may need to be installed.
  • Sub-surface drainage is also needed where walls are used to retain earth.
  • Good ventilation prevents mould and musty smells.
  • Minimum levels of ventilation are set down in building regulations.In most cases, one twentieth of the floor area of a room must be set aside as an openable door or window area.
  • Bathrooms and kitchens should be particularly well ventilated to allow steam and cooking odours to escape to the outside. An exhaust fan, ducted to the exterior, is the ideal way to ensure this.
  • Underneath the house, bad ventilation can cause timber to rot and mould to flourish. Subfloor ventilation is essential.
  • Most timber-frame houses have few problems as they are built on piers, usually with two sides and the back exposed to allow free air flow.
  • If the sub-floor area has been enclosed, then vents will be needed at about 1.8 metre (six foot) intervals.
  • In brick homes, terracotta or brass mesh vents are needed about every 1.8 to two metres (six to 6 1/2 feet) around the perimeter.
  • As internal walls extend to the ground, holes should be provided below floor level to allow free air flow by knocking out bricks.
  • Do not be tempted to use the underneath of your house as a storage area as ventilation can be severely affected.
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