Do I have rising damp or penetrating damp?

Many of us will have experienced damp or condensation in our homes at some point. While it’s easy to pass these things off as no big deal, both can eventually lead to property issues if not protected against.

Living in a property with damp can contribute to health problems so it’s important to resolve the issue as soon as possible. Furthermore, the worse the situation gets, the more it’s likely to cost to remove and repair any damage.

The first step to treating damp is to identify whether you have rising damp or penetrating damp.

Rising damp

Rising damp is caused by ground water moving up through a wall or floor. While most walls and floors allow some water in, it’s usually stopped from causing damage by a barrier called a damp-proof course or damp-proof membrane.rising damp

Modern homes tend to have both as part of new building regulations but older buildings may not have them or they may have worn or become damaged over time.

Rising damp can also happen when the level of the ground outside your home is higher than your damp-proof course or there isn’t proper drainage available.

Signs of rising damp include:

  • Damaged or rotting skirting boards or plaster.
  • Peeling paint or wallpaper, often with wet patches.
  • Rising damp may dissolve soluble salts from the ground which can then crystallise and form a white powder-like substance.
  • If the problem is coming up from the floor, you may notice floor coverings lifting or damp patches.
  • A tide line of yellowish or brownish staining or brown plaster in the lower area of your wall above your skirting board.

How to treat rising damp

If you’ve discovered that your rising damp has been caused by a blocked cavity wall, you can unblock it. This is something you can do yourself or you can hire a professional if you wish.

Install a damp proof course – this can include water repellent chemicals, pore blocking salt mixture and osmotic water repellence.

Penetrating damp

Penetrating DampPenetrating damp is caused by water leaking through walls. This type of damp may expand across your walls or ceiling and usually happens in a horizontal movement.

This type of damp is caused by structural problems in a building, such as faulty guttering or roofing or cracks in the walls. It can also be caused by internal leaks, such as pipes under the sink or bath. Unfortunately, this usually means that walls or roofs are regularly soaked with water. Below ground penetrating damp is caused by ground water penetrating through the masonry.

Signs of penetrating damp

  • Penetrating damp usually shows up through damp patches on walls or ceilings, which may darken when it rains.
  • Growing circles of damp on walls or ceilings.
  • Blotchy patches on walls.
  • Wet and crumbly plaster.
  • Drips and puddles.

How to treat penetrating damp

The key thing is to eliminate moisture at source. This can be tricky but you can do it in a number of ways including resealing windows and exterior door frames, repointing any crumbling or missing mortar between bricks and applying a water repellent coating to the masonry. There could be an obstruction or debris in your cavity wall which is bridging dampness from the outer skin of the property to the inner skin.

Treating below ground penetrating damp is more complicated and may involve the application of cementitious survey in the masonry or the use of a plastic membrane.

Still Unsure?

If you find you are asking yourself “do I have rising damp or penetrating damp” or you believe you have problem, please feel free to book a survey online and we will be able to advise you about damp-proofing options.

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