Is it Rising or Penetrating Damp?
We have all experienced condensation or damp in our properties at one time or another. Residing in a home with dampness present can be risky for the health of everyone living in it. Dampness in a property can come from all sorts of sources. It is crucial that you understand how the property is constructed, especially with older buildings. Damp can lead to issues with the property if not treated, which is why it is essential to address the issue as early as possible. The longer the issue remains untreated, the problem will surely worsen resulting in much more expensive repairs and even replacement.
Determining whether the problem is rising or penetrating damp is critical. The misdiagnosed damp issue will result in ineffective damp proofing treatment and measures.
Rising Damp: What is it?
Rising damp is a form of damp that is somewhat rare and affects building walls. Rising damp happens when moisture coming from the ground elevates through the walls as a result of capillary action. Water in the ground is absorbed through very small tubes in bricks which are comparable to straws. The most common sign of rising damp occurrence is a tide mark on the wall. The water that rises up the wall contains soluble ground salt as well, which are deposited as damp evaporates within the masonry.
These salts will cause the paint to bulge or bubble with fluffy white deposits on the surface. There are two types of salt involved – hygroscopic salts (nitrates and chlorides) which draw moisture continuously and should be treated immediately, and sulphates which cause the white crusty patches on the wall.
Rising damp is often misdiagnosed and confused with condensation, but there is a way to identify them correctly. The most reliable way to discern between rising damp and dampness due to condensation is to compare moisture content in the masonry or mortar. If the inside of the wall is damp, it is rising damp. An electrical moisture meter can be used to identify the moisture content. Rising damp can rise up to 1.5 metres or higher in rare cases.
Damp Proofing Can Help Prevent
- Rising / Penetrating Damp
- Ingress of Water
- Salt Crystallization
- Plaster Breakdown
- Damp Staining
- Wet Rot / Dry Rot
What are the Causes Rising Damp?
Rising damp is only limited to ground floor levels, wherein the moisture from the soil permeates up the wall. The damp-proof membrane or damp-proof course is a barrier installed in the walls that inhibits the moisture from going up further. Modern properties most likely have the barrier installed but it may not be present in older buildings. If the damp-proof course is faulty, damaged or missing, the property is susceptible to rising damp. Rising damp also happens when the ground level outside is higher than the floor level inside the property. Rising damp is not always caused by outside sources. For the past 20 years, condensation has become the most common factor that produces rising damp in homes as well.
What are the Symptoms and Signs of Rising Damp?
Rising damp starts to form mould growths in timber, which causes it to rot. Green, white and black mould growths are present. Deterioration of paint and blistering or peeling of wallpaper are also indications of rising damp. Dark patches that are damp to touch can be an obvious sign as well. Outside walls may have discolouration. Salt stains begin to show up on the walls and the mortar may break. Rising damp can also cause iron and steel fasteners to rust. If the occupants of the building start to have respiratory illnesses, rising damp is likely the culprit due to the musty smell and spores from mould build-up. In severe situations, the affected wall may cause plaster or mortar to fall away and deteriorate. Rising damp can also cause tide marks, crumbling skirting boards and powdery, white substance on floors and walls (mineral deposits).
How is Rising Damp Treated?
If a blocked cavity wall is causing the rising damp, you can just simply unblock it. If your damp-proof course is perfectly fine, the dampness could be caused by the ground outside that has expanded above the damp-proof course (15 cm above the ground). You can dig away the excess soil from the outside wall beneath the damp-proof course level. If you do not have a DIY background, it is better to seek help from an expert.
A damp-proof course can also be installed to prevent the moisture from rising further. The barrier can include pore blocking salt mixture, water repellent chemicals and osmotic water repellents. If the damp-proof course or damp-proof membrane is faulty, you can replace them. Another solution is tanking the walls, which means the wall is given protection from moisture by sealing it.
Penetrating Damp: What is it?
Penetrating damp is a result of water seeping through the walls. Areas exposed to harsh weather conditions are prone to penetrating damp. If it rains frequently and comes to contact with the wall, saturation happens, which makes the isolated patches increase in size. Penetrating damp can affect all ages of properties, but older ones are more susceptible. This type of damp has two categories:
- Lateral Penetrating Damp typically takes place on external walls where the level of the external ground is higher than the floors inside the property. A perfect example of lateral penetrating damp is the basement.
- Vertical Penetrating Damp is caused by defects in the building and its poor maintenance. Some of the most common causes of vertical penetrating damp are blocked downpipes and guttering, roof defects, defective rainwater goods and leaking. These are also responsible for the occurrence of dry rot.
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What are the Causes of Penetrating Damp?
Penetrating damp is typically caused by structural issues in a property or building, like defective brickwork, faulty roofing covering or guttering, defective joints between walls and windows, leaking rainwater pipe, and crack on the walls. Internal leaks can also aggravate penetrating damp (e.g., pipes found under the bath or sink). Pointing, brickwork and render can be deteriorated with frost, age and physical damage. The absence of any form of waterproofing system will also cause penetrating damp.
Penetrating damp is an indication that the roofs or walls are frequently soaked with water. Penetrating damp below ground, on the other hand, is caused by water from the ground that seeps into and out the masonry.
What are the Symptoms and Signs of Penetrating Damp?
- There is ingress of water.
- Damp patches which can be found on ceilings and walls. These patches may darken when raining.
- Circles of damp that increase in size found on walls or ceilings.
- Uneven patches found on walls.
- Crumbly and wet plaster.
- Puddles and drips.
What are the Most Common Areas that Can be Affected by Penetrating Damp?
- Window Frames. These are inspected for the presence of cracks or gaps around the frame. These gaps and cracks will let the water come in and cause dampness.
- The Roof. Look for the tiles, roof ridges tiles, pointing and flashing. If any of them is loose or missing, maintenance is needed to prevent penetrating damp.
- External Walls. Look for pieces of mortar that are missing and the presence of cracks in the masonry. If they are observed, they can be repaired with the correct filling material to prevent penetrating damp.
- Door Frames. Look for cracks around the door frame and repair them if present. Look for the presence of a weather bar as well, as it helps in preventing penetrating damp. Install a weather bar if there is none.
- External rainwater downpipes, gutters and drains. Check them for cracks or leakage. Damage in the rainwater goods can be a source of penetrating damp.
How is Penetrating Damp Treated?
The most important thing to do is to get rid of the main source of moisture by inspecting every area in and around the building. Look for defects in the gutters, flashing, downpipes, window frames and rendering. Make sure that the gutter is free from obstruction, but if it is, consider replacing the guttering. If you find any gap around the window frame, you can seal it. You can also remove any debris in the cavity wall if you find any. The debris acts as a bridge for dampness from the outer wall to the inner wall of the property.
The waterproof coating could also be used on the external wall. The coating will form an impenetrable barrier against moisture and it will repel water as well. Fungal growth can also be prevented by the said coating.
For penetrating damp below ground, treatment is a little bit more complex. It is best if you hire a professional to do the job. An expert will apply a cementitious survey or plastic membrane in the masonry.
Seeking help from an expert will ensure that your damp problem is dealt with properly and professionally, resulting in the application of the right damp proofing treatment.
- If you notice any condensation build up around your home, dry it up. Damp and mould won’t thrive in dry areas.
- Proper air ventilation is key. You can simply open the window to let the moisture escaper from inside your home. You can have air vents installed as well.
- Keep cold surfaces in your home insulated because this is where condensation develops.
- Invest in a dehumidifier for your home. This will remove the moisture from the atmosphere, thus preventing the formation of damp in your home.
It is highly important to address the damp issue once it is detected no matter how minor it may seem. The real problems happen when the damp problem is allowed to spread and develop spores.
Constructing a wall with cavities may prevent moisture from penetrating into the building. If you are planning to renovate or build a new home, you should consider this as well. The cavity should be thoroughly ventilated.
If you require an appropriate and long-term solution for your rising damp problem, we at Southern Damp Proofing can provide you with exactly what you need. We have professional surveyors and damp proofing technicians to assist you at all times.
- Allow air to circulate around your home by opening the windows, which will promote air movement.
- Wet clothes, shoes and boots should be hung outside to dry, such as the utility room, garage and porch.
- Avoid putting furniture against outside walls so air can freely circulate.
- Radiators should be clear of obstructions such as furniture.
- Avoid overfilling wardrobes and cupboards.
- Do not block up a fireplace. You can install an air vent to promote ventilation.
Any form of dampness in your property can result in further damage. Whether you are noticing the development of rising or penetrating damp in your home, it is essential that you consult an expert. Our specialists here at Southern Damp Proofing will make sure that your damp problem is completely solved, so you can rest easy knowing that your property is damp free. Rest assured that we will respond to your request immediately. We give tips on how to maintain a damp-free property as well.