rising damp internal wall damage. Wall is showing flaking paint and bad defects

What causes rising damp on internal walls? Damp Patches

Welcome to the topic “What causes rising damp on internal walls?

Dealing with rising damp on internal walls in the UK

An average UK home has to deal with a massive amount of rain during the year. With that, it’s hardly surprising to see damp in the buildings. Unfortunately, many people won’t admit or understand that their property has a damp problem until the rising damp patches start showing clear signs on the internal walls.

Rising damp and penetrating damp both can affect your home’s internal walls. Penetrating dampness on inner walls occurs when water penetrates the building through cracks and openings in the walls, or it occurs due to any structural defect in the property. 

If you see damp patches on your walls rising from the ground level in an upward direction or you see any powdery deposits on walls, then these are the signs of rising damp.

Rising damp is a form of damp that damages the walls of the property in an upwards motion from the ground. When the water from the ground rises via the walls due to capillary action, rising damp occurs. The water that is sucked up also has salts that travel through the walls. It is noticed by the building’s damaged internal walls. The rising damp occurs mostly due to a broken or nonappearance of a damp-proof course in the building’s structure. If you reside in an apartment above the ground level, your property will not suffer from the rising damp problems because the damp rises from the ground level.

Sometimes, it can be difficult to identify the actual type of damp by just seeing damp on internal walls or crumbly plaster. Similarly, you cannot identify the main source of water ingress into the property in most cases. That’s why it is recommended to consult damp specialists or water ingress service providers to resolve and determine the cause of rising damp on internal walls.

rising damp internal wall damage
Rising damp on internal walls

What Causes Rising Damp in internal walls?

Most properties built in the UK have a barrier known as DPC (damp proof course) placed at the lower level preventing water to rise and damp patches on internal walls. A DPC is made of water-resistant non-absorbent materials like plastic, bitumen, and slate based at the time when the building was made. 

With time these DPCs might fail, whereas, in older buildings, they may not even exist. If your DPC has been damaged or if there is no DPC, then nothing can prevent water from travelling up your walls. 

Besides, your DPC might be bridged in the following ways:

  • Plaster directly connected to the solid floor at the bottom of the internal wall
  • Unsuitable insulation material in the wall cavity
  • Debris in the subfloor void or wall cavity
  • Solid floors
  • External ground levels being raised above the DPC

This problem is difficult to detect and resolve. Many people identify all damp issues as rising damp, but that’s not the case all time.

As stated above, rising dampness in buildings rises from the ground floor/level in an upward direction and then penetrates the brickworks of a wall via the capillary action. The most effective way is to implement the Damp Proof Course (DPC) to cure rising damp. The method is long-lasting and works well. DCP creates a waterproof barrier implanted into a house’s wall about five to six inches above the surface.

damp patches on internal walls causing bubbling paint above skirting board

What are the Common Signs of Rising Damp in your house?

If you are stressed about rising damp patches on the internal walls, there are some signs that you can look out for and find solutions to treat them. It includes:

  • Tide salts marks on walls or fluffy white deposits.
  • Black damp patches on walls with a mouldy smell. Black patches mean that the brickwork is actually wet from inside and not just the plaster.
  • Discoloured or crumbled plaster. You might also see cracking wallpaper and paint on the bottom side of the walls.
  • Musty smells are significant signs of damp.
  • Discolouration and black patches.
  • The weakening of mortar joints.
  • Damp wall
  • Damaged skirting board

Damp patches are not always noticeable on internal walls, and in some cases, your property can be affected by hidden damp. So, keep an eye on the following symptoms.

  • When you sense a mouldy/earthy odour in your place.
  • Your home suffers from regular condensation.
  • Your house feels humid.
black mould and signs of damp on internal walls of a house


How to Treat Rising Damp patches on Internal Walls?

Rising damp is a serious concern, and if left untreated, it leads to structural damages. In addition, it can destroy your flooring, plaster, and decorative finishes. It also accompanies the smell and makes it unpleasant to live in such an environment. 

However, you can treat rising damp on inner walls. It is advised that only damp professionals perform preventative tasks.

Improve the drainage system where your property is situated. Ensure that the nearby surface is sloping away from your home. Besides, also make sure that there is enough space for moisture to fade away from the ground.

Once correct damp course installations have taken place you can help prevent damp patches on internal walls by re-painting walls using mould-resistant paint. These paints create another damp-proofing barrier for walls that prevent dampness, condensation, and mould growth.

When you see signs of rising dampness on internal walls, it is better to remove wallpaper and plaster the bricks again. It is also advised to do the same on your property’s external walls.

Lastly, you must check that the DPC course has not been bridged before implementing a new damp proofing course. Treating rising damp on internal walls with an injection process works in most cases. Contact our damp proof treatment experts, they can carry out a damp survey for you and discuss all the possible options for remedial treatment of your internal damp patches.

damp proofing on exterior brickwork of house


How Effective Is A Chemical DPC?

As mentioned earlier in this read, chemical damp proofing or chemical injections are very useful to treat the rising damp problem on any property, provided they are installed correctly. They are effective methods of lining the pores of a masonry wall along with a water-repellent silicone resin. In modern times, many formulations are effective and provide a long-term solution for the said problem. Apart from DPC, you will also find various creams that provide and prevent rising damp issues.

Re-Plaster the Wall after Treating Rising Damp

After injecting the new DPC in your internal walls, it is always advised to plaster the affected wall or area. It is because your existing plasterwork may contain hygroscopic salts, and these salts can attract moisture. So, it is better to remove old plaster from the wall. 

You can hire a plasterer to re-plaster the wall to a precise specification. It will prevent problems arising due to salt contamination.


Who Treats Damp Problems in your home?

If you suspect or see symptoms of rising dampness on your property, then we will advise you to confirm your doubts with a damp specialist. In addition, you can seek help from a qualified and registered damp surveyor, rising damp treatment expert, or Preservation Company that deals with such issues.

In most cases, the surveyor carries out a rising damp survey in your home. Then, after detailed analysis, it recommends an action plan and appropriate damp proof treatment as per their findings.

If possible, check for the following qualifications when acquiring the services of any damp treatment expert of the company:

  • Certificated Surveyor in Remedial Treatments (CSRT) is a qualification for examiners and surveyors in the remedial home industry. The qualification includes three different modules, with one about dampness. 
  • Certificated Surveyor in Structural Waterproofing (CSSW) – It is a qualification for those involved in identifying issues with water penetrating the structures, and these recommend design solutions.

what causes rising damp on internal walls

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