Damp Bricks

Damp Bricks At The Bottom Of The House

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Key Takeaways:

  • Proximity to Foundation Heightens Concern: Damp bricks at the bottom of a house, especially near the foundation, pose a significant threat. Beyond aesthetic concerns, this issue can weaken the base, leading to structural problems and potential health hazards like black mould growth, impacting both the stability and value of the property.
  • Root Causes of Damp Bricks: Poor drainage systems, groundwater seepage, capillary action, and faulty damp-proof courses contribute to damp bricks. Incorrectly designed drainage can lead to water accumulation around the foundation, while groundwater seepage weakens the brickwork.
  • Visual and Structural Indicators: Staining, discolouration, efflorescence, and structural weakening are visual indicators of damp bricks. Stains and dark patches on walls, along with efflorescence, reveal moisture interaction with the masonry.

In this article, we will explore the reasons behind the existence and the havoc that damp bricks at the bottom of your house can wreak. We’ll cover causes, identify indicators, and determine how to fix the underlying problem. Interested? Let’s jump right in!

What is Damp and Damp Brickwork?

In this particular context, we refer to dampness in conjunction with construction. That refers to moisture’s unwanted (and unneeded) presence within the building structure.

Indeed, it’s a pretty pervasive issue that manifests itself in walls, floors, and foundations through forms like rising dampness, penetrating dampness, condensation, and even wet rot on damp exterior walls or interior sections.

The sources of this problem can be due to external factors – rainfall or groundwater – or internal ones like plumbing leaks. But all that accumulates in moisture infiltration, leading to a wet brick problem under your house.

Different Types of Damp

In more detail concerning the previous mentions, let’s consider the different types of damp issues that ‘penetrate’ the building:

penetrating damp affecting bricks

Damp at the Bottom of a House

Damp at this location is particularly concerning due to its proximity to the foundation. While damp anywhere can lead to many problems, this affected area impacts other areas.

Not only does this problem affect the house at the ground level, but it also leads to weakened bases and structural issues in the long run, making the base unstable and vulnerable to further problems like health hazards (such as black mould growth) or property value issues (in terms of aesthetics, etc.).

Learn more about structural damp here.

What Causes Damp Bricks at the Bottom of the House?

1: Poor Drainage Systems

Drainage is an essential part of protecting a house – especially the foundation – from penetrating damp. If not installed correctly, water from heavy rain and other sources accumulates around the house (around its foundation), creating a moisture-laden environment which allows mould to take root.

Additionally, the stagnant water infiltrates the porous materials of the external and internal walls, leading to a penetrating damp buildup.

Therefore, a properly designed gutter system and downspouts are vital in helping the water escape from the pooling areas around the structure and helping prevent water from rising damp.

flooding and damp around bricks

2: Groundwater Seepage

A correct diagnosis of this issue can lead to an easy fix by dealing directly with the surrounding issue, so learning what it entails is necessary. Groundwater seepage, in simple words, happens when water from the surrounding soil permeates the foundation.

This generally happens in regions with high water tables, heavy rain, or even frost damage. If you’ve recently noticed any of these problems, remember to check for the foundation of your house so you know if you have a problem.

Also note that if you don’t keep an eye out, the consistent exposure to groundwater will compromise the mortar and brickwork that makes up your house’s foundation. It dissolves the minerals and weakens the bond from brick to brick, leading to an overall deterioration of building materials.

3: Capillary Action

Water moving through the small spaces within porous materials is called “Capillary Action”.

In this particular scenario, this action through each brick happens due to the adhesive and cohesive forces between water molecules and the material. It draws moisture up from the ground into the lower sections of a building.

That, in turn, becomes one of the main causes of the penetrating damp in the house.

However, specifically for brickwork, capillary action leads to visible signs of damp and mould. Additional outcomes – especially over the long term, while the capillary action is left unchecked – include:

  • Staining
  • Efflorescence (white, powdery deposits)
  • Structural weakening
capillary action in brickwork in action

4: Faulty Damp Proof Course (DPC)

Role of DPC in Preventing Damp

The damp proof course is a damp treatment installed to prevent rising damp. It typically includes a layer of water-resistant material like bitumen or plastic, which is incorporated into the lower part of the walls.

If the damp proof course fails (poor installation or deterioration), it gives space for moisture to rise (see capillary action above).

Identifying Damp Bricks

Visual Indicators

Staining and discolouration are obvious symptoms of penetrating damp, indicating damp bricks.

When the water causes the minerals in every other brick to dissolve, it leads to unsightly marks of off-colours on the surface and walls, which means dark patches or streaks on the lower sections of internal walls and the other symptoms on the lower sections of external walls.

On the other hand, efflorescence refers to the powdery crystalline deposit that appears on the surface of a brick when water evaporates and leaves behind salts. This white substance means that moisture is interacting with the masonry.

Structural Signs

Damp conditions can compromise the integrity of the mortar between bricks. Over time, the mortar may weaken, crumble, or develop a sandy texture. Inspecting the mortar joints for signs of deterioration is essential in assessing the extent of the dampness.

Damp environments grow mould and fungus. If left unchecked, these organisms can proliferate on damp bricks, contributing to both aesthetic and health-related concerns. Black or green patches on the walls indicate mould growth and should be addressed promptly.

structural issues with damp in building

How to Treat Damp Bricks?

Preventive Measures

Proper Site Grading

a: Importance of Sloping Away from Houses

When your house is being built, ensure that the ground slopes away from the house so there is little chance of water accumulation near the foundation and the base of the exterior walls.

This will minimise the chance of penetrating damp from wind driven rain, which will naturally be diverted to lower ground.

sloping house to prevent water accumulation

b: Landscaping to Improve Drainage

Additionally to the sloping technique, landscaping strategically allows you to enhance drainage, such as grading or using absorbent plants, which improve the visual appearance and act as preventative measures to rising damp.

Moreover, creating channels like weep holes (small openings that allow water to drain from a building envelope) helps water flow away and incorporate into well-draining soil.

Adequate Ventilation

a: Role of Ventilation in Preventing Dampness

Proper ventilation helps reduce the humidity within your property. Adequate airflow prevents moisture buildup on interior and exterior walls and minimises the likelihood of damp accumulation.

While well-ventilated spaces can lead to increased heat loss in the short run, they facilitate the natural evaporation of any accumulated moisture, leading to more long-term structural strength and insulation of a house.

b: Installation of an Air Brick

Air bricks allow for ventilation in subfloor spaces. Installing them strategically allows the circulation of air beneath the house, helping keep the structure dry and preventing the dampness from affecting the lower sections of the internal walls.

c: Reconsidering Cavity Walls

If your house has cavity wall insulation (or you’re thinking about it), remember that this technique helps trap moist air between the exterior and interior walls.

In this way, the cavity wall insulation may keep your house warm, but this can be a precursor to damp since the moist water vapour will linger.

Repairing Drainage Systems

Clearing Gutters and Downspouts

If you have gutters and downspouts (again, necessary for drainage), you must maintain them. That means regular checks and balances so that no obstruction of waterways leads to pooling water penetrating the brickwork.

Installing French Drains

An additional drainage option is installing french drains, which effectively redirect groundwater. This includes installing a perforated pipe surrounded by gravel, which allows excess water to be channelled away from the building.

drainage, french drain

Waterproofing Techniques

External Waterproofing

a: Application of Waterproof Membranes

Waterproofing bricks coating, and membranes, can create a protective barrier against moisture, so their application to exterior walls is effective in regions with heavy rainfall and high groundwater levels.

b: Importance of Quality Sealants

Sealants, especially high-quality ones, are incredibly useful in fortifying building structures when applied to more vulnerable areas like windows, frames, and joints. However, you must remember to inspect regularly and, if necessary, reapply.

high quality sealants to stop damp

Internal Waterproofing

a: Tanking Solutions

Tanking is a structural waterproofing technique for internal walls, which creates a barrier using a membrane similar to that used for exterior walls. This is generally utilised for basements and similar areas, which are more prone to water infiltration and, thus, to dampness.

b: Waterproofing Paints and Coatings

Other than membranes, things like waterproof paint and coatings can also be applied to internal surfaces. These create a protective layer to prevent rising damp from affecting the bricks while providing a visually appealing finish at the same time.

waterproofing and paint and coatings

Restoration of Damp Bricks

Removal and Replacement of Affected Bricks

When the penetrating damp has already affected specific bricks in the foundation of your house, it may be too late for the bricks themselves.

But worry not – there’s an answer. You can remove and replace them, eliminating the source of the rising damp and ensuring the structure and integrity of the walls.

Repointing and Re-rendering

A second method of restoration includes reporting and re-rendering.

  • Repointing refers to replacing deteriorated mortar with a fresh mixture, strengthening the bond between bricks.
  • Re-rendering includes applying a new layer of render.

Both, however, offer an additional barrier against the penetrating damp.

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When you look into the problem of damp bricks at the bottom of a house, you realise it’s not just about aesthetics – it’s also about ensuring a home’s structural integrity and health.

Thus, prevention and early detection are the answer because long-term exposure leads to many consequences. These include a compromised load-bearing capacity and health hazards.

Preventative measures include proper property drainage, ventilation, and quality waterproofing, which can also help avoid over-expensive repairs. However, if repairs are necessary, you can replace the brickwork or re-render and repoint.

Regardless, in short, by understanding causes, effects, and ways to treat this issue, you can safeguard your property against the pervasive threat of this rising damp, ensuring a resilient and enduring living space.

Picture of Jake Fitzgerald - Damp Surveyor

Jake Fitzgerald - Damp Surveyor

Surveyor of Timber & Dampness in Buildings (CSTDB) & ( MRICS ) Chartered Quantity Surveyor

Jake is a qualified chartered quantity surveyor and experienced damp specialist with a unique skill set in thermal imaging. With a focus on effective solutions, Jake combines his expertise in quantity surveying and thermal imaging to accurately assess and address damp-related issues. He utilises advanced technology to identify hidden moisture sources and develop targeted strategies, ensuring comprehensive and cost-effective solutions for his clients. With a commitment to open communication and client satisfaction, Jake delivers cutting-edge solutions that tackle damp challenges head-on.

Connect with him on Linkedin...

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