Helpful Guides

A damp proof course is important in preventing damp around the home. This article will cover what it is and other common questions around them.

What is Damp Proof Course?

A damp proof course (DPC) is a barrier installed in the walls of a building to prevent moisture from rising from the ground into the walls.

It is usually placed above ground level (150mm) and can be made from materials like plastic, rubber, or metal. It is often seen within the brickwork in the lines of mortar as a bitumen or plastic DPC sheet slightly sticking out.

The DPC stops water from moving up through the building materials by capillary action, helping to keep the structure dry and prevent damage from dampness.

DPCs are required in all new construction to stop rising damp.

Types of Damp Proof Courses

There are generally 3 DPCs considered for a damp proofing project:

Damp Proof Course Injection

Also known as chemical damp proof course injections. It involves injecting water-repellent chemical or cream (usually silicone-based solution) into the walls.

Holes are drilled at least 150 mm above the external ground levels and the solution is injected into the walls.

As it is water repellent, it stops damp rising through the walls.

Mortar Injection Damp Proof Course

This method uses a chemically-enhanced mortar instead of creams or liquids.

The mortar is caulked into holes drilled into the wall. It is particularly useful in walls constructed of random rubble, which often have voids within their structure.

The mortar fills these voids once inserted. The chemical additives are absorbed from the mortar into the surrounding masonry and block rising damp.

Electro Osmotic Damp Proof Course

If chemicals are not suitable or if the property owner prefers a non-chemical solution, then an Electro Osmotic Damp Proof Course can be installed instead.

It works by using titanium and copper wiring to send a small electric current through the wall. This reverses the capillary action that causes rising damp and keeps it below the damp proof course.

How Do I Know If I Have a Damp Proof Course?

Damp proof courses are standard elements within a building construction.

They should be placed at least 150mm above the ground. They usually appear between layers of brickwork in the mortar course as a bitumen or plastic sheet poking.

They were introduced as a compulsory measure in 1875. The initial DPCs were made from materials like slate, lead, or engineering bricks.

However, these early barriers often failed due to improper installation or deterioration over time.

More effective materials like bitumen felt were used over time, and modern properties now typically use a plastic membrane DPC.

Why Do Damp Proof Courses Fail?

Most existing properties should feature a damp-proof course that is visible at least 150 mm above ground level. This is usually seen as a line of mortar with a bitumen or plastic DPC sheet protruding.

These materials are generally effective unless they are compromised in some way:

• Building movement that causes cracking: When a building settles or shifts over time, it can lead to cracks in the structure. These cracks can disrupt the continuity of the damp proof course (DPC), allowing moisture to bypass the barrier and enter the building.
• The DPC is bridged: Bridging occurs when soil, debris, or construction materials accidentally cover the DPC, connecting the damp ground to the wall above the DPC. This allows moisture to travel across the bridge and ascend past the intended barrier, leading to damp issues.
• The material degrades due to age: Over time, the materials used in damp proof courses, such as plastic, bitumen, or metal, can deteriorate. This degradation weakens their ability to resist moisture, making them less effective and eventually leading to failure.
• Building renovations raising ground level above existing damp proof course: If the ground level around a building is raised it can end up higher than the installed DPC. This means the DPC no longer serves as an effective barrier at the new soil level, allowing moisture to rise above the DPC and into the walls.

How to Install a Damp Proof Course

1. Prepare the Wall: Remove any damp plaster from the wall.
2. Drill Holes: Drill the holes at least 150mm above the ground level into the wall.
3. Install Damp-proof Course: Inject damp-proof cream into the holes, then seal them with mortar or plastic plugs.
4. Apply Scratch Coat: Put on a rough coat of plaster about 5mm thick to help the next layer adhere.
5. Apply Plaster Coat: Once the scratch coat has set, add a thicker plaster coat, between 15mm and 20mm.
6. Finishing Coat: Finish with a smooth skim coat of plaster.

How Long Does a Damp Proof Course Last?

The lifespan of a damp proof course can vary depending on the materials used, the quality of the installation, and the environmental conditions.

Generally, a well-installed and high-quality DPC can last for the lifetime of the building (up to 50 years).

However, chemical DPCs injected into the walls have a more variable lifespan. This is typically around 20 to 30 years.

Regular inspections and maintenance can help extend the effective life of any DPC.

Signs That You Need a Damp-Proof Course

Several clear indicators suggest the presence of damp in walls, including:

• Black spot mold on interior walls, which often also indicates condensation issues.
• Watermarks on walls, which can be caused by either rising damp or penetrating damp.
• Peeling plaster and damage to other wall finishes like wallpaper.
• Deterioration of wood, such as skirting boards, due to moisture contact.

What Next?

If you suspect damp issues in your property or notice signs of damp, it’s important to have a professional conduct a damp survey.

Without proper training, it can be challenging to accurately identify the source of the damp problem.

When left untreated, the damp will inevitably become more severe. This can eventually cause structural damage in due course and ultimately means higher repair costs in the long run.

This is why it’s recommended to get an experienced and certified specialist to visit your home as soon as possible.

Your property is in safe hands when you contact us.

Woodworm can be a big problem for things made of wood in your home, like furniture, floors, or even the beams that hold your house up.

If you’re worried about woodworm because you’ve seen signs of it, or just want to keep your wood safe, we’ve put together some easy-to-understand answers to the most common questions about woodworm. This should help you know more about what to do with woodworm in your home.

1. What is Woodworm?

Woodworm refers to the larvae of various wood-boring beetles, not worms.

While they pose no direct threat to human health, their presence can lead to significant damage in properties, as they consume wood upon hatching.

You know they’re there if you see tiny holes in the wood or a sort of dusty powder. They’re small but can damage wood over time.

Early detection of an infestation is crucial for effective treatment and to minimize potential damage to wooden structures.

2. Can Damp in My Home Cause Woodworm?

Damp conditions play a significant role in causing woodworm infestations.

This is because adult wood-boring beetles are more likely to lay eggs in damp wood. Damp timber is softer and easier for the larvae to chew through, making it an ideal environment for their development.

In dry conditions, the larvae might struggle to survive or the wood might be too hard for them to penetrate.

Wood that has been weakened by damp is more susceptible to infestation. It’s not just the softness of the wood that’s a factor; fungi and rot associated with dampness can also make the wood more appealing to beetles.

Essentially, damp wood creates an inviting habitat for wood-boring beetles to lay their eggs and for the larvae to feed and grow, thereby increasing the likelihood and severity of woodworm infestations.

That’s why managing humidity and preventing dampness are key to preventing woodworm problems.

3. How Does Woodworm Spread?

Woodworm spreads mainly through adult beetles laying eggs on or in wooden surfaces. Here’s how it typically happens:

1. The adult beetles, having matured from the larvae, leave the wood they were in and look for mates.
2. After mating, the female beetle lays her eggs in cracks, crevices, or existing tunnels in wood. This can be in the same piece of wood they emerged from or in new wooden items.
3. The eggs hatch into larvae, which are the actual woodworms. These larvae then burrow into the wood, eating and creating tunnels as they grow.
4. If infested furniture or timber is moved to a new location, the woodworm can spread to other wooden items or structures in that area.
5. Once they reach maturity, the larvae transform into adult beetles, emerge from the wood, and the cycle begins again.

4. How Big Are Woodworms?

Woodworms, which are actually the larvae of wood-boring beetles, vary in size depending on the species.

However, they are generally quite small, with most woodworm larvae being about about 1mm to 7mm long.

For example, larvae of the Common Furniture Beetle, one of the most typical wood-boring beetles found in the UK, grow to about 3mm to 5mm in length.

Remember, their small size can make them difficult to spot with the naked eye, especially when they’re newly hatched. The more visible signs of woodworm presence are the small holes they leave in wood and the powdery frass around these holes.

5. What Do Woodworms Look Like?

Woodworm, in its larval stage, typically has a distinctive appearance.

They are elongated and cylindrical, resembling a small worm or maggot and the color of woodworm larvae ranges from white to a creamy or light brown shade.

As mentioned previously, they are quite small, generally around 1mm to 7mm in length, depending on the species and age.

Woodworm larvae have a curved body and may appear slightly segmented. They also have a well-defined head, which is often darker than the rest of their body.

6. How Quickly Does Woodworm Spread?

The spread of woodworm, or the rate at which wood-boring beetle larvae infest wood, can vary based on several factors. It’s not an overnight process; it can take years, depending on a variety of conditions such as:

1. Species of Beetle: Different species have different life cycles. For example, the Common Furniture Beetle has a life cycle that can range from one year to several years.
2. Wood Type and Condition: Softer, damp wood is more susceptible to infestation and allows for quicker spread and growth of the larvae.
3. Environmental Conditions: Higher humidity and warmer temperatures generally accelerate the life cycle of the beetles, leading to faster reproduction and spread.
4. Introduction of Infested Wood: Bringing in new pieces of infested furniture or timber can quickly introduce woodworm to previously uninfested areas.
5. Detection and Treatment: Early detection and treatment can significantly slow down or halt the spread. Untreated infestations can gradually worsen over several years.

7. Can Woodworm Fly?

When we talk about woodworm, it’s actually the larval stage of wood-boring beetles that cause the damage. These larvae, which we refer to as woodworm, live inside the wood, eating and tunneling through it. They don’t have the ability to fly.

However, once they mature and emerge from the wood as adult beetles, they do have wings and can fly. This is an important part of their life cycle because it allows them to spread to new areas and find new sources of wood to lay their eggs.

So, while the woodworm itself can’t fly, the adult beetles they turn into certainly can. This flying ability is how they move from one wooden item to another, potentially spreading the infestation.

8. Where are Woodworms Commonly Found?

Woodworms, or the larvae of wood-boring beetles, are commonly found in various places around the home, especially where there is timber or wooden items. Some of their favorite spots include:

• Attics and Lofts: These areas often contain untreated timber in the form of roof trusses and beams, which can be appealing to woodworm.
• Basements and Cellars: The damp conditions often found in these areas make them ideal for woodworm, especially in older homes.
• Floorboards: Particularly in older houses, wooden floorboards can be susceptible to woodworm infestation.
• Furniture: Wooden furniture, especially antiques and second-hand items, can harbor woodworm.
• Skirting Boards and Door Frames: These areas can be affected, especially if the wood is untreated or the property is older.
• Wooden Beams and Panelling: Exposed beams and wood panelling are common in historic or period properties and are attractive to woodworm.
• Stored Wooden Items: Like old picture frames, wooden crates, or even musical instruments stored in attics, basements, or other less frequented areas of the home.

Regular inspections of these areas, particularly in older homes or in damp conditions, can help in early identification and treatment of woodworm infestations.

9. Is Woodworm a Serious Problem?

Yes, woodworm can be a serious problem, especially if left untreated. While individual woodworms are small and might seem insignificant, their collective impact over time can be substantial.

This is because over time, the tunneling activity of woodworm larvae can weaken the structural integrity of wooden beams, floorboards, and other elements of a building. This can lead to costly repairs and, in severe cases, structural failure.

If not addressed, woodworm can spread to other wooden items in the home, leading to more extensive damage.

The longer an infestation is left untreated, the more extensive and costly the treatment can be. This is why it’s essential to get a woodworm infestation expert to diagnose and treat the problem as early as possible.

Speak to a Woodworm Infestation Expert

For widespread infestations or those involving destructive species, it’s essential to have woodworm treatment conducted by experienced contractors.

To locate woodworm treatment companies near you, feel free to reach out using the form below.

When considering whether to get a free damp survey for your property in the UK, there are several factors to weigh.

This article explores the importance of damp surveys, the benefits and potential drawbacks of free assessments, and how to make an informed decision.

Understanding Damp Surveys

A damp survey involves a detailed inspection of a property by a professional to identify issues related to moisture. T

his includes rising damp, penetrating damp, and condensation problems. The surveyor assesses the extent of dampness, identifies the causes, and recommends appropriate remedial actions.

Why Consider a Free Damp Survey?

1. Cost-Effective Initial Assessment: Free surveys offer a cost-effective way to initially assess the damp issues in your property. For homeowners on a budget, this can be a great starting point
2. Identify Potential Problems Early: Early identification of damp can prevent more significant and costly damage in the long run. A free survey can act as a preliminary step in maintaining the structural integrity of your property.
3. Expert Advice: Professionals conducting these surveys have the expertise to identify damp-related problems that might not be obvious to the untrained eye.

Potential Drawbacks of Free Damp Surveys

1. Quality and Depth of Assessment: There’s a concern that free surveys may not be as thorough as paid ones. Some companies might offer a basic overview rather than a detailed investigation.
2. Upselling Services: Firms usually offer free surveys with the intention of selling their damp proofing services. It’s important to ensure that the advice given is impartial and not just a sales tactic.
3. Limited Scope: A free survey might cover basic aspects of damp proofing but might not delve into underlying issues that could be more complex and require specialized attention.

Independent Surveys vs Free Surveys

If you plan to sell your home, you will need a full survey report from an independent, qualified surveyor. A free survey will be ignored by mortgage lenders.

If you simply want a second opinion on a damp issue within your home, then a free damp survey can be a good choice.

However, remember there is an incentive to be biased so that they can sell their damp proofing services. Be sure to ask lots of questions and get multiple contractor quotes and opinions so that you don’t end up paying for something you don’t need.

To Sum Up

A free survey can be a good choice if you don’t want to spend money getting an initial assessment whilst getting a damp specialist to look at your problem.

A damp expert can identify problems early in a cost-effective manner.

However, be wary that many contractors will be far more biased to then sell their services compared to an independent survey.