Damp Proofing in Reading: Common Causes and the Right Treatment

Damp can affect properties of almost any age, and the correct treatment depends entirely on what is causing the moisture.

If you are looking for damp proofing in Reading, the first step should not automatically be installing a new damp proof course or applying a waterproof coating. Damp patches, mould, peeling paint and damaged plaster can have several different causes, and treating the wrong one can result in the problem returning.

Shield provides professional damp proofing in Reading, including surveys to identify the source of moisture and recommend the most appropriate treatment for the property.

What Causes Damp in Reading Homes?

There is no single cause of damp.

Properties can develop moisture problems because of defects in the building, plumbing leaks, condensation, inadequate ventilation or problems with the damp proof course.

Common causes include:

• Penetrating rainwater
• Defective gutters and downpipes
• Damaged pointing or render
• Leaking roofs
• Plumbing leaks
• Failed seals around windows and doors
• High external ground levels
• Bridged or defective damp proof courses
• Condensation and poor ventilation
• Damp beneath suspended timber floors
• Defects within cavity walls
• Previous damp treatments that have failed

Sometimes more than one problem is present.

This is why accurate diagnosis is so important before any remedial work begins. Our guide explaining why damp diagnosis matters looks at this in more detail.

What Are the Common Signs of Damp?

Some damp problems are obvious, while others develop gradually.

Warning signs can include:

• Damp patches on walls
• Peeling paint or wallpaper
• Crumbling plaster
• White salt deposits
• Dark staining
• Black mould
• Musty smells
• Rotting skirting boards
• Damp around windows
• Water staining after heavy rain
• Cold or persistently damp walls
• Decaying floorboards or joists

Where these symptoms appear can provide useful clues.

For example, damp concentrated around a window or chimney may have a different cause from moisture appearing consistently at the bottom of a ground-floor wall.

Is It Rising Damp?

Rising damp is one possible cause of moisture at low level, but it should not automatically be blamed whenever damp appears near the floor.

True rising damp occurs when groundwater moves upwards through porous masonry.

A functioning damp proof course is intended to prevent this moisture from continuing upwards.

Problems may arise where:

• The original damp proof course has deteriorated
• No effective DPC is present
• External ground levels are too high
• Render, plaster or debris bridges the damp proof course
• Previous alterations have compromised the original protection

However, similar-looking symptoms can also be produced by penetrating moisture, plumbing leaks or condensation.

This is why simply injecting a new chemical damp proof course without establishing the cause may not solve the problem.

You can read more about the wider subject in our complete guide to damp proofing.

Could It Be Penetrating Damp?

Penetrating damp occurs when moisture passes into the building from outside or from a localised defect.

Unlike rising damp, it is not restricted to the lower part of a wall.

Common causes include:

• Cracked masonry
• Defective pointing
• Damaged render
• Leaking gutters
• Overflowing downpipes
• Roof defects
• Poor seals around windows
• Defective flashings

One clue can be damp that becomes noticeably worse during or after rainfall.

The affected area may also be relatively localised and correspond with an external defect.

Repairing the source of water ingress is normally the priority rather than treating the internal wall alone.

Our guide to penetrating damp causes and treatment explains some of the most common problems.

Condensation Can Look Like Damp Proofing Failure

Not every damp wall requires damp proofing.

Condensation can cause:

• Black mould
• Damp corners
• Moisture around windows
• Mould behind furniture
• Peeling decorations
• Musty smells

It occurs when moisture in the air meets a sufficiently cold surface and condenses into water.

Bathrooms, kitchens, bedrooms and poorly ventilated rooms can be particularly vulnerable.

Possible contributing factors include:

• Inadequate extractor fans
• Poor airflow
• Cold external walls
• High indoor humidity
• Drying clothes indoors
• Insufficient heating
• Furniture positioned tightly against external walls

Installing a damp proof course will not solve a condensation problem.

Ventilation, heating, insulation and moisture management may need to be considered instead.

If you are unsure which problem you have, our guide to condensation versus rising damp explains some of the differences.

Damp Around Windows

Damp around windows is another common problem that can easily be misdiagnosed.

Possible causes include:

• Failed external sealant
• Defective pointing
• Cracks around the opening
• Leaking guttering above
• Condensation on cold reveals
• Poor insulation around the window
• Defective cavity detailing

If mould appears mainly in the corners or reveals during colder weather, condensation may be involved.

If staining becomes worse after rain, external water penetration should be investigated.

Read our guide to damp around windows and its possible causes for further information.

What Happens During a Damp Survey?

A professional damp survey should consider the entire area affected rather than simply taking a moisture-meter reading and recommending treatment.

Depending on the property and symptoms, the surveyor may inspect:

• Internal wall surfaces
• Moisture patterns
• Skirting boards and timber
• Floor construction
• Ventilation
• External ground levels
• Pointing and render
• Gutters and downpipes
• Roof defects
• Windows and doors
• Plumbing
• Existing damp proofing
• Previous repairs

Moisture readings may form part of the investigation but should be interpreted alongside the construction of the property and the other evidence available.

The objective is to identify the most likely source of the moisture before recommending remedial work.

Our article explaining what a damp survey involves provides more information about the inspection process.

If you are concerned about moisture in your property, find out more about Shield’s free damp survey and what the inspection can help identify.

What Damp Proofing Treatment Might Be Recommended?

The correct treatment depends on the survey findings.

There is no single damp-proofing system suitable for every property.

Chemical Damp Proof Course

Where genuine rising damp is identified and the original DPC is missing or ineffective, a chemical damp proof course may be appropriate.

The treatment involves introducing a specialist damp-proofing material into the masonry to create a barrier against rising moisture.

Replacement Plaster

Where walls have been affected by moisture and salts, damaged plaster may need to be removed and replaced with a suitable specification.

Simply redecorating over contaminated plaster may allow staining to return.

Repairs to External Defects

Where penetrating damp is involved, treatment may include repairs to:

• Pointing
• Render
• Gutters
• Downpipes
• Roof coverings
• Flashings
• Window surrounds

In these situations, stopping the water entering the building is the priority.

Ventilation Improvements

Where condensation is contributing to the problem, recommendations may include improved extraction, increased airflow or other ventilation measures.

Floor and Timber Repairs

Damp beneath floors can sometimes affect joists and floorboards.

Where timber decay is suspected, further investigation may be needed to determine whether wet rot, dry rot or wood-boring insects are present.

Why the Cause Must Be Treated First

Covering a damp wall with new plaster, paint or wallpaper may improve its appearance temporarily, but it will not solve an active moisture problem.

Similarly, installing a chemical DPC will not repair:

• A leaking gutter
• A plumbing leak
• Defective pointing
• Condensation
• A roof defect
• Water entering around a window

The most effective remedial work begins by establishing where the moisture is coming from.

Only after that has been established should the appropriate treatment be specified.

What If Damp Comes Back After Treatment?

Recurring damp can indicate that the original cause was not fully resolved or that another moisture source is present.

Possible reasons include:

• Incorrect initial diagnosis
• Continued external water penetration
• A hidden plumbing leak
• Inadequate ventilation
• Bridging of the damp proof course
• Contaminated plaster
• Insufficient drying time
• More than one damp mechanism affecting the area

If previous damp treatment has failed, it is worth arranging a fresh inspection rather than automatically repeating the same work.

Our article on why damp comes back after treatment explains some of the reasons this can happen.

Should You Repair Damp Yourself?

Minor maintenance such as clearing a blocked gutter or improving ventilation may sometimes help with straightforward moisture problems.

However, specialist investigation is advisable where:

• Damp repeatedly returns
• Large areas are affected
• Plaster is deteriorating
• Timber is decaying
• Mould is extensive
• There is no obvious source of moisture
• Previous treatment has failed
• You are considering installing a new damp proof course

Treating the symptoms without identifying the cause can make the eventual repair more expensive.

Damp Proofing Surveys in Reading

Shield Waterproofing & Preservation provides professional damp surveys and damp-proofing services throughout Reading and the surrounding area.

Our experienced surveyors investigate the likely cause of the moisture before recommending suitable remedial work.

Depending on the findings, this may include:

• Damp proof course installation
• Damp-proofing treatments
• Repairs to damaged plaster
• Penetrating damp repairs
• Ventilation recommendations
• Timber investigations
• Structural repairs
• Further specialist investigation where required

The aim is to recommend the work the property actually needs rather than applying the same treatment to every damp problem.

Book a Damp Survey in Reading

If you have noticed damp patches, mould, peeling paint, damaged plaster or persistent musty smells, arrange an inspection before the problem becomes more extensive.

A professional survey can help determine whether the cause is rising damp, penetrating damp, condensation, a building defect or another source of moisture.

Contact Shield Waterproofing & Preservation today to arrange a damp survey in Reading and receive clear recommendations for the appropriate next steps.