Chemical damp proof treatment
How Effective are Chemical Damp Proof Treatments?
Damp is a common issue in UK homes due to the amount of wet weather that we get throughout the year. This is especially true if you live in an older home where the risk of damp is even higher due to the lack of damp-proofing treatments compared to newer homes in the country today. There are several different types of damp that can impact your home including penetrating damp, which involves moisture from the outside making its way to the inside walls of your home, rising damp, which occurs when the damp proof course is not working effectively and water reaches the foundations, and condensation damp, which is caused by a build-up of warm air inside the home that settles and condensates on the cold wall surfaces. If you want to treat or prevent rising damp inside your home, you may be considering the option of a chemical damp proof course. But how effective is chemical damp proofing, and is it a good solution for your home?
What is the Damp Proof Course?
A damp proof course is an important feature for any property. The purpose of the damp proof course is to provide a waterproof feature just about the outside ground level of your property. The aim of this is to prevent moisture from rising from the ground and into your property. It’s normally placed at around 150mm above the outside ground level, which is typically at the mortar joint above the second course of bricks.
Placing a damp proof course in new properties was first made mandatory in London in the 1870s before it quickly became a regulation for all new build properties in the country. In the late 1800s and early 1900s, the most common materials used for a damp proof course were typically less porous building materials like slate. Later on, other materials such as bitumen would be used. More recently, new build properties in the UK tend to be installed with a plastic damp proof course, which is usually made of low-density polyethylene. The most recent type of damp proof course to enter the market is a chemical damp proof course, which is not designed to be used during the construction period but is rather one of the best ways to replace or repair an old damp proof course that is no longer working effectively.
Is Chemical Damp Proof Treatment a Good Idea?
If you need to replace or add a new damp proof course to an existing home, a chemical damp proofing treatment can be an ideal option since it is often much easier to install compared to alternatives. This is because the chemical damp proof course is simply injected into the mortar through drilled holes, allowing you to avoid the major structural work to the property that will often be a part of replacing the original damp proof course.
Does It Work?
When installed correctly, chemical damp proof courses can be a very effective option. The damp proof course will be injected into the mortar bed at 100-150mm intervals. The chemical damp proofing treatment is made from silicone, which creates a completely waterproof barrier by filling the pours in the mortar. Once complete, it should create and provide an effective damp proof course that can be expected to last around two decades. In fact, most companies and professionals that install this type of damp proof course will usually offer a guarantee of twenty years since they are confident that the damp proof course will not fail before the end of this period.
When to Use a Damp Proof Chemical Treatment?
A chemical damp proof course will often be installed after rising damp has been discovered in a property. Rising damp is often a sign of a damp proof course that has failed or has been bridged. While the cause of the bridge can be removed and will usually prevent further damp if there are no other issues, a damp proof course that consistently becomes bridged, or if the damp problem persists after the bridge has been removed, this will usually require a damp proof course replacement.
Rising damp is a problem that is usually visible near the ground level of the property, above the skirting boards up to around 1.2m up the wall. At this point, the rising damp will usually stop since the gravity will stop it from climbing up the wall any further. Rising damp often appears like tide marks on the wall, and there may be a white residue present on the internal walls due to hygroscopic salts that have been drawn from the ground and the brickwork.
If you have noticed these issues in your home, there’s a high chance that you could be dealing with a rising damp problem. However, it’s also worth noting that rising damp is often one of the most commonly misdiagnosed types of damp, so it’s worth having your property checked by a damp specialist before taking action to make sure that you have ruled out any other potential causes.
Common Misdiagnoses:
The most common misdiagnoses is usually for penetrating damp or cavity bridging. You will need to have a damp inspection carried out on your property to rule out penetrating damp as a cause. The main aim of this is to try and identify the potential causes for the damp that is appearing internally in your home. It’s also a good idea to examine the outside wall adjacent to the inside damp to look for any obvious defects or damage to the exterior walls. This could include damage, wear, or tear to the bricks and the mortar. You should also look for any signs of damage to the existing render which will be applied to the outside of the property. Look around and above the area to see if there are any defects in the wall that could be allowing water to enter and move down the internal cavity wall. If this is the case, it could then be bridging across and into the property at the areas where the damp is present. If you can rule out these issues, it’s likely that your damp proof course has failed and is in need of replacement.
Does a Chemical DPC Work for Penetrating Damp?
If you have ruled out rising damp and found external defects in the wall, you’ll still need to make sure that the problem is dealt with in order to prevent penetrating damp issues. However, a chemical damp proof course will not be effective in preventing penetrating damp in your home. This is because penetrating damp is more likely to occur above the damp proof course. If it occurs below the damp proof course, it’s likely to be due to a problem with the damp proof course that allows the damp to rise. In this case, you may benefit from replacing your DPC with a chemical alternative while still repairing the external defects that have led to penetrating damp. But for the most part, a chemical damp proof course is designed to deal with rising damp – you will need to consider other solutions if rising damp is not the issue in your home.
Can You Install a Chemical Damp Proof Course Yourself?
You might be wondering if it’s worth having your chemical damp proofing course installed by a professional or whether you can opt for DIY. The truth is that both options can work very well, since the process is actually quite simple, involving drilling holes and injecting the chemical formula into the mortar. You can get DIY kits that come with complete instructions making them a relatively straightforward option to use for people who enjoy DIY.
However, if you feel less confident doing the job yourself or don’t have the tools that will be required to do it effectively, you may want to consider hiring a professional. It’s worth getting quotes from several different local companies and comparing the price, along with comparing the price of doing it yourself. In the case where the overall cost is not very different from getting a DIY kit and the necessary tools to do the job, you might find that you are better off hiring a professional to do the work for you since you can be sure of a quality job. Another benefit of working with a professional when having a chemical damp proof course installed is that most professional companies will guarantee the work, so you can rely on them to come out and fix it if you have an issue. Many will guarantee the job for up to two decades, giving you plenty of time with complete peace of mind. Both hiring a professional and going the DIY route are viable options to consider, and will ultimately depend on your situation, budget, and your level of DIY experience.
Chemical damp proofing is an ideal option to consider if you need to repair or replace your home’s damp proof course. If you are experiencing rising damp, chemical damp proofing is simple to install and involves less hassle compared to alternative methods.
Equipment Used During Our Surveys
Equipment Used During Our Surveys
Purpose:
Takes comparative moisture readings from walls, ceilings, floors and timber to identify abnormal moisture patterns.
Common Uses / Notes:
Used when investigating rising damp, penetrating damp, condensation and leaks. Readings support the survey but are not a diagnosis on their own.
Subsurface Moisture Meter
Purpose:
Detects moisture beneath the surface of suitable building materials.
Common Uses / Notes:
Helps determine whether moisture is confined to surface finishes or extends into the building fabric.
Non-Damaging Moisture Scanner
Purpose:
Scans surfaces for hidden moisture without causing damage.
Common Uses / Notes:
Ideal for decorated walls, ceilings and flooring where pin testing would be undesirable.
High-Resolution Borescope Camera
Purpose:
Inspects hidden or difficult-to-access areas without opening up large sections of the building.
Common Uses / Notes:
Used beneath floors, inside cavities, behind walls and around pipework to identify damp, leaks, decay and concealed defects.
4K Aerial Inspection Drone
Purpose:
Captures high-resolution images of roofs and other inaccessible external areas.
Common Uses / Notes:
Inspects roof coverings, chimneys, flashing, gutters, valleys, parapets and high-level masonry. Subject to weather, safety requirements and flight regulations.
Atmospheric Humidity Sensor
Purpose:
Measures indoor relative humidity levels.
Common Uses / Notes:
Helps assess condensation and mould risk alongside temperature, ventilation, heating patterns and room usage.
Gas Detection Monitor
Purpose:
Screens for certain airborne gases where unusual odours are present.
Common Uses / Notes:
May detect gases associated with drainage, combustion or flammable substances. Does not replace inspection by a Gas Safe registered engineer where gas appliances or pipework are involved.
Thermal Imaging System
Purpose:
Identifies temperature differences across building surfaces.
Common Uses / Notes:
Helps locate cold spots, thermal bridging, insulation defects and areas associated with concealed moisture. Results always require further investigation to confirm the cause.
Basic Socket and RCD Tester
Purpose:
Performs limited electrical checks during comprehensive surveys.
Common Uses / Notes:
Can identify basic socket wiring issues, AC voltage and RCD operation. It is not an Electrical Installation Condition Report (EICR).
Chemical Vapour Testing Device
Purpose:
Screens for airborne volatile organic compounds (VOCs) and formaldehyde.
Common Uses / Notes:
Used where chemical odours, emissions from materials or indoor air-quality concerns are suspected after leaks or refurbishment.
Fine Air Particle Counter
Purpose:
Measures airborne particulate matter (PM1.0, PM2.5 and PM10)
Common Uses / Notes:
Assists with investigations involving dust, smoke, mould concerns, post-construction contamination and indoor air quality following water damage.
Extraction and Air-Movement Tester
Purpose:
Measures the performance of extractor fans and mechanical ventilation systems.
Common Uses / Notes:
Used in kitchens, bathrooms and utility rooms to identify poor ventilation that may contribute to condensation and mould growth.
Survey Levels and Equipment Provided
Basic Moisture Survey
Standard price: £299 + VAT
Special offer: £199 + VAT until the end of this month
The Level 1 survey provides a basic assessment of the main accessible internal surfaces. It is most appropriate for simple, localised damp concerns where advanced testing is not required.
Equipment Included
- Professional damp meter
Survey Checks
- Accessible walls
- Accessible floors
- Ceilings
- Visible plumbing and drainage leak inspection
- Damp-control and prevention information
Suitable For
This survey is suitable for a customer who has found an isolated damp patch, suspects rising damp in a limited area or wants a straightforward check of the property’s accessible surfaces.
Only a standard damp meter is included. Customers requiring deep moisture detection, timber inspection, thermal imaging or roof inspection should select a higher survey level.
The survey fee will be deducted if we carry out the recommended work.
Damp, Moisture and Timber Survey
Standard price: £399 + VAT
Special offer: £299 + VAT until the end of this month
Level 2 includes everything in the Level 1 inspection and adds deeper moisture detection, non-invasive scanning and timber assessment.
Equipment Included
- Professional damp meter
- Deep-reading moisture meter
- Non-invasive moisture scanner
Survey Checks
- Accessible walls, floors and ceilings
- Visible plumbing and drainage leak checks
- Subsurface moisture readings
- Non-invasive scanning of appropriate materials
- Accessible underfloor and subfloor checks
- Wet rot inspection
- Dry rot inspection
- Woodworm inspection
- Damp prevention information
Suitable For
This level is intended for customers who require a more detailed inspection of dampness and timber condition. It is appropriate when moisture may be concealed within building materials or beneath accessible flooring.
The survey may identify evidence of timber decay or wood-boring insects and assess moisture in locations that cannot be properly examined with a surface meter alone.
Level 2 is particularly useful for homebuyers and sellers who want more information about damp and timber before completing a transaction.
The amount paid for the survey will be deducted from repairs undertaken by us.
Full Damp and Property Condition Survey
Standard price: £499 + VAT
Special offer: £399 + VAT until the end of this month
Level 3 is our most detailed inspection. It combines the checks from Levels 1 and 2 with advanced diagnostic technology, ventilation measurements and external roof-level assessment.
Equipment Included
- Professional damp meter
- Deep-reading moisture meter
- Non-invasive moisture scanner
- Thermal imaging camera
- Indoor humidity sensor
- HD borescope camera
- Airflow and ventilation tester
- 4K inspection drone
- Socket and RCD testing device
Survey Checks
- Accessible walls, floors and ceilings
- Visible plumbing and drainage
- Deep moisture investigation
- Non-destructive moisture scanning
- Accessible floor voids and subfloors
- Wet rot, dry rot and woodworm
- Infrared thermal imaging
- Indoor relative humidity
- Extractor-fan performance
- Borescope examination where suitable
- Visible damp-proof course
- External brickwork and pointing
- Roof coverings and junctions
- Chimney stacks and flashing
- Guttering and rainwater systems
- High-level exterior areas
- General visible structural condition
- Basic Electrical Test, socket and RCD screening
- Drone photographs, subject to safe flying conditions
Suitable For
The Level 3 survey is recommended for buyers, sellers and existing owners who want the most extensive moisture assessment available.
It is especially useful for older properties, houses with several reported defects, basement buildings and cases involving damp, mould, leaks, poor ventilation, timber decay or roof problems.
The inspection considers the property as a connected building rather than examining only the visible damp patch. A roof or gutter defect, for example, may allow water to enter at a high level and appear some distance away internally.
The drone component provides valuable information about roofs, chimneys, parapets and guttering that cannot normally be seen from the ground. These areas may contain hidden repair costs capable of affecting a property purchase.
Identifying damage before buying can help the purchaser budget correctly, request further specialist advice or use the findings during negotiations. Even a relatively small roof defect may cost more to repair than the difference between the survey packages.
If we complete the recommended remedial work, your survey payment will be credited against the price.
Specialist Survey Add-On Services
For complex damp investigations, we offer three specialised laboratory and environmental testing add-ons:
Laboratory Analysis of Plaster Samples
Price £299 + VAT
Description: Small plaster samples are extracted from affected masonry walls and submitted to an independent testing laboratory. The lab analyses the sample for hygroscopic salts (specifically nitrates and chlorides).
Value: Scientifically differentiates true rising damp (which deposits ground salts over time) from surface condensation or lateral penetrating damp. Ensures that remedial recommendations are based on chemical analysis rather than surface meter readings alone.
This service can be beneficial when:
- The cause of low-level dampness is disputed.
- Moisture-meter readings are inconsistent.
- A property has undergone previous damp-proofing.
- Old plaster continues to attract moisture.
- Independent laboratory evidence is required.
- Several possible moisture sources are present.
Note: Salt analysis is only one part of the investigation. Results must be assessed alongside the location of moisture, condition of the masonry, external ground levels, damp-proof course and potential plumbing or rainwater defects. Requires minor invasive plaster sampling (the only add-on requiring material removal). Survey fee credited when repairs are completed by us.
Mould Identification & qPCR DNA Testing
Price £299 + VAT
Description: Surface swab samples are collected and sent to an accredited laboratory for advanced qPCR DNA analysis. Identifies exact mould species, measures spore concentrations and detects hidden fungal growth behind furniture, within void spaces, or under floorboards.
Value: Provides precise scientific data regarding mould toxicity and contamination levels, helping establish the exact scale of cleaning, drying and structural remediation needed.
Laboratory mould testing may be useful when:
- There is an unexplained musty odour.
- Visible mould repeatedly returns.
- Water damage occurred previously.
- Mould is suspected behind cupboards or furniture.
- Contamination may be present in a concealed location.
- The visible extent of growth is uncertain.
- Independent results are needed.
- Remediation work is being planned.
Note: The results can provide a clearer indication of whether contamination appears minor, concentrated or potentially widespread. This information may be used when deciding the scale of cleaning, removal, drying or remedial work required. Testing should be combined with an investigation of the moisture source. Removing visible mould without resolving the underlying condensation, leak or ventilation problem may allow it to return. Survey fee credited against subsequent remediation works completed by us.
Air Quality, Gas, Vapour & Airborne Particle Screening
Price £299 + VAT
Description: Comprehensive environmental air testing including:
- Indoor environmental quality – IAQ
- Volatile organic compounds – VOC and TVOC
- Formaldehyde – HCHO
- Fine airborne particles – PM1.0, PM2.5 and PM10
- Dust and smoke particles
- Sewer gases – H2S, NH3 and CH4
- Flammable gases – CH4 and C3H8
- Carbon monoxide – CO
- Hydrogen sulphide – H2S
- Ammonia – NH3
- Oxygen measurement – O2
- Ventilation and stale-air assessment
- Drain-smell investigation
- Chemical-odour investigation
- Air checks following a leak or flood
- Combustion-related screening
- Building-material off-gassing assessment
- General airborne pollutant monitoring
Value: Pinpoints invisible airborne hazards, toxic sewer gases, chemical off-gassing and foul odours resulting from damp or trapped water.
This service can assist when investigating:
- Persistent foul smells
- Suspected sewer or drain odours
- Chemical smells
- Stale indoor air
- Odours following water damage
- Possible stagnant water
- Building material emissions
- Fine dust after construction work
- Poorly ventilated rooms
Note: Unpleasant odours can have several possible sources. Measurements for specific gases, compounds and particles may help identify which source requires further investigation. The assessment is a screening service and does not replace specialist gas-safety, environmental or medical testing where this is necessary. Survey fee credited against subsequent repair works completed by us.
