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Expert Advice and Solutions for Rising Damp
Rising damp is a problem that affects many properties, but is commonly mistaken for other forms of damp, including penetrating damp and condensation. There are some telltale signs that your problem is caused by rising damp, and if left, rising damp can lead to damage to plasterwork and decorations, rotting skirting boards and leave behind salty residue.
Because rising damp is often confused with other types of damp, it is vitally important to accurately diagnose the problem, before carrying out remedial treatments. If the wrong treatment is carried out, this will not stop the root cause of your issues. This is why you may require a professional surveyor who can carry out a damp and timber survey. They will carry out a thorough investigation of your property, and provide you with a detailed survey outlining their findings.
Rentokil Property Care have a number of CSRT and CSTDB qualified surveyors who are experts in identifying different types of damp, and will provide you with detailed recommendations for treatments, if required.
We are Property Care Association Members and have a number of branches across the United Kingdom, meaning we have qualified and experienced surveyors and technicians local to you.
What is Rising Damp?
In certain conditions water from the ground can be drawn upwards through porous materials such as brickwork, stonework and mortar through a process known as capillary action. The dryer material at the top evaporates water and therefore drags water upwards from the soil. This is because these materials have tiny pores that draw up moisture from the ground, much like drinking through a straw. This is the reason why building regulations state that buildings should be designed with a protective barrier, known as a damp proof course (DPC). A DPC is put in place to prevent water rising up through the brickwork.
Many older buildings were built without damp proof courses, or over time they can begin to break down. Normally, you may not realise the damp proof course has failed until signs of rising damp begin to appear. If you have rising damp in your home, that means a broken, bridged or missing damp proof course is allowing groundwater access to your ground floor walls through capillary action. Because rising damp is caused by moisture from the ground, it will only ever be noticeable on ground floor levels. If there are signs of damp higher up in your property, it is often penetrating damp or a condensation problem.
The upward movement of moisture can result in damp stains on your internal walls, but it can lead to more serious property issues than that. Plasterwork and decorative features will become damp, and over time timber joists and skirting boards with high enough moisture content may start to decay.
As the moisture in the walls evaporates it will leave behind salt stains and tide marks - it is this evaporation that causes decorations and plasterwork to break down. Salty tide marks are the most common indicator of a rising damp issue. Often these are noticeable externally as well. The colour of the stain will depend on what dissolved salts are in your groundwater. If ignored it can lead to further timber issues, including timber decay like wet rot and dry rot, and woodworm infestations. Damp walls may cause heat loss from your property, as the thermal properties of the walls are decreased.
If you are concerned about a rising damp problem and would like professional advice, get in touch with Rentokil Property Care to book a damp and timber survey which can provide a detailed assessment of your damp problem.
What Causes Rising Damp?
The main cause of rising damp is through groundwater rising upwards through walls by the process of capillary action.
Because a damp proof course is used to stop rising damp, if you have a rising damp problem in your home it means that you have either a broken damp proof course, bridged damp proof course or a missing damp proof course. In the case of slate damp proof courses, these can crack due to subsidence and groundwater can then rise upwards. Over time this will result in damp stains on your internal walls, if you have a solid wall property, but it can lead to more serious property issues such as wet rot, dry rot or woodworm.
Contributing factors that can affect a rising damp problem include:
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Wet Ground Conditions: - If ground around your property is continually saturated with water or you live in an area with high water tables or poor drainage, this may increase the rate of capillary action and the extent of a rising damp problem.
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Building Materials: - The size of the capillaries within masonry and building materials means that some products are more susceptible to rising damp than others.
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Bridging of Damp Proof Courses: - Moisture can rise up a wall if there is a pathway that bypasses the existing damp proof course. This is the most common way rising damp occurs, and will not typically require the installation of a new damp proof course. This can be caused when flowerbeds, drives or paths bypass the DPC, meaning moisture can rise upwards through the wall externally. If plasterwork is brought down to the bottom of a wall it can cause an internal bridge of the DPC or touch a damp floor, which may also cause skirting boards to decay over time. Skirting boards are a design feature to hide the fact the plaster does not extend down below any damp proof courses.
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Bridging within a Cavity Wall: - During construction, or when cavity wall insulation is installed incorrectly, debris can drop down and bridge a damp proof course from within. This allows moisture to migrate through and affect internal walls. This will also remove the thermal properties of any cavity wall insulation.
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Abutting Structures: - When new structures are built on existing walls without capping stones or a vertical damp proof membrane, rising damp can occur. The new structure essentially becomes a bridge for moisture to bypass the existing damp proof course in the wall, and can cause damp problems. If water soaks into the top, you can also get damp which runs downwards into the property.
Signs of Rising Damp
Rising damp will only ever occur on ground floor walls, and initially the problem may be subtle to identify. As time goes on you may notice damp patches appearing and if left without treatment the problem could lead to further issues.
Common signs of a rising damp problem in properties include:
Tidemarks and Damp Patches on Walls:
The most common sign of rising damp is a damp stain appearing on ground floor walls, up to around a metre high above the skirting board level. This may appear damp to the touch and is often partnered with salty residue, as hygroscopic salts are left behind on the surface as moisture evaporates.
White Salt Deposits on Ground Floor Walls:
Moisture that rises from the ground contains water soluble salts which may be hygroscopic. These hygroscopic salts travel upwards through the wall by capillary action, migrating through masonry and plasterwork, and as the moisture evaporates, salts are left behind on the surface. The salts, if hygroscopic, can also pull moisture from the atmosphere back into the wall, creating further issues over time. These salts often have the appearance of fluffy white deposits on the wall and can also appear on external walls on brickwork or masonry.
Peeling Wallpaper and Flaking Paint and Bubbling Plaster:
The presence of moisture in the wall will cause damp patches to form on the surfaces of walls, and this can cause wallpaper to peel and deteriorate. It will cause paintwork to flake away and can eventually lead to plasterwork bubbling and falling from the wall, as salt crystals grow and exert pressure.
Decaying skirting boards, floor boards, joists and other timber
If a rising damp problem is left untreated you may notice signs of decaying timber, most commonly skirting boards, joists and floorboards in the localised area. This is because the moisture from the walls has increased the moisture content of timber, to the point where fungal spores can germinate. This can cause timber to warp and become spongy and crumbly.
If you have a fungal decay problem you should organise a damp and timber survey from a professional surveyor, who can provide advice and recommendations on how to solve the problem.
Damp Musty Smells
If a property has wet walls it can create a damp atmosphere in the room and a musty smell will eventually develop. This doesn’t necessarily mean that the problem is caused by rising damp - condensation and penetrating damp can also lead to damp smells.
It does however indicate a problem with damp in your property, which requires attention from a professional to correctly diagnose the problem.
Rising Damp Survey
If you are unsure about what is causing your damp problem, and want a professional surveyor to fully investigate, Rentokil Property Care are here to help. We have a number of CSRT and CSTDB qualified surveyors who can carry out a damp and timber survey to fully understand the problem.
A damp and timber survey is similar to an MOT for a car, but for your property - they will carry out a full inspection and identify any issues they find both inside and outside your property. They will use a range of techniques to investigate damp, aided by tools and equipment to support any diagnosis, and provide you with a full understanding of the problem. They will investigate any other related issues such as structural defects, timber decay and woodworm.
Our local surveyor will then provide you with a survey report, outlining all their findings during the inspection, along with any recommendations that need to be carried out. The survey report will be in an easy to understand format, and any costs for treatments will be provided, as well as long term guarantees, if applicable.
How to Treat Rising Damp
The first step is a thorough investigation by a qualified surveyor, and only once a rising damp problem is confirmed will we recommend remedial damp proofing. They will check moisture levels and the condition of any existing damp proof courses. If you do choose to go ahead with recommended remedial repairs, experienced technicians local to you will take care of your property from start to finish. They will expose affected areas by removing skirting boards before hacking off contaminated plasterwork,
They will then drill injection holes at intervals into mortar joints, which creates a chemical damp proof course, as the silane‑based damp proofing cream penetrates mortar and brickwork to form an impermeable barrier preventing moisture rising upwards.
Affected areas are then replastered with a breathable plaster, which supports the drying process of the walls. The plaster used will be salt retardant, meaning any salts remaining in the wall will not be able to migrate through and damage the new plasterwork. After a period of time and once the walls are dried out thoroughly, you will be able to redecorate.
Our technicians will come prepared with protective floor coverings, Hilti dust extraction units and vacuums in order to keep your property clean and tidy. Where possible they will cover surfaces with dust sheets in order to keep disruption to a minimum. Once all work has been completed and final sign off has taken place, you will then receive a long term guarantee if applicable, giving you peace of mind your rising damp issue has been resolved, and your property is protected long term.
Find out more about our Damp Proof Treatment Process
Is Rising Damp a Myth?
There is a small minority of people who suggest that rising damp is a myth, but there is significant evidence proving this wrong.
Water rising through porous stone and brick through capillary action has been observed for centuries and is easily replicated by putting common building materials into water. There are British Standards on the necessity for damp proof courses in buildings and major research institutions such as the Building Research Establishment discuss the existence of rising damp.
The main problem around rising damp is not its existence, but the fact that it is often misdiagnosed. When damp is misdiagnosed and incorrect remedial treatments are carried out, the root cause of the problem has not been addressed and will often lead to the problem returning. This is why it is so important to have a professional surveyor carry out a thorough damp and timber survey. Diagnosing any damp problem takes time and a thorough inspection of a property is required. Often specialist tools can be used to provide evidence and to fully understand the condition of the property.
This cannot be done quickly, and is the reason that many professional and accredited property preservation companies choose to charge a survey fee.
You can trust the experts at Rentokil Property Care to come to the correct conclusion of any damp problem, and provide you with the correct solution for your property - this is why so often our damp proofing treatments are backed by long term guarantees, up to 30 years for some of our services. We are a proud founder member of the PCA and have numerous CSRT and CSTDB qualified surveyors working from a network of branches across the country.
Buying or Selling a House with Rising Damp
It can be fairly common for older properties to be sold with evidence of damp problems on either external or internal walls. However some mortgage providers may require damp proofing to be carried out before they lend on the mortgage. Sometimes damp issues can be highlighted on a home report when purchasing a property, and it is advised that you carry out your own damp and timber survey to further investigate.
A qualified surveyor from a reputable company will give you an understanding of the full extent of the problem, and any costs associated with remedial repairs. Often you can use this to negotiate the price with the seller, or make a decision if you still wish to go ahead with the purchase.
If you are selling the property with a damp problem, it is advisable to carry out damp repairs before selling the property, in order to prevent the sale falling through, or any prices being renegotiated. When damp treatments are carried out by Rentokil Property Care they are usually backed by damp issues long term guarantees, which can then be passed on to the new property owners. This gives you peace of mind the problem is solved, and the new property would be protected long term.
Why Choose Rentokil Property Care for Rising Damp Solutions?
If you think you have a rising damp problem in your property, you want to trust the company you are working with will get it right first time.
Rentokil Property Care has been working in peoples homes and businesses for over 70 years, correctly identifying property issues and providing long term solutions.
PCA approved: Rentokil Property Care are a proud member of the Property Care Association (PCA) and have a range of CSTDB, CSRT and CSSW qualified surveyors operating out of our network of local branches.
Which? Trusted Trader: We are endorsed by Which? Trusted Trader - meaning our customer service and workmanship has passed the rigorous trading standards assessments.
Trustpilot: Our damp proofing, structural repairs and timber treatments are rated ‘Excellent’ with over 1,000 reviews from our customers - showcasing our professionalism.
Long Term Commitment: From our origins in the 1920’s to the present day, we have outlived our guarantees several times over. This means you can have complete peace of mind from a Rentokil Property Care guarantee - up to 30 years for some of our services.