I’m Dean Webster CSRT/CSTDB & CSSW, and after more than 35 years surveying properties across Kent and the South East, “water ingress” is one of the phrases I write most often in survey reports and one of the ones that confuses homeowners the most. So let’s explain it properly, in plain English.
What water ingress actually means
Put simply, water ingress means the entry of water into a building where it possibly shouldn’t be. That’s it. It’s a broad term, which is exactly why it can cover so many different situations, from a leaking gutter to rising ground water below a basement.
Where it comes from above ground
Above ground, there are three main sources we see time and again:
- Defective rainwater goods (guttering and downpipes)
- Poor weathering around windows and doors
- Poor roof coverings
Defective rainwater goods
The frustrating thing about leaking gutters is that you’ll usually only see them actually failing during heavy rainfall, and most people are sensibly indoors at that exact moment. By the time the rain stops and you step outside, the leak’s stopped too, so the cause disappears just as quickly as it appeared. What you’re left to go on is the evidence it leaves behind indoors, decorative spoiling such as discolouration and staining on plaster finishes.
Poor weathering around windows and doors
This one’s actually easy to catch yourself. Failed sealants and pointing around windows and doors, especially at ground level, are simple to spot if you get into the habit of periodically casting your eye over them. It’s a five minute check that can save a lot of hassle later.
Poor roof coverings
Roof issues are trickier, because you’ll typically have no idea there’s a problem until it’s already spoiled a decorative finish on a wall or ceiling somewhere below. One simple check worth doing yourself: during a period of heavy rain, go up into the loft, put a light on, and have a proper look around, particularly near chimney breasts, for any signs of water getting in. If you do spot something, get in touch with a suitably qualified roofing contractor.
Water ingress below ground
Below ground, in basements and cellars, the picture changes. Whether the cellar is two hundred years old or two years old, the main driver of water ingress is the water table. During periods of prolonged heavy rainfall, the ground surrounding the basement becomes saturated, the water table rises, and in some cases this can lead to localised flooding within the space.
Getting it properly diagnosed
Whatever the source, the most important step is getting a suitably qualified person to investigate it properly. My honest advice is to ask friends and family for recommendations of people they’ve genuinely used themselves, rather than relying on something like Facebook, which can be very hit and miss. The reassuring part is that remedial works are often surprisingly easy and cost effective, and once they’re sorted, most people say the same thing: I should have dealt with that years ago. Being proactive and keeping a building dry always works out cheaper than leaving a problem to grow.
The mix-up that costs people the most
One of the most common misdiagnoses we see happens at first floor level, particularly in Victorian houses, around chimney breasts. Staining and discolouration appears on the decorative finish, and it’s assumed to be water coming in from above roof level. People then spend hundreds, sometimes thousands, of pounds having the chimney attended to. And yet the internal staining persists. Contractors get called back, and more often than not they say they genuinely can’t find any reason water would still be entering the chimney construction. That’s because, very often, it isn’t water ingress at all. It’s interstitial condensation.
What interstitial condensation actually is
Interstitial condensation happens very commonly inside the void of a chimney construction. The staining it produces is usually a light brown or almost yellow colour, and it’s caused by moisture within the construction evaporating through the masonry and plaster into the warmer air of the habitable room. As it does, it carries deposits of sulfates and nitrates from the void with it, and those deposits are what actually cause the discolouration you see on the wall.
Why correct diagnosis matters so much
In reality, it’s often not simply one or the other. A partnership of both condensation and water ingress is more common than a single clean cause. Getting the diagnosis right, and being honest with the customer about what to expect once repairs are made, matters enormously. Don’t expect the internal fabric of a building to dry quickly under normal conditions, even once the cause has genuinely been fixed. If an area has been damp for years, it can take many months, sometimes close to a year, before it’s properly dry enough to redecorate. What you choose to redecorate with afterwards matters too, the wrong finish can trap moisture in and stop that natural drying process from ever completing.
When there’s nothing left to fix above roof level
We’ve seen plenty of cases where a customer has already spent thousands of pounds addressing everything above roof level, and the staining still hasn’t gone. At some point, the honest answer is that there’s genuinely nothing more that can be done up there, and what the customer actually wants is simply a dry, presentable finish inside. In situations like this, there are systems that can be introduced in front of the affected area that still allow the wall to breathe and dry naturally behind the scenes, while giving you the dry internal finish you’re after. Which, ultimately, is all most people ever wanted in the first place.
The bottom line
Water ingress covers a lot of ground, quite literally, from a blocked gutter to rising groundwater under a cellar to condensation that was never water ingress at all. If you’ve noticed staining or discolouration that won’t go away, however much money’s already been spent chasing it, it’s always worth getting a proper, honest diagnosis rather than continuing to guess.
If you’d like more detail on how we identify and deal with water ingress on the ground, our water ingress service page walks through the different sources we look for and how we go about fixing them properly.
You can also find answers to more common damp and timber questions on our FAQs page.
Book a survey or get in touch with the team.
About Dean Webster
Dean Webster is the Managing Director of South East Timber & Damp, based in Woodchurch, Kent. He has over 35 years of hands-on experience surveying and treating damp, timber decay, and structural waterproofing issues across Kent, South East London, and East Sussex. Dean holds the CSRT/CSTDB (Certified Surveyor in Remedial Treatments) and CSSW (Certified Surveyor in Structural Waterproofing) qualifications, the highest recognised credentials in the industry, and is a member of the Property Care Association. He has a particular interest in listed and historic buildings, where treatment needs a more considered approach than standard modern construction.