Persistent smell in your home? We find exactly where it is coming from
A smell that will not go away is almost always a sign of something that needs to be addressed. At Intra Air, we carry out professional odour investigations to identify the precise source of the problem so it can be properly resolved, not just masked.
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We will be in touch within the hour during business hours. No obligation whatsoever.
Smells we investigate
What is an odour investigation?
An odour investigation is a professional inspection designed to identify the source and cause of persistent or unexplained smells in a property. Rather than using air fresheners or surface treatments that cover the problem temporarily, we trace the smell to its origin. Persistent odours in a home or workplace are commonly caused by sewer gas escaping from drains or pipework, and smells travelling in from neighbouring properties, mould, damp, poor ventilation, drainage issues, pests, or residual contamination from previous use of the property. Many of these causes are not visible and require specialist equipment and expertise to identify. Our investigation gives you a clear, evidence-based answer about what is causing the smell and what needs to happen to eliminate it for good.
Smells we investigate
- Sewage and drain smells, including a rotten-egg smell
- Musty and damp smells from mould and moisture
- Cigarette, cannabis, smoke and burnt smells
- Cooking and food smells
- Pet, urine and ammonia smells
- Stale, stuffy air and carpet odours
- Smells from under floors, voids and lofts, including suspected dead animals or pests
- Smells coming in from neighbouring properties
When should you call us?
A smell that has been present for weeks or months with no obvious cause
A smell that gets worse in certain rooms or after rain
A smell that returns after cleaning or using air fresheners
Family members experiencing headaches, nausea or irritation that may be linked to the smell
A smell that started after building work, flooding or a change in the property
You are preparing to sell or let a property and need to resolve a smell before viewings
A sewage or drain smell inside the house that comes and goes
Cigarette, cannabis or cooking smells coming in from a neighbouring property
Musty or Damp Smell in Your House? We’ll Find the Cause
A musty smell is usually a sign of mould or moisture somewhere in the property, often where you can’t see it: behind furniture, under floors, inside wall cavities or in a loft. Air fresheners and cleaning only mask it, and it comes back because the cause is still there.
Common causes
- Hidden mould behind furniture, inside cupboards or under flooring
- Condensation and poor ventilation
- Leaks from pipes, roofs or windows
- Damp in walls or floor voids
- Wet carpets, underlay or insulation after a leak
How we find it
We measure humidity, use moisture meters and thermal imaging to find hidden damp and cold spots, and take air samples for laboratory analysis where needed. You receive a written report showing the source and what needs to be done. Once the cause is fixed, our mould removal and odour treatment services clear what’s left.Available across Derby, Burton, Nottingham, Leicester and the Midlands.
How does an odour investigation work?
Our specialist visits your property and carries out a systematic investigation to identify the source and cause of the smell. We use specialist equipment to measure air quality, moisture levels and ventilation, and we examine the areas most likely to be contributing to the problem. We do not simply follow our nose. We use data and measurement to build a clear picture of what is happening throughout the property. This approach means we find the actual source, including hidden causes inside walls, floors or structural elements that a visual inspection would miss. Following the investigation, we provide you with a clear explanation of our findings and a recommended course of action.
Where a smell is travelling from somewhere else, such as a drain, a void or the property next door, we use smoke testing. Harmless, non-toxic smoke is introduced at the suspected source, and we watch where it appears. It shows the exact route the smell is taking, so it can be sealed or repaired properly.
Our step-by-step approach
- Understanding the problem: we ask detailed questions about the smell (when it happens, where, what it’s like) before we visit.
- On-site investigation: our specialists take odour and air measurements, inspect hidden areas and take air samples for laboratory analysis.
- Finding the cause: we often identify the source on the day; if not, laboratory analysis confirms it.
- Report: within 5 to 7 working days, a clear report by email with what we found, the laboratory results and our recommendations.
- Solving it (optional): we can remove the smell with our odour or ozone treatment once the source has been dealt with.
Sewage or Drain Smell in Your House? We’ll Find the Source
A sewage or drain smell inside your home is one of the most unpleasant problems to live with, and one of the hardest to pin down. It often comes and goes, appears after heavy rain or at night, or only in one room. Air fresheners and cleaning won’t fix it, because the smell is usually sewer gas escaping from the drainage system somewhere it shouldn’t.
Common causes of a sewage smell in the house
- Dried-out traps in sinks, showers, baths or floor drains that are rarely used
- Failed or missing seals around toilets and waste pipes
- Cracked, loose or poorly connected pipes hidden inside walls or under floors
- Faulty air admittance valves, or a blocked or damaged vent stack
- Old pipework left open or badly capped after renovation work
How we find it
We inspect the bathrooms, kitchen and drainage points, measure for hydrogen sulphide (the gas behind the rotten-egg smell) and other sewer gases, then use smoke testing. Non-toxic smoke is introduced into the drainage system and we trace exactly where it escapes into the property. It’s the most reliable way to find a hidden leak without unnecessary digging or removing floors and walls.
What you get
A clear written report showing the source, with photos, and what needs to be done. A plumber or drainage contractor can then fix the right thing first time. Once the source is repaired, we can remove any lingering smell with our odour treatment service.
Safety note
If you smell gas (a smell like rotten eggs that could be mains gas), don’t wait. Leave the property and call the National Gas Emergency line on 0800 111 999.
Smells Coming From Next Door? Odour Transfer Investigations
In flats, terraced and semi-detached houses, conversions and HMOs, smells don’t always stay where they start. Cigarette and cannabis smoke, cooking smells, pet odours and drain smells can travel between properties through gaps you can’t see.
How smells get in
- Gaps around pipes and cables passing through walls, floors and ceilings
- Shared floor voids, ceiling voids and lofts
- Chimney breasts and old flues
- Shared ventilation ducts and extractor routes
- Cracks and unsealed joints in party walls and floors
How we investigate
Harmless smoke is released in stages where the smell starts, while we watch the affected rooms to see exactly where it appears. Where smoke alone isn’t conclusive, we use particle meters to track how air moves through the building, together with an inspection of the likely routes. Once we can see where the smell gets in, it can be sealed at the source, which is often a straightforward job once you know where to look.
What you get
A written report with photos showing each route we found and how to seal it. It gives you independent evidence to share with a landlord, letting agent, management company or neighbour.
Find where the smell is getting in
Why choose Intra Air for odour investigation?
Persistent smells are one of the most frustrating problems a homeowner can face because they are often difficult to locate and easy to mask without actually solving. Our approach is different. We investigate thoroughly, we measure, and we give you a clear answer. We will not recommend treatment until we are confident we have found the cause. And when we do recommend action, it will be targeted at the actual source of the problem, not a general treatment that may or may not work. Covering Derby, Nottingham, Leicester, Birmingham and the wider Midlands.
- Source-first approach, we find the cause before recommending treatment
- Specialist equipment for accurate diagnosis
- Clear explanation of findings with no jargon
Smell problem in a business, hotel or rental property? See our commercial services.
Landlords: unresolved smells can affect tenancies and property value
Persistent odours in a rental property can lead to tenant complaints, difficult tenancy renewals and reduced property value. An independent professional investigation establishes the cause on record and enables a targeted, effective treatment. We work with landlords and letting agents across the Midlands to investigate and resolve odour complaints quickly, with written documentation you can keep on file.
What our customers say
“I never knew that we could employ a contractor to trace a smell, and what a difference it’s made. We can deal with the issue direct without having to try different things, well worth it.”
“We have had great support from Emeka and Reuben in identifying where an unpleasant odour has come from.From the moment of contacting them at Intra Air we found them really helpful and professional.They scheduled their visit around our needs and arrived on time with a real can do attitude. Both young men were extremely pleasant and courteous throughout.They carefully explained what they were going to do at each step and kept us informed of progress throughout. Their equipment was first rate and they were proficient in its use.”
“Called Intra Air out to take some air samples as we suspected we had a mould issue. They fitted us in and were very professional, the report they sent us was very through and helpful. They answered all our questions during and after taking the tests giving us good feedback and advice. All the staff were friendly, helpful and professional.”
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Frequently Asked Questions
Yes. Intermittent smells that worsen under certain conditions are often the most informative for diagnosis. Tell us as much as you can about when and where the smell is strongest and we will factor this into our investigation.
In our experience, there is always a source. Some investigations take longer than others and may require follow-up measurements. We will always be transparent with you about what we have found and what further steps may be needed.
No. We can carry out the investigation independently and provide you with findings and recommendations. You are under no obligation to book a treatment with us, though we are happy to provide one if needed.
Most sewage smells aren’t caused by blockages. They’re usually sewer gas escaping through a dried-out trap, a failed seal or a cracked pipe. Smoke testing finds exactly where.
Changes in weather, wind, heavy rain and water use all change the air pressure in the drainage system, so gas escapes at some times and not others. That’s why the pattern of when you notice it helps us find the source.
Sewer gas is unpleasant and shouldn’t be ignored, especially if it’s strong or getting worse. Ventilate the room and get it investigated. If you think you can smell mains gas, leave the property and call 0800 111 999.
Yes. The smoke is non-toxic, leaves no residue and clears quickly once the test is finished.
We find exactly how the smoke is getting into your home and recommend how to seal those routes. Sealing the right gaps usually makes a significant difference.
Yes. Once the source has been fixed, our odour treatment and ozone treatment services remove any smell that’s left behind.
Yes, including offices, hotels, restaurants, shops and rental properties. See our commercial services.
Ready to solve the problem for good?
Whether it is mould, damp, odours, ventilation or air quality, we are here to help. Get in touch today and we will assess your situation, explain your options clearly, and give you a solution that lasts.