Some odours cannot be cleaned out of a building because the building itself is the source. Creosote-treated sills, posts, and joists, coal-tar-coated masonry, old chimney breasts, and smoke-saturated heritage brick keep releasing semi-volatile compounds — including polycyclic aromatic hydrocarbons (PAHs) and phenolics — for decades. Airing out the space, running ozone, or repainting buys days, not years.
Our encapsulation service treats the source. We contain the work area under negative pressure, mechanically prepare the substrate back to sound material, and apply a dual-coat Zinsser B-I-N shellac vapor seal that blocks the migration path out of the wood or masonry — then verify with air sampling where the file requires proof.
Our industry-standard protocol
- 1
Source identification & baseline sampling
Walk-through with olfactory mapping, moisture readings, and substrate identification (creosote-treated timber, coal-tar masonry coating, smoke-saturated brick, phenolic residue). Baseline VOC/PAH sampling coordinated through an accredited lab where verification is required.
- 2
Containment & negative pressure
Critical-barrier polyethylene containment, HVAC isolation and register sealing, and HEPA negative-air machines exhausted to exterior so prep dust and vapor never migrate into occupied space. Differential pressure logged during work.
- 3
Mechanical substrate preparation
HEPA-shrouded sanding, wire brushing, or media blasting matched to the substrate to strip surface char, loose fibre, efflorescence, dust, and failed coatings. Shellac bonds to sound material — this step determines the service life of the seal.
- 4
Dual-coat shellac vapor sealing
Two full coats of Zinsser B-I-N shellac-based primer: a penetrating first coat keyed into the prepared substrate, then a build coat closing pinholes, checks, and end-grain. Full coverage of all six faces of exposed framing where accessible.
- 5
Air scrubbing, cure & finish
HEPA and activated-carbon air scrubbing through cure, followed by optional topcoat or finish paint for appearance. Containment struck only after the space passes an odour and readings check.
- 6
Post-work verification & documentation
Post-encapsulation VOC/PAH air sampling where specified, timestamped photo record of prep and both coats, product data sheets, and a close-out letter suitable for adjusters, lenders, or a real-estate transaction file.
What's included
- ✓ Creosote-treated sills, posts, joists & utility timber
- ✓ Coal-tar and smoke-saturated heritage brick
- ✓ Phenolic, tar, campfire & 'railway tie' odours
- ✓ Chimney breast & flue-adjacent masonry odour
- ✓ HEPA negative-air containment during prep
- ✓ HEPA-shrouded sanding, wire brushing & media blasting
- ✓ Dual-coat Zinsser B-I-N shellac vapor sealing
- ✓ Activated-carbon VOC adsorption during work
- ✓ Third-party VOC & PAH air sampling coordination
- ✓ Heritage-appropriate low-aggression prep options
- ✓ Crawlspace, basement & full-structure scopes
- ✓ Close-out documentation for transactions & claims
Where creosote and phenolic odours come from in Eastern Ontario housing stock
Ottawa, Kingston, Brockville, Perth, Almonte, and Carleton Place all carry a deep stock of pre-1960 buildings framed with reclaimed utility timber, railway ties, and creosote-treated sills set directly on stone or rubble foundations. Add coal-fired heating history, old chimney breasts, and unvented crawlspaces, and you get a substrate reservoir that a modern sealed-envelope retrofit will actually make worse: reduce air changes and the odour concentrates.
Seasonality matters too. Warm, humid summer air raises substrate temperature and vapor pressure, so complaints spike in July and August and after any basement waterproofing or spray-foam project that warms and tightens the space.
Related services and reading
- Creosote beam encapsulation (residential basement scope)
- Odour control & deodorization — hydroxyl, thermal fogging, and source removal.
- Mould remediation — musty odour with a microbial source needs S520 remediation, not encapsulation.
- Asbestos abatement (Type 1 & 2) — required before disturbing many pre-1990 coatings and insulations.
- How shellac encapsulation eliminates persistent creosote and phenolic odours
Book an odour source assessment
Send us photos and a short description and a senior coordinator will tell you whether you are dealing with an encapsulation problem, a microbial problem, or both — before anyone quotes a scope.
Where we respond
Crews dispatched 24/7 across Eastern Ontario, including:
Instant cost estimate
Preliminary CAD range in under a minute. A free on-site inspection confirms the scope, and financing is available while your claim is reviewed.
Estimated mitigation range
$3,978 – $5,850
Mitigation and remediation only — we do not quote or perform reconstruction.
Frequently asked questions
What causes that tar, campfire, or 'railway tie' smell in an old basement?
Usually creosote — a coal-tar or oil-borne wood preservative used on sills, posts, joists, and utility timber, and sometimes present in old chimney flues and heritage brick. It continuously off-gasses semi-volatile organic compounds including polycyclic aromatic hydrocarbons (PAHs) and phenolics, which is why the odour returns after cleaning or ozone treatment.
Why does cleaning, ozone, or paint fail on creosote odour?
Cleaning and ozone treat what is already in the air. Creosote odour is a source problem: the substrate keeps emitting. Latex or acrylic paint is vapor-permeable and the odour migrates straight back through it, often within days. Only a shellac-based vapor barrier reliably blocks the migration path.
What does dual-coat Zinsser B-I-N shellac encapsulation actually do?
Shellac-based primer forms a dense, low-permeability film that blocks the odour-bearing vapor from leaving the wood or masonry. We apply two full coats — a penetrating first coat that keys into the prepared substrate and a second build coat that closes pinholes and end-grain. Two coats are what make it a vapor seal rather than a stain block.
Do you prepare the substrate first?
Yes, and it is the step that decides whether the seal lasts. We mechanically prep — HEPA-shrouded sanding, wire brushing, or media blasting depending on the substrate — to remove surface char, loose fibre, dust, efflorescence, and old coatings so the shellac bonds to sound material rather than to a contaminated skin.
Can this be done on heritage brick and timber without damaging it?
Yes. Heritage substrates get the lowest-aggression prep that still achieves a sound surface, and coating selection accounts for the assembly's need to manage moisture. On load-bearing heritage timber and soft historic brick we adjust media, pressure, and coverage rather than defaulting to a single method.
Do you test air quality before and after?
We coordinate VOC and PAH air sampling through accredited third-party labs where a project calls for verification — commonly on real-estate transactions, institutional buildings, and files where an occupant has reported health symptoms. Results are delivered with the close-out package.
How long does the work take and when can we re-occupy?
Most residential basement scopes run 48 to 72 hours including containment, prep, two coats, and cure. Shellac primer is fast-curing; re-occupancy typically follows once the space has been ventilated and post-work readings are acceptable. Larger heritage or commercial scopes are staged and quoted individually.