Urea-formaldehyde foam insulation is a foam that was mixed on site and injected into closed wall cavities as a retrofit, mainly in the late 1970s, a period when federal home-insulation funding was available in Canada. Its sale was prohibited in Canada in 1980. It cures in place and, as it cures, it shrinks — which is why installations are often described as leaving gaps.

How can I tell if a house has UFFI?

The usual first sign is a row of patched injection holes, roughly the diameter of a broom handle, spaced along the exterior cladding or occasionally on interior walls, often near the top of each stud cavity. Foam is sometimes visible behind an electrical outlet or switch cover plate. Both are prompts to investigate, not confirmation: other retrofit insulation is installed the same way and leaves the same pattern of holes.

Is UFFI still a health risk in a house today?

The concern associated with UFFI is formaldehyde released as the foam cured, which is why the material was prohibited for sale in 1980. Health Canada's guidance addresses formaldehyde in indoor air generally rather than treating decades-old installed material as an assumed source. What matters for a specific house is the current indoor air, not the era — and that is established by testing, not by the build year or by the presence of injection holes.

Does UFFI have to be disclosed when selling a Canadian home?

Seller disclosure obligations are provincial, and the standard forms some brokerages use ask about UFFI specifically. Because the requirement and the wording differ by jurisdiction, confirm what applies with a real estate lawyer or notary, or your provincial real estate authority, rather than relying on a national rule. What a seller knows and what a form asks are separate questions from what is actually in the walls.

Should UFFI be removed?

That is a decision for a qualified assessor looking at the specific building, not a general rule. Removal means opening wall assemblies, which is invasive and can raise separate questions about what else is in the wall — older insulation, wiring, or materials that need testing before disturbance. Where foam has been wetted, the moisture source and the condition of the surrounding assembly are usually the more urgent questions.

Will UFFI affect a mortgage or insurance in Canada?

It can come up, because some application forms ask about it directly as a legacy of the 1980 prohibition. What any particular lender or insurer does with the answer differs between them and changes over time. Ask yours in writing what they require — an assessment, a test result, or a disclosure statement — before you rely on any assumption.

Insulation reference · 1970s retrofit

UFFI — Urea-Formaldehyde Foam Insulation

Injected into Canadian wall cavities as a retrofit in the late 1970s and prohibited for sale in 1980. Two questions about it get conflated constantly: whether it is there, and whether it matters now. They are answered by different evidence.

Does a house built before 1980 have UFFI?

Construction era does not establish it. UFFI was a retrofit injected into existing walls, so it is tied to when a house was insulated rather than when it was built, and it was one of several products installed the same way. Patched injection holes indicate that something was injected — a qualified assessment of the cavity is what identifies which material.

What this means

Injection patching on an older Canadian home is a reason to ask what was injected, when, and whether any indoor air testing has been done.

What it does not mean

It does not establish that UFFI is present, that formaldehyde is being released today, or that anything needs removing. Presence and current condition are separate findings, and neither follows from the era.

How to verify

Have a qualified assessor identify the cavity material rather than inferring it from hole pattern
Ask the seller in writing what retrofit insulation was installed and when
Where indoor air is the concern, test for formaldehyde and record the method used
Ask any lender or insurer in writing what they require, since some forms ask about UFFI directly

Two separate questions

Is it present?

Answered by a qualified assessment of the wall cavity, plus whatever documentation exists about retrofit insulation work.

Injection holes show something was injected, not what
Other retrofit products leave the same pattern
Foam visible behind a cover plate is an observation, not an identification

Does it matter now?

A separate question, answered by the current indoor air and the condition of the assembly — not by the material's history.

Health Canada addresses formaldehyde in indoor air generally
Testing produces a result for an address; era does not
Where foam has been wetted, the moisture source is the live question

What a walkthrough can and cannot show

Rows of patched holes, roughly broom-handle diameter, spaced along the cladding — often near the top of each stud cavity.
On brick or stucco the patches may be mortar-coloured plugs; on siding they may sit beneath a course and be easy to miss.
Foam sometimes visible at an electrical outlet or switch when the cover plate is removed — do this only with the circuit off, or have an electrician do it.
Cured foam is often described as light yellow to tan and crumbly when aged, but appearance alone does not identify a product.
None of the above distinguishes UFFI from other injected retrofit insulation. Only an assessment does.

Opening a wall in an older house raises separate questions about what else is in the assembly. Where materials of unknown composition may be disturbed, ask a qualified assessor first — see vermiculite insulation and asbestos cement siding.

Records and written answers to request

Seller's written statement of what retrofit insulation was installed, by whom, and in what year.
Any invoice, grant record or programme paperwork from an insulation retrofit.
Any previous assessment or indoor air test result, with the testing method recorded alongside it.
Municipal permit history, which may record a retrofit even where the owner's paperwork is gone.
The lender's and insurer's written answer on what they require, since some forms ask about UFFI by name.

Where records are missing, record that as unknown. An absent record is not evidence that no retrofit occurred. Provincial record sources are listed by jurisdiction in the provincial source directory.

My Observation Log

For UFFI Insulation

Patched injection holes observed, and their pattern photographedobservation

Foam observed behind an outlet or switch cover plateobservation

Any signs of water entry near the affected walls recordedobservation

Seller's written statement about retrofit insulation, if anydocument

Qualified assessor's written report identifying the cavity materialdocument

Indoor air test result for formaldehyde, with method noteddocument

Lender or insurer's written answer on what they requiredocument

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Evidence note

Sources

Jurisdiction

Canada (federal indoor-air guidance; seller disclosure obligations and real estate forms are provincial)

Applies to

Canadian homes insulated by cavity injection, principally in the late 1970s

Last reviewed

2026-09 (sources checked 2026-09-03)

Limitations

This page describes a material and how its presence and condition are established separately. It does not identify what is in any wall, does not interpret an air test, does not state a health outcome for any occupant, and publishes no cost figures. Disclosure requirements differ by province.

What you should verify

Have a qualified assessor identify the cavity material, test indoor air where that is the concern and record the method, and get any lender or insurer requirement in writing.

Elsewhere in the network

Related sites for the parts of this that sit outside the wall assembly.

HomeCosts.ca

This site publishes no cost figures; use written quotes and wider cost planning there.

RealPartners.ca

Working with a representative where disclosure or a lender question is involved.

CondoSale.ca

Where the building is a condominium and the assembly is common property.