How to Identify UFFI - Urea Formaldehyde Building Insulation

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UFFI or Urea Formaldehyde Foam Insulation was an insulation retrofit product used in the 1970's. This expanding foam insulation was mixed on-site and then pumped into building wall or other cavities in older buildings which were not previously insulated.

This fun photo shows an insulation retrofit series of projects. In the center of the photo we see pink fiberglass insulating batts. Below the fiberglass insulation we see blown-in loose-fill cellulose insulation. And in the foreground (and under our © notice) we see a crumbly, cracked slab of UFFI foam insulation as well.

Early cancer research on UFFI: Some earlier research on the carcinogenic effect (cancer causing) of urea formaldehyde foam insulation suggested that formaldehyde out gassing from the insulation formed a significant cancer risk. Eventually, additional study suggested that the initial cancer risk from formaldehyde was not supported, at least in this application.

The level of formaldehyde that out gassed from UFFI depended in part on how the foam product was mixed at the site, and not all building insulation projects using this substance produced the same level of formaldehyde.

The level of outgassing formaldehyde from UFFI insulation declined steadily with age. This was an open-cell foam that did not retain its gases long term.

No formaldehyde outgassing found after the foam aged: More interesting was the observation that perhaps largely because this insulation formed an open-celled foam, even if there were high initial formaldehyde out gassing levels, after months or at most a few years, even careful measurements were unable to detect any levels of ongoing formaldehyde out gassing from this material.

• Consider the building age: UFFI is not likely to be found in buildings built after the 1970's; insulation retrofit or add-on projects are more likely to be found in buildings which were built with little or no original insulation, such as homes built before 1960.
• Look for Oozing-out Foam Insulation: in the basement or crawl space, foamed insulation installation often produces an oozing-out insulation leak at the building sills; in the attic you may find the same oozing insulation shown at the top of gable end walls - as seen in our photograph above.
• Probe the insulation - a finger tip is fine: UFFI urea formaldehyde foam insulation is very soft and crumbly. If the foam insulation product you find is quite firm it is probably a newer product such as icynene foam insulation. But beware: another soft foam insulation product is latex foam spray insulation sold in small spray canisters at building supply houses. It's easy to tell the difference. The latex foam spray is not crumbly.

Below we give specific inspection methods useful in building interiors and exteriors that will help spot the types of insulation that may have been added to a building over its life.

How to Spot UFFI Insulation in an Older Home by Indoor Inspections: Insulation Retrofit Projects

Look in basements and crawl spaces for evidence of UFFI (crumbly) foam exuding out into the basement or crawl space at the bottom of wall cavities. Often there were gaps that permitted this foam escape - usually it was just left in place. Where balloon framing techniques were used, depending on the adequacy of fire blocking in wall cavities, foam injected into the walls may have passed between floor levels and easily into an attic (as shown in our photo above) or into the basement or crawl space as shown below in the left hand photo.

Look in un-finished areas such as attics and closets where plaster and lath are left incomplete or where drywall has been omitted during a building retrofit. Our photos below show UFFI insulation pushing on a poly plastic vapor barrier. Someone has cut the poly in the left photo, perhaps to sample the material - a step that was unnecessary if the inspector simply looked down at his or her feet (photo below-right).

You may also be able to see UFFI or other types of foam insulation oozing out from large openings at the sill plate between floors (photo below-left) or UFFI foam may have oozed out of even small wall openings as we show in the right hand photo of an un-finished plaster lath wall (below right).

Look for scalloped drywall on the inside surface of building exterior walls: often the UFFI foam insulation was sprayed with more water content than specified; because the insulating material could be quite wet when first installed, we found that in some old homes which had been renovated by replacing original plaster with drywall, the drywall became wet, bonded to the UFFI, and then actually became sunken or concave along the building exterior walls as the UFFI insulation cured.

We pose that the drywall had become soft while wet, that it bonded to the UFFI in the wall cavity, and that as the UFFI insulation dried and cured it also shrank, pulling the damp drywall sections inwards.

We first spotted this phenomenon in an 1890 home in Wappingers Falls, NY when the home was insulated with UFFI spray in the 1970's.

Looking along the top edge of the baseboard trim at the bottom of the wall we saw that the drywall was in contact with the trim only at the location of the wall studs, and that between each pair of studs the drywall was concave.

How to Spot UFFI Building Insulation in an Older Home by Outdoor Inspections: Insulation Retrofit Through Siding

As our photos show below, plugs may be visible in siding boards, but we warn that they also may have been covered by replacement boards or by a new layer of exterior siding. Also this plug and pump method for blowing insulation into building walls was used for more types of insulation than just UFFI.

• Look for plugs in the building exterior siding, pull a plug to examine the insulation material. As our photographs show above, you may find evidence of circular wall plugs cut into building exterior siding at regular intervals (one opening per stud bay) at one or more elevations on the building.
  
  Pulling one of these wall -cut plugs will give an opening to the building wall cavity where you may find UFFI urea formaldehyde foam insulation (white crumbly foam) or perhaps blown-in cellulose insulation instead. So don't assume the wall plug means the insulation was UFFI.
• Sometimes insulation blow-in holes in walls were covered not with solid materials but with vented or metal plugs, probably just because they were convenient to snap into the hole cut by a hole saw using the same diameter hole cutting blade.
  
  Insulation may also have been blown into building walls by removing and replacing an entire siding board outside, by lifting and replacing aluminum or vinyl exterior siding installed over original walls of another material, or by openings cut into plaster or drywall in the building interior. So absence of wall plugs is not absence of blown-in insulation.

Urea Formaldehyde Foam Insulation UFFI Shrinkage

Look for UFFI foam spray insulation shrinkage: Neither latex foam spray insulation nor icynene foam spray insulation have the shrinkage problem of UFFI. If you have occasion to open a building wall cavity where UFFI was installed, you'll typically see about an inch of shrinkage at each side of the foam insulation block, and you'll see a couple of inches or more of un insulated space at the top of the column of sprayed foam.

The amount of UFFI insulation shrinkage varied from home to home and was probably the result of how precisely the product was mixed during installation, so the amount of shrinkage may vary among buildings. An expert use of thermography or even infra-red scanning of a building exterior wall in cold weather, with the heat on indoors, may be able to detect this insulation shrinkage too.

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