It's worth remembering that most resilient floors never get a chance to actually wear out.

In practice, they often need replacement before they reach that stage because the adhesive has either failed or caused discolouration in the floor surface.

Below are some of the problems relating to adhesives and the technical terms used to describe the issues.

Plasticiser migration

Plasticisers are used in vinyl flooring products to soften the material and improve its flexibility.

They're also used in adhesives to improve tack, or stickiness.

Two common plasticisers are mineral oil and hydrocarbon oil.

When plasticisers leech out - or 'migrate' - from the flooring into the adhesive, they can send the adhesive soft and break down its holding power.

This tends to happen when multi-purpose adhesives are used with vinyl-backed sheet floors.

The best way to avoid plasticiser migration is to only use adhesives that have been specifically recommended by the flooring manufacturer. This ensures that the two products are compatible with each other.

Adhesive failure

When an adhesive doesn't bond properly to the substrate, the problem is often due to dampness in the subfloor, a curing compound on the surface, or weak material or dust on the surface.

If the adhesive doesn't bond properly to the underside of the floor covering, the failure is more likely to be caused by late placement.

That is, the floor covering has been placed on top of the adhesive after it has set.

The problem can also be due to using a worn or incorrectly-sized notched trowel, resulting in poor transfer of adhesive to the floor covering.

In other cases, it could simply be because the wrong adhesive has been used.

Temperature extremes

Adhesives should only be used when the room and subfloor temperatures are within the range specified by the manufacturer.

High temperatures can cause the solvent to evaporate too quickly in solvent-based adhesives, resulting in thickening and early setting.

Low temperatures can result in poor workability and heavy spread.

In the case of emulsion-type adhesives, low temperatures can cause the components to break down and separate.

Shelf life and pot life

Some adhesives have a 'use-by' date stamped on the container or drum, indicating how long the product can be kept on the shelf.

Once this shelf life has expired, you can no longer guarantee that the product will work exactly as you expect it to, because the components might start to deteriorate.

The photo at left shows a sticker with the date of manufacture printed on it.

Although this isn't a use-by date, it still lets you see how old the product is. You should always try to rotate the stock on the shelf, using the older stock first.

Pot life refers to the length of time you have available to use a two-part adhesive once you've mixed the components together, before it becomes thick and unworkable.

It's similar to 'working open time', which we discussed earlier in this section.

Don't forget that the pot life shown on the container will refer to a particular temperature range, such as 20-23° C.

If the temperature is hotter, the pot life will be reduced. If it's colder, the pot life will be increased.

Diagnosing faults

The link below will take you to a table showing some of the typical problems you're likely to see in a floor when the adhesive fails.

It is adapted from the 'Adhesives fault diagnosis' table produced by Forbo Flooring Systems in their publication: Forbo Floorcoverings Installation Guide.

Note that the descriptions of problems and their causes are only generalisations. In practice, there might be other reasons why a particular floor has failed.

Adhesive problems and causes