Types of Flooring Adhesives

In many instances flooring cannot be nailed or stapled to the subfloor. This could be because the subfloor is concrete or that, in the case of a kitchen or bathroom, a floating floor is not practical.

In the past glues and adhesives have been either a cement-like powder or solvent-based compound which are swathed onto the floor with notched trowels. The flooring was then pressed to the adhesive and left to dry. These methods are still being implemented but there are new products being used that will not affect those homeowners with allergies.

Powder Adhesives

Tile is almost always installed on floors with a powder-based adhesive. because it comes dry there is not the shipping charges of the pre-mixed mastic. The mortar-like compound is mixed with water using a motorized spatula to get a consistency like porridge and then it is spread on the subfloor. If the mixture is too wet then the wood subfloor can swell.

Solvent Adhesives

These compounds are used for installing hardwood floors. At first there are volatile organic compounds (VOC) present but these dissipate within a week after installation.

Urethane-Based Adhesives

Also called “moisture cure,” these adhesives do not dry hard as the solvent and powder-based glues. Instead they move with the flooring as the wood expands and contracts.

Water-Based Adhesives

Although low in VOC’s these glues are not as strong a the other ones. Still in areas where traffic is not high this adhesive has a good hold.

6  Tips in Applying Adhesives

1.  Never spread more down than you can cover in 15 to 20 minutes

2.  Before installation of flooring always secure the subfloor and check for oily and water-soaked spots.

3.  Check the directions on the adhesive to see to what products it will adhere.

4.  “Flash Time” – Like contact cement the product has to have a dried skin to adhere.

5.  “Wet Lay” – Flooring can be installed immediately.

6.  On concrete – The slab should cure from at least 60-90 days before put down flooring.

Wood Flooring Adhesives

With the exception of “floating floors,” which can be laminate or engineered, floors are fastened to the subfloor by means of nails, staples or an adhesive. With the latter method the type is determined by the material to be used a flooring.

In short, floor adhesives create a chemical bond between the sub floor and the finished floor. This is accomplished by the material changing from a liquid to a solid but each flooring material has differing properties and so the adhesive needs different agents and catalysts to make the bond.

While most plank-wood flooring is nailed or stapled down wood floors can be glued. The most common types of wood flooring for this are the engineered flooring which includes cork and bamboo as well. In homes where hardwood is going on a concrete basement floor 3/4″ planking is glued down to a substrate but it takes a lot of care.

Wood Flooring Adhesives

1. Solvent-Based: These are the old-time glues which are still used today but the installer needs a well-ventilated room as the off-gassing is great at the beginning.

2. Urethane-Based: This is probably the most widely-used of the adhesives as it works on a wide variety of subflooring.

3. Water-Based: This is classed as “very low emission” and promotes health and environmental protection as they are free of solvents or volatile organic compounds (VOC’s). Some contractors complain of the wood swelling if too much is used.

4. Powder Adhesives: This is a water-based adhesive where you add the water on site. The chemical in the compound will absorb most of the water reducing the wood swelling found in other water-based products.

Rules of Engagement

1. 20 Minute Rule – Use only as much adhesive as you can put flooring down in 20 minutes.

2. The adhesive’s spread is controlled by the size of the notches in the trowel.

3. Flash Time – Compound has to cure for a specified time before flooring is put down.

4. Wet-Lay – Flooring can go down down on the adhesive immediately.

5. Concrete floor should be washed with a mild muriatic acid to get rod of debris before flooring goes own or the adhesive won’t bond with the concrete.

6. Expensive – Not all glues are created equally. The good glues are expensive, up to 80 cents a square foot, but don’t scrimp or else you may have part of the floor popping up.

Like any project the proper preparation and using good materials will ensure a lasting job.