FAQs - Adhesives
|How important is the use of the recommended trowel?
Most flooring adhesives are applied with a notched trowel. The size of the notching is important because it controls the amount
of adhesive applied. Notches which are too large spread too much adhesive. This can cause excessive indentations to show through
sheet goods and trowel mark show-through or bleeding at tile joints. Using too much adhesive with Interflex material can cause
swelling and buckling where the adhesive is applied. Always check the adhesive label for the proper notching.
Why must I use the recommended trowel for spreading adhesive?
Trowels are chosen for the amount of adhesive they place on the substrate. A trowel is chosen to place just the proper amount
of adhesive where it is needed. If the notches are too large, they place too much adhesive which can lead to trowel-mark showthrough
and bleeding with tile and excessive indentations with sheet goods. With Interflex flooring, too much adhesive may cause swelling
and buckling of the flooring. If the trowel notches are too small, the adhesive will not hold the flooring down.
What is meant by open time?
Open time is the amount of time recommended for the adhesive to set before it is covered with the flooring. Open time is affected
by temperature, humidity and porosity of the subfloor. Placing sheet flooring into the adhesive too soon may cause the flooring
to bubble. Placing tile into the adhesive too soon may cause the tile to move and adhesive to ooze up between the tile joints.
What is meant by working time?
Working time for tile is the amount of time from when the adhesive is set until the tile will no longer bond. Working time
for sheet flooring is the amount of time from when the flooring is laid in place until all cutting and fitting must be completed.
Working time is affected by temperature, humidity and porosity of the subfloor. Placing flooring into the adhesive after the
working time has passed will result in a failed installation as the flooring will not bond.
What does "dry to the touch" mean?
Dry to the touch means when you place your fingertips lightly on the adhesive ridges, no adhesive transfers to them. All Armstrong
resilient tile adhesives require the adhesive be dry to the touch before installation may begin.
I spread tile adhesive 2 hours ago, and the recommendations say open time is 1 hour or until dry to the touch. The adhesive
is still wet. Why?
If a larger notch trowel than recommended is used, too much adhesive is spread, and this will increase the amount of open
time required for the adhesive to be dry to the touch. If there is moisture in the subfloor this too can cause retarded setting
of the adhesive. If the controlled climate is not in use in the building where the tile is being installed, and the outdoor
temperature and humidity are high, the setup time is greatly increased. This will especially happen on hot, humid summer days
or rainy days. When the adhesive is spread on days like this, moisture can condense on the surface of the adhesive, severely
slowing the setup.