hen testing your concrete slab, make tests in several areas of each
room on both old and new slabs. When tests
indicate too much moisture in the slab, do
not install hardwood floors. For a moist
slab, wait until it dries naturally, or accelerate
drying with heat and ventilation then
test again.
1) The Rubber Mat Test. Lay a smooth, non-corrugated
rubber mat on the slab, place a weight on top to
prevent moisture from escaping, and allow the mat to
remain 24 hours. If the covered area shows water
marks when the mat is removed too much moisture
is present. This test is worthless if the slab surface is
other than light in color originally.
2) The Polyethylene Film Test. Tape a one-foot square
of 6 mil clear polyethylene film to the slab, sealing all
edges with plastic moisture resistant tape. If, after 24
hours, there is no "clouding" or drops of moisture on
the underside of the film, the slab can be considered
dry enough to install wood floors.
3) The Calcium Chloride Test. Place a quarter teaspoonful
of dry (anhydrous) Calcium Chloride crystals
inside a 3-inch diameter putty ring on the slab.
Cover with a glass so the crystals are totally sealed
off from the air. If the crystals dissolve within 12 hours
the slab is too wet.
4) The Phenolphthalein Test. Put several drops of a
3% Phenolphthalein solution in grain alcohol at various
spots on the slab. If a red color develops in a few
minutes, too much moisture is present.
Flooring Installation Guide :: Index
1) Installation Introduction
2) Handling & Storage
3) Job Site Conditions
3.1) Installing over Concrete
3.2) Testing Concrete for Excessive Moisture
3.3) Concrete Slab Preparation Prior to Installation
4) Laying & Fastening
5) Plank Flooring
6) Laying a New Strip Floor Over an Old Floor
7) Parquet, Block Herringbone & Similar Flooring
8) Special Construction Situations
9) Tips for Easier & Better Flooring Installations
10) Strip Flooring on Walls & Ceilings
11) Installation of Gymnasium Floors over a Concrete Slab
Installation content courtesy of NOFMA. FloorMall.com is a Proud Member of NWFA.
