Make sure to test moisture vapor transmission and alkalinity of the concrete slab before painting, coating, or installing flooring. The calcium chloride test kits and pH test kits from VaporGauge make it easy and affordable for flooring contractors, as well as homeowners.
The test kits are complete and include free support and services:
The calcium chloride test kits measure the water vapor transmission rate from the surface of a concrete slab. Also called dome test kits, they use the Anhydrous Calcium Chloride Vapor Emission Method and conform to ASTM (American Society for Testing and Materials) F-1869 and F1907-04.
As a desiccant, calcium chloride absorbs moisture from the air. A small container with calcium chloride is placed on the concrete floor and covered by a plastic dome. A unique, heavy-duty red dome helps prevent tripping accidents. After 60-72 hours, the calcium chloride dish is cut out. The vapor transmission rate is calculated from the weight difference of the calcium chloride at the beginning and end of the test.
For new construction, ASTM requires 3 kits for the first 1,000 sq. ft. and at least 1 kit for each additional 1,000 sq. ft. The temperature of the surface should be in the range 50-70°F. The internal conditions in the room should be 40-60% humidity and 65-85°F.
New concrete is highly caustic, which may attack adhesives, paints, and flooring materials. As concrete ages and reacts with carbon dioxide in the air, the alkalinity of its surface gradually decreases.
One pH test kit, which conforms to ASTM F710, is included with each vapor test kit. ASTM states that a pH test should be performed along with every moisture test. Flooring manufacturers insist on pH testing before the installation of flooring.
You can send the calcium chloride container back to VaporGauge for weighing and a formal report. Or you can get it weighed in a friendly drugstore. Or, purchase the high-precision pocket scale, which has many other potential uses.
The scale features a beautiful modern design, a large backlit LCD display, a stainless steel platform, and multiple units and functions. Accuracy 0.1 gram and capacity 150 grams (5.291 oz.).
Not sold in stores but delivered directly from the factory to your door. Orders are normally shipped within 24 hours and delivered by courier (UPS) within 2 to 5 workdays within the lower 48 states.
|Vapor Transmission Test Kits|
|Vapor Transmission Test Kit (single)||$17||$6|
|3-Pack of Vapor Test Kits||$43||$8|
|12-Pack of Vapor Test Kits||$159||$10|
|100-Pack of Vapor Test Kits||$1,099||$29|
|Pocket Digital Scale||$49||$7|
Based on shipping by courier to the lower 48 states. For expedited shipping or
shipping to other states and Canada, please inquire first by e-mail or telephone.
Moisture emissions from concrete and its pH level make or break the success of any floor covering installation. The flooring manufacturers’ warranty becomes void if moisture or alkalinity exceed stated limits.
Concrete is very porous. Water vapor from the concrete or the ground below flows through the pores and gets trapped under impermeable coating or flooring. The vapor pressure can lift epoxy coating or vinyl tiles. High moisture will buckle hardwood floors. Trapped moisture can cause molds, which also attack wood flooring.
New concrete is very caustic with a typical pH of 11 to 13. As it ages, it reacts with carbon dioxide in the air and the alkalinity of its surface gradually drops. The alkalis from concrete, mainly lime - the by-product of its curing, attack and break down adhesives, paints, vinyl tiles, carpet padding, etc.
When the alkalis attack plastics, it may cause “plasticizer migration” into the concrete, resulting in a noxious smell from the concrete even after the flooring has been removed. (Instead of removing the slab, seal it with RadonSeal!).
This test has been used for more than 50 years. The ASTM E 1907 describes the test procedure which is still accepted by some flooring manufacturers.
Use a 18 in. (460 mm) square transparent polyethylene sheet at least 4 mils (0.10 mm) thick. Tape it to the concrete slab with a 2 in. wide duct tape – all edges must be sealed tight. Leave the plastic sheet in place for at least 16 hours. Then, remove the sheet and check for the presence of moisture – droplets on the underside of the sheet or on the concrete, a darker color of the concrete surface.
Years ago, when flooring adhesives were more moisture resistant than now, this test was sufficient before installing flooring. However, this test does not give a reliable indication of the floor moisture condition.
16 hours is not long enough to reflect the moisture movement from the bottom to the top of the slab but it largely indicates the conditions of the surface. It may also reflect condensation on the surface instead of the moisture flow through the slab.
Once the concrete surface is covered, water cannot evaporate and the moisture levels equalize through the slab. This may also bring to the surface more alkalis from inside the concrete.
When the concrete slab is exposed to water from the ground, it slowly deteriorates. The pores get larger and the concrete passes more water vapor and even wicks up liquid water.
So, the vapor transmission and alkalinity tests cannot offer a 100% guarantee of long-term successful floor covering installation. There is still some uncertainty. No wonder that the flooring manufacturers set the limits conservatively low.
Most flooring manufacturers and ASTM set the vapor transmission limit at 3 lbs/1,000 sq. ft./24 hours. That means less than ½ gallon of water may pass through an area of 1,000 sq. ft. per day.
However, a manufacturer reports that 96% of tested slabs exceed the limit. Really porous slabs exceed 10 or even 15 lbs/1,000 sq. ft./24 hours.
Some slabs may be very porous due to the concrete mix or a high water/cement ratio. Several flooring manufacturers now insist that there must be a vapor retarder underneath the slab.
The flooring warranties require that the alkalinity of the concrete surface cannot exceed pH level 9.
The concrete must be at least 1 month old before installing flooring but many contractors wait for several months.
There are epoxy or hybrid coatings, and special membranes. Many flooring contractors just put down a plastic sheet before installing hardwood flooring.
The moisture and alkalinity will over time break down any coating. Plastic sheets or membranes trap all moisture and may cause molds and mildew. But this takes time and will usually outlast the 5-year warranty on flooring.
The better solution is to deep-seal the concrete slab with RadonSeal Penetrating Concrete Sealer. It reacts deep inside the concrete and seals it permanently. As it passes through the surface, it neutralizes lime and alkalis, reducing its alkalinity. It hardens the surface but does not change its profile – leaves the concrete suitable for paints, adhesives, thinset, etc.
Wait at least 10 days and seal the slab again with Ion-Bond Armor. It also seals inside the concrete, has smaller molecules and bonds with RadonSeal. The surface remains suitable for paints or adhesives. This sealer combination was successful on slabs exceeding 14 lbs/1,000/24 and is easy to apply for contractors or homeowners.