January 29, 2020
How do I stop chemicals gas vapors from contaminated soils passing though a concrete slab? This is a question I get frequently from owners and environmental mitigation experts.
Chemical contamination vapors tend to pass though a concrete slab and get into the air above. Stopping the migration of the gas through a slab is frequently a requirement of repurposing a space.
The following steps can be used to mitigate chemical vapors into your space above it. Without the right tools these vapors in the air from contamination under that slab can be quite pervasive.
Each job needs to be evaluated on an individual bases. The tools below make the solution less evasive.
Cracks through the Concrete Slab
The most direct way for soil contamination gasses to get in is through cracks. Cracks are the path of least resistance, so most of your vapors come through cracks in the floor. That is a very easy fix Product #684LV – Methyl Methacrylate Crack Healer and Sealer.
The #684LV has about the viscosity (thickness) of diesel fuel. That makes it easy to gravity feed into small cracks small porous areas of the concrete. It welds the cracks back together with a bond strength that is greater than the tensile strength of the concrete. In other words structurally you have the monolithic structure that the concrete was intended to be.
Expansion joints are the also a very direct route for vapors to come in. To seal these joints use Product #632 – Chemical Resistant Joint Filler. This is a highly chemical resistant joint filler. It will not only keep the vapors out. If there is going to be a chemical exposure to the surface there will it will stop the chemicals from attacking your concrete and further contaminating the soils below it.
Sealing the Surface of the Concrete Slab.
The next step is to prime the concrete with Product #12 Chemical Resistant Primer / Sealer.
This is where there is a couple of ways to go. You can apply an additional coat or coats of the #12 or go on to Coating the Concrete Slab below. Our optional translucent Synthetic Anti-Skid Fine may be added to the #12 if it is used in additional coats as a clear sealer.
The Product #12 Primer Sealer can also be mixed with silica sand and used as a patching material for potholes and otherwise damaged concrete if required.
Coating the Concrete Slap
In many cases you will want to install a coating over the concrete slab. There are a number of options for doing this but here are a few of the most common ones. The biggest difference between these coatings is the chemical resistance. Please See Chemical Resistance Chart for a comparison of chemical resistance of the products below. All of these products are 100% solid, zero voc. All of the coatings in this section are highly durable and resist the abrasion of traffic.
UV Resistant Top-Coating
For jobs that will see direct sunlight. It may be desirable to add an ultra violet (UV) Resistant top coating for the systems above.
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Posted by Norm Lambert
July 6, 2017
URETHANE COATING/SEALER GLOSS
EPOXY.COM PRODUCT #442
EPOXY.COM PRODUCT #442 is a two component water- based
aliphatic (non-yellowing) polyurethane. Product #442 is free of the
health and environmental problems normally found in solvent-based
urethanes, while maintaining excellent performance properties. Product
#442 is also available in an ESD formulation which must be applied over
a base coat of Epoxy.com Conductive Epoxy.
EPOXY.COM PRODUCT #442 polyurethane provides a gloss finish. Product
#442 has good chemical, stain, and mar resistance. In addition, it’s easy to clean
and has excellent color retention under heavy foot traffic.
EPOXY.COM PRODUCT #442 is a high performance coating
for use in a variety of seamless floor and wall coating systems. Product
#442 eliminates the strong solvent odor normally associated with high
performance materials. It’s ideal for topcoats and finishes that require
high abrasion resistance. Typical application areas are clean rooms,
hospitals, pharmaceutical facilities, stained concrete, wood floors, and
as a seal coat for most Epoxy.com floor and wall
- Low VOC
- Low Odor
- Fast Cure
- Excellent Adhesion
- Excellent Abrasion Resistance
- Allow material to rest for 15-20 minutes for viscosity adjustment.
- Application rate is no less than 250-275 square feet per gallon. Thicker films will
show bubbling in the cured film.
EPOXY.COM PRODUCT #442 is a polyester resin/aliphatic polyisocyanate.
EPOXY.COM PRODUCT #442 is available in clear and pigmented colors. Gloss finish.
ESD formulation available in clear or pigmented.
Surface Preparation is the most critical portion of any successful resinous flooring
system application. All substrates must be properly prepared as outlined in Epoxy.com
Surface Preparation Procedures..
- Mix only that amount of material that can be used in a two hour period. In hot weather,
plan work for the cooler times of the day.
- If using less than full units, proportion the amounts carefully and mix for 2-3
minutes using a low speed drill, scraping the bottom and sides of the mixing vessel.
DO NOT ADD WATER.
- Apply Product #442 polyurethane at a spread rate of 275-300 square feet per gallon
to achieve 2.0-2.5 mils dry. Thicker application may result in bubbling in the cured
- Recoat time is approximately 10 hours at 77°F.
- Keep a wet edge at all times.
- Apply Product #442 ESD at a spread rate of 160 square feet per gallon to achieve
5 mils dry.
- Use with adequate ventilation.
- Read material safety data sheet before using.
|Mixing Ratio Clear
||4 Parts A to 1 Part B by Volume
|Solids Content Clear
||43%, by Volume
|Volatile Organic Content (VOC)
||1 ½ – 2 hrs. @ 77°F, 1 Quart45 minutes @ 95°F, 1 Quart
|Viscosity After 15 Minutes @ 77°F
|Viscosity After 30 Minutes @ 77°F
Wait 15-20 minutes after mixing to start application. Viscosity will decrease with time.
DO NOT ADD WATER.
|Gloss, 60˚ – Clear
1,000 gm. load,
|45 mg. loss
|Direct 160 in. lbs.
Reverse 160 in. lbs.
DRY TIME @ 77°F, 50% R.H.
|Dry to Touch
After completing the application of EPOXY.COM PRODUCT #442 Urethane Coating/Sealer, the installer should provide the owner with maintenance instructions.
EPOXY.COM PRODUCT #442 is easily cleaned with neutral soaps or detergents.
For more information visit http://www.epoxy.com, email me at email@example.com or contact Epoxy.com Technical Support Department at 352-533-2167
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Posted by Norm Lambert