Mitigation of Concrete Slab Chemical Vapors

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.

Background

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

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

Epoxy Mortar Installation

June 19, 2019

Epoxy.com Mortar Systems can be used to make permanent repairs that no other kind of product can make. The purpose of this blog is to give you an overview of what you can use and how to use it.

  1. Product Selection –  The following are a list of Epoxy.com Products that make excellent epoxy mortars  All the products listed below are zero (0) VOC, so it meets even the strictest low VOC requirements, and meets Indoor Environmental Quality/Air Quality (LEED IEQ 4.2 Indoor Emitting Materials Credit). See the individual product component technical data sheets and MSDS for further information.
  2. INSTALLATION:
    • First and foremost is good surface preparation.  Good surface preparation is necessary for most if not all patches to have long term success: www.epoxy.com/surfaceprep.aspx.
    • Prime the bottom of the whole with some of the neat mortar resin. Neat mortar resin is the liquid (A&B) mixed at the proper mix ratio and stirring in a way to insure a completely mixed product.  This will typically take about 3 minutes.
    • Mix some of the neat epoxy into the Epoxy.com Mortar Blend Aggregate #82 or other appropriate dry clean silica sand gradation.
    • The amount of sand aggregate depends on the aggregate used. 
      • Typically, the Epoxy.com Product #82 Mortar aggregate can be added at a rate of 18 to 27 lbs. of #82 per 1.5 Qt of mixed resin (1Quart of A to ½ Quart of B).
      • You will need to recalculate the sand above when using a different sized batch. This is doubly true if using one of or 4:1 mix ratio material.
      • Shallow patches tend to be a smaller amount of sand filler.
      • Deeper patches tend to be on the higher side.
      • If you get a lot of resin to the surface your mix is too wet.  If your mixture after it hardens is porous, or weak then you have added too much aggregate.
      • For a better finish in very deep pours do it in 2 lifts. 
        • Fill all but the last ¼ inch plus or minus with your dryer mix. Allow to cure hard (typically overnight).Fill with a wetter mix on top of that after the first one has cured.
        • To ensure proper adhesion between layers never wait more than 24 hours between layers.
      • It is always better to have your patch slightly higher rather than to low.  If you are slightly high you can grind the patch back to level. If to low you will need to fill again. 
    • For very shallow fills (1/32 or so) where the sand particles are to large you can use any of the following:

As always, when in doubt contact me at Epoxy.com Technical Support with your questions.

norm@epoxy.com
1-352-533-2167

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Posted by Norm Lambert

Epoxy Cold Temperature

January 29, 2015

Installing Epoxy in Coolers and Cold Temperature

Extend Epoxy Installation Season into Winter

I have spoken on this subject here before but this time of year I get a lot of calls and emails about installing epoxy in cold temperatures. Our company started out as an installation company in Vermont. Summers are very short and winters are very long in Vermont. To stay a viable company, we had to figure ways of working through the winter.

Tenting and heating areas during the winter is time consuming and expensive. The solution is found in resin products that will set in low temperatures. The most durable and cost effective options of installation at cold temperatures is Epoxy and Methyl Methacrylate.

Cold Temperature Cure Resins can also be used as a super-fast setting Resinous Mortar or Coating at normal temperatures. Our Cold Temperature Cure Resins used at normal temperature give you quick turnaround time for small jobs, or larger jobs that require a short turn-around time.

Cold Temperatures Epoxies

Cold Temperature Cure Epoxy Resins allow installation to be done at low temperatures as low as 35°F., expanding your epoxy coating and epoxy flooring installation season. Epoxy.com Cold Temperature Cure Epoxy Resins can also be used in cold storage areas like food processing areas, where the temperature cannot be raised higher than 35° F or so. Normal cured epoxy typically requires 50°F or more.

Depending on how you mix the aggregate into the products below, they can be used as a mortar for overlays, or a grout for sealing between other hardened construction materials.

Commonly Used Cold Temperature epoxies

Product #1 Cold Temperature Cure Epoxy Coating is 100% solids and specially formulated coatings for cold temperature applications. Cold Temperature Epoxy Coating #1 is able to cure at temperatures as low as 35°F. It is has Zero (0) VOCs. Since it has no VOCs, it has no solvent so it meets the strictest possible standard for a low VOC coating. It is often used in coolers and food preparation areas that require constant low temperatures. Product #1 Cold Temperature Cure Epoxy Coating is also frequently used in room temperature applications to meet super-fast cure, limited shutdown needs.

Product #10 Cold Temperature Curing Epoxy Mortar Resin – This product has a low modulus of elasticity (flexibility) and is Low Viscosity. The low viscosity allows heavy loading of the right fillers. The heavy filler loading helps not only to save money, but helps to maintain better thermal coefficient with respect to concrete and steel. The low modulus of elasticity prevents it from being brittle making it less vulnerable to thermal coefficient differences. It also gives it better impact resistance.

You can find more information on cold temperature cured epoxy at: http://www.epoxy.com/EpoxyColdCured.aspx.

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Posted by Norm Lambert

Basement Waterproofing with Epoxy

September 4, 2014

Many homes and businesses experience leaky basements year after year. The worse time is in the spring after winter accumulation of snow. There are a number of prudent things that you can do to improve drainage against your foundation like roof gutters, grading and improvement of drainage. The recommendations here do not replace that conventional wisdom. It is designed to augment and improve upon these conventional methods.

The following article will be 1 of 2. This one deals with Block wall foundations. The next one will deal with poured wall foundations.

Waterproofing Block Wall Foundations with Epoxy

One of the nicest features of most of our epoxies are that they are virtually 100% waterproof. Water simply cannot pass through a good healthy layer of properly applied concrete, block, wood etc. Epoxy also has an incredible bond to concrete, cement, wood and many other construction materials. The bond strength of epoxy to concrete and cement is greater than the tensile strength of the concrete. That means on properly prepared concrete, epoxy cannot be removed without pulling concrete with it. The same is true about wood.

Considerations in Waterproofing with Epoxy

All this gives you the perfect combination to make a block wall watertight. There are limitations however:

  1. In an ideal world the epoxy should be applied on the positive pressure side of the wall, the outside. This way the pressure of the water is pushing it into the wall. That helps to mitigate the likelihood that you get so much pressure on the concrete block that you fracture the block. Typically by the time you know you have a leak you are already backfilled and landscaped so 95% of the time it is not practical to do on the outside of the wall. So you do it on the inside instead.

    Water exerts a pressure of less than ½ psi per foot of water depth and most basement walls are only 8 foot high, so you would typically only see 4 psi. So it is unlikely that you have a pressure greater than the tensile strength of the block. So doing it on the inside is typically the only economical alternative.

  2. The Product #1W Epoxy is much more flexible than the concrete block and mortar, but if the mortar or concrete gets any significant cracks in it, it will crack through the coating. On the other hand, the system is very easy to patch if it does crack. We also make a wall grade version of our crack isolation membrane Epoxy.com Product #32 – www.epoxy.com/32.htm – which can reduce the potential for small cracks (which are the most common).
  3. A clean substrate is required for maximum effectiveness – www.epoxy.com/surfaceprep.aspx. For technical support contact me at norm@epoxy.com or 352-533-2167

Installation of Epoxy Waterproofing on Block Walls

Once the wall is clean, you need to point-up (fill) any cracks, bad mortar joints, and larger holes that are in the block. Some people use conventional mortar and wait 28 days for it to cure as per the American Concrete Institute. This is a very inexpensive way to do it, but can be affective if done properly. A more effective way to insure the right results is the use of Product #2005 Epoxy Gel Adhesive – www.epoxy.com/2005.aspx. That insures that you have a tight bond over the cracked areas and have already produced a tight waterproof seal in that area. Also the #2005 Gel Epoxy is semi flexible and allows more movement before cracking that conventional grout. The #2005 allows your coating to be installed the day after the #2005 is applied.

Once the cracks and holes are repaired, much of your work is done. You simply apply 1 coat of Epoxy.com Product #899 – www.epoxy.com/899.aspx – Epoxy Primer and allow to dry overnight.

After the primer has cured overnight you can apply the optional crack isolation membrane Product #32W – Wall Grade, or proceed to the coating below. If you do apply the crack isolation membrane 2 coats of the membrane are best. One advantage of the two coats of membrane is that typically you can reduce the number of coats of top coating that is required to seal the block. As you put on the membrane be sure to check to see that the holes in the block are being filled as you go.

Depending on the porosity of your concrete and if you used the crack isolation membrane above you will want to apply 2-4 coats of 1W epoxy wall coating. As you put on each coat check to see that the holes in the block wall are being filled.

Summary of Waterproofing Basement Walls with Epoxy

In conclusion: Leaking basements are a major problem to many structures in the spring. The easiest time to repair them is during the winter when there is little or no leakage. Epoxy.com epoxy coating systems can affectively and economically solve most basement leaking problems. The final product is a hard attractive ceramic like finish that does not require additional painting or other finishes over it.

Next Issue: Waterproofing Poured Wall foundations with Epoxy.

Additional Information on Epoxy Coatings

Product #1W (Wall Grade)  Epoxy Wall Coating – a general purpose epoxy wall coating

Product #2W (Wall Grade) Cemical Resistant Epoxy Wall Coating 

Product #32 (Wall Grade) Flexible Epoxy Membrane

Where to Start when installing epoxy.

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Posted by Norm Lambert

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