repairing concrete with Epoxy

Acid Etching Revisited

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During my last blog on January 10, 2016 about “Surface Preparation When Installing Concrete” we discussed among other things preparation of concrete by acid etching. I want to revisit that now in a slightly less formal explanation about why it is not the best of the possible methods of doing surface preparation.

Acid etching does not remove most contamination from the concrete. It is necessary before you acid etch concrete to remove most typical type of contamination like oil, grease, paint, mastic, and a host of other things first.

Acid etching attacks the Portland Cement. The Portland cement is the “glue” that is holding your concrete together. So acid etching done incorrectly will do more damage than good. Even if you do it correctly your floor may not be as strong a substrate for epoxy (or anything else) than it would have been if you mechanically cleaned it.

If you are going to acid etch I suggest that you not only do it properly but follow it with abrasive cleaning, to remove the soft top part of your concrete that is damaged by the acid etching. When I was an installer of epoxy products I rarely if ever acid etched but instead did mechanical cleaning.

Here are some of the reasons acid etching may not be desirable for your job.

  1. Acid etching is a risk to safety. Acid can damage items at your jobsite and pose a risk of injury to the people in the area.
  2. Mechanical cleaning is better for the environment, no acid will find its way into the ecosystem.
  3. Mechanical cleaning allows quicker turnaround time, you don’t have to wait overnight for the substrate to dry.
  4. Mechanical cleaning gives you more consistently high quality substrate than acid etching does.

In summary, whenever you can use abrasive cleaning it is safer and better than acid etching.

Please email me your questions to norm@epoxy.com or visit our website at www.epoxy.com

Selecting the Right Floor for a Mechanical Room

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Mechanical Room Floors are very unique in their use and conditions. You have to consider the installation environment and the function of the floor. Our Mechanical Room Floor will protect the concrete, and contain any liquids that spill.

Systems used in mechanical rooms should be zero VOC. You do not want solvent evaporating from your material. Evaporated solvent could be picked up by your air handling unit sending it through your building. The best way to prevent this is with a VOC free 100% solids resin system. A resin system that is 100% solids has no solvent (or water) in it. It also means when you spread a gallon of material on your floor after it hardens you still have a gallon of material. With water-based and solvent based materials you lose half the material to evaporation.

Mechanical rooms should be chemical resistant. Typically they are top coated with Epoxy.com Product #2 Chemical Resistant Epoxy – www.epoxy.com/2.aspx. If it is a chemical feed room you can supply a list of chemicals and concentrations to the technical support department so you can make sure the #2 is chemical resistant enough.

The systems used for mechanical rooms are impact resistant. The limiting factor is the strength of the concrete substrate. Properly installed the epoxy will stay bonded to the concrete. The only way the epoxy can chip is if you chip the concrete from underneath the epoxy. You can install a thicker epoxy floor for an additional cost if you think you need still additional protection.

The systems recommend for mechanical rooms are highly abrasion resistant and will easily handle traffic up to heavy fork lift traffic. The system can be made even thicker if you have an unusual amount of abusive traffic.

When the mechanical room is over a finished space, it is suggested that a crack isolation membrane be integrated into the system. This can be done with Product #32 Epoxy Membrane System. The advantage of #32 Epoxy Membrane Resin as part of the system is 100% solids and has zero VOCs.

If the mechanical room is shut down and you can handle solvent and want something still more flexible you can use Epoxy.com Product #459 a two component, high solids, elastomeric urethane instead of or in addition to the Product #32 Epoxy Membrane above. Product #459 exhibits excellent elongation properties along with high tensile strength and tear resistance to make it an ideal crack resistant membrane for use under Product #2 and all of our other epoxy mechanical room floor coatings.

One of the primary reasons you need a mechanical room floor over finished space below is to waterproof it. The above methods accomplish the waterproofing in the center of the floor. The edges of the floor can be protective with a coving material up the wall and around pipe penetrations. That can be accomplished with Product #720 Epoxy Coving Resin System which can be used to install an integral cove base for all of our epoxy based mechanical room flooring and most of our other epoxy flooring and coating systems. This provides seamless wall to floor protection.

For more information on seamless water and chemical resistant mechanical room flooring, contact Epoxy.com Technical Support Department at 352-533-2167, or email me at norm@epoxy.com.

 

Waterproofing of Leaking Foundations

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This is the time of year when the ground thaws and basements leak. If you are one of those building owners, here are some earlier posts that you will find useful.

  1. http://news.epoxy.com/2014/09/04/epoxy-waterproof-block-wall-foundation/
  2. http://news.epoxy.com/2014/09/15/shows-how-to-identify-leaks-that-need-waterproofing-in-basement-walls-and-floors-that-are-made-out-of-poured-concrete-part-2b-will-deal-with-the-actual-repairs-to-poured-concrete-leaks/
  3. http://news.epoxy.com/2014/09/18/epoxy-injection-repairs-of-cracks-in-poured-concrete/

Poured Concrete Basement Waterproofing with Epoxy

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This is the second half of a 2 part of a series on basement waterproofing with epoxy. In Part 1, we discussed waterproofing block wall foundations with epoxy. In Part 2A we discuss how to identify leaks that need waterproofing in basement walls, and floors that are made out of poured concrete. In this part (2B) will deal with epoxy injection repairs of cracks in poured concrete, that cause the leaks.

Earlier we discussed how many homes and businesses experience leaky basements year after year. The worse time is in the spring and after heavy rain. We discussed prudent things that you can do to improve drainage against your foundation. Epoxy Injection is designed to waterproof and give you the concrete’s structural integrity back.

Why Epoxy Inject the Cracks?

We discussed in our last article that cracking is a sign of failure caused by stresses, inadequate design, improper curing, etc. One of the dangers of a structural crack is the effect that it has on the reinforcing bar. The reinforcing represents one of the main structural values of the concrete. Cracks left unprepared allow water to enter your basement and attack the rebar.

Epoxy injection resin has two purposes:

  1. It effectively seals the crack to prevent the damaging moisture entry. Second, it monolithically welds the structure together.
  2. The injection also stops the infiltration of water into your basement.

Epoxy Injection Port Setting

Clean the concrete on both sides of the crack being careful not to force concrete dust into the crack. Concrete dust can be detrimental to the injection processes in several ways. Vacuum the area completely with a shop vac.

You need to determine the spacing of ports to be set. The spacing is a factor of the tightness of the crack and the depth of the concrete substrate. Spacing is normally between four (4) and eight (8) inches.

Port Setting and Sealing

Align ports directly over cracks. That allows injection resin to flow into the crack. Seal surface cracks and the ports in place. Sealing the exterior of cracks is done with Epoxy Gel #2006.

Selecting the Right Epoxy Injection Resin

Epoxy injection resin should typically be low viscosity injection resin- Epoxy Injection Resin #301. It must be low viscosity resin so it will flow in the smallest hair line cracks. Resin can travel several feet from the point of injection. It may take some time before reaching the next port or penetrating through pin holes in the surface. Epoxy injection effectively fills cracks including small voids and hairline cracks

Pumping Epoxy Injection Resin

The most economical way to deliver the epoxy injection is with the 450 ml binary injection system, a manual gun, or the pneumatically driven one. This uses a binary caulking gun with static mix tubes to inject the resin, insuring continuously mixed fresh material.

Limit pressure, low pressures allow gradual resin flow into the crack for deeper penetration. Start injection at the lowest point, and continues upward on the crack area. While injecting the lowest port, resin will flow to and out of the next higher port.

When pure resin is flowing out the next port cap, plug the current injection port and move to the next port. Then injection continues in the port showing resin flow. This procedure continues until all ports are full.

CONCLUSION

Epoxy injection is very effective at repairing concrete cracks and cutting of water infiltration. The right resin and equipment is critical. Epoxy injection makes a crack watertight while restoring the original structural integrity intended for the concrete. You can get all of the material you need to do this by contacting us:

321-206-1833 Customer Service – Ordering and Order Status
Katey Fontaine, VP – Customer Service Director
sales@epoxy.com

Technical Support
352-533-2167
 Norm Lambert, President
Technical Support Director
info@epoxy.com

Additional Resources

http://www.epoxy.com/injection.aspx