Waterproofing of Leaking Foundations

May 4, 2015

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. https://news.epoxy.com/2014/09/04/epoxy-waterproof-block-wall-foundation/
  2. https://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. https://news.epoxy.com/2014/09/18/epoxy-injection-repairs-of-cracks-in-poured-concrete/

Applying New Epoxy over Old Epoxy

February 13, 2015

I frequently get calls and emails from folks who want to install our epoxy over an existing epoxy floor or coating that they have. They want to know if it is okay to go over it and what they have to do to properly prepare the surface.

If the existing epoxy is a good hard solid one that is well bonded to a well prepared substrate it is possible. On the other hand if you are replacing it, what is wrong with the existing epoxy? Has the existing epoxy been badly abused by heavy sharp objects being dragged on it? Was the exiting epoxy damaged by chemicals beyond the chemical resistance of the existing epoxy? Are you just trying to upgrade the look of the existing epoxy?

You should be concerned about going over epoxy that is coming loose from the substrate. That may mean that there was poor surface preparation. It may also mean that the quality of the epoxy might not be what it should be. You need to be concerned about epoxy that is wearing out. If it is wearing out you want to know why. My company and I personally started out as installers of epoxy. I have never seen or been made aware of any of Epoxy.com coatings and/or flooring systems that have worn out have come loose from the concrete. I have seen concrete so pounded by traffic that it came loose, but our epoxy was still attached and still doing its job. That is based on over 30 years of field experience with the products.

Back to the question, “can I put epoxy over epoxy?” I always assume that the reason that the epoxy is wearing out or coming loose is that the epoxy is low quality or the installation was poorly done or both until I can prove otherwise. The way that I do that is to attempt to grind or shot blast off the existing epoxy. If after a substantial effort the epoxy cannot be removed and I cannot hear a hollow sound under the existing epoxy, I feel I have proven that the existing material is solid and well bonded.

Let’s take a moment to discuss that dreaded hollow sound above. If the flooring system or coating is very poorly bonded you will get a sound from your grinder like you are dragging a piece of paper or a piece of stone under the grinder, or rubbing stone. When you tap it with a hammer you get a hollow higher pitch noise than you get when you tap solid concrete or a solid floor over concrete.

You must be sure that the substrate is free of all types of contamination, including but not limited to oil, grease, food fats, curing compounds, sealers, laitance, dirt, wax etc. The existing epoxy left behind must be well bonded, and sanded until it has no shine. See Epoxy Surface Preparation Procedures for more information on this subject.

The beauty of trying to get it off is you are removing all the shine and getting it ready to accept another layer of epoxy. Just before I install the new layer of epoxy I solvent wipe with xylene, let it dry. Then I recommend a coat either Epoxy.com Product #899 Primer or Epoxy.com Product #12 Chemical Resistant Primer. Then install epoxy as usual. For more surface preparation and installation tips please visit or “Where to Start” page at: http://www.epoxy.com/start/default.aspx

Related Resources on Epoxy

Where to Start” page may be the best way to get you off to a quick start.

Epoxy Coatings

Epoxy Primers and Sealers

Chemical Resistant Epoxy

Epoxy Chemical Resistance Chart


Epoxy.com Technical Support
Norm Lambert, President – Technical Support Director




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.

Basement Waterproofing with Epoxy Part 2A

September 15, 2014

Poured Concrete Foundation Waterproofing

This is number 2A of a 2 part series on basement repairs. In Part 1, we discussed waterproofing block wall foundations. In Part 2A 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.

In our last piece we discussed how 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.

Identifying the Source of the Basement Water Leak

The nice thing about poured concrete is that it holds water back very well. The leak typically happens at a cold joint or in a crack or hole in the concrete.

Concrete Cold Joints

Fresh (plastic) concrete doesn’t bond to hardened concrete. The exception is when a special epoxy bonding agent like Epoxy.com Product #2007 – is used (this bonding agent will be discussed in a future article). When concrete has hardened or has started to harden and you pour more concrete against it (without the right bonding agent) you get what is called a cold joint. These cold joints are a common source of water leaks.

Virtually all basements are built with a giant cold joint – the cold joint between the floor and the wall. Typically there is some sort of water-stops material installed in these joints intended to stop leaking at this cold joint. These water-stops can fail. So the wall to floor joint in a concrete basement is a frequent source of water leaks.

You can also get cold joints in the middle of concrete walls and floors due to multiple pours. You can get cold joints if concrete is setting to fast and fresh concrete is poured against semi cured concrete. Sometimes saw cuts in the floor can be a source of leaks

Form Ties

Then there are the ties that go through the concrete to hold the forms together on either side during the pour. If these form ties are not installed perfectly or if the concrete is not totally vibrated around them, these ties can act as a conduit to let the water in.


Wall and Floor Cracks

When concrete cures it shrinks that is called “plastic shrinkage”. That plastic shrinkage can and usually does result in the concrete cracking. These cracks are one of the easiest ways for water to get into your basement. If the water makes it to the fill side of the tank (under the floor or against the wall) it will typically leak out into your basement. You should look carefully for these cracks when looking for potential leaks into your basement. If you are able to investigate into the water infiltration into your basement when it is leaking it will be easy to see. If trying to find the source of leaks when the basement is dry you have to look for water marks on either side of the cracks and beneath the areas that might be leaking.

Repairing the Basement Leaks with Epoxy

In the next installment on this topic, I will deal with how you waterproof the cracks while structurally repairing them with epoxy and similar materials.

For more information please contact me:

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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