Common Concrete Anchor Fails

No matter what trade you work in, you will need to use a concrete anchor at one time or another. Here are some mistakes I have seen (and made) that you will want to avoid:

Not knowing your concrete

Is it a concrete block hollow cell? Poured cell? Concrete slab? What is the PSI? Not all anchors are created equal for every type of concrete. Make sure you know exactly what you are fastening into and choose the right anchor.

Using Tapcons for heavy-duty anchorage

First off, “Tapcon” is just a brand name for a type of screw-in concrete anchor, so take the name with a grain of salt.

Your typical threaded “Tapcon” is for light-duty tasks. A Tapcon may be fine to hold down a condenser (that already wants to stay down). However, it would probably (definitely) be the wrong option for mounting a heavy motor assembly to the wall. For big jobs, go with a tougher anchor.

Hint: If it has threads and you “screw” it in, it probably isn't the toughest option.

Anchors embedded too shallow

Most concrete anchors have a minimum embedment depth. You can usually embed deeper, but you need to hit the minimum at least. Read the directions to see what the minimum depth should be.

Keeping the anchors too close

All anchors have a minimum distance they can be from one another. If you get them too close, the whole kitten kaboodle can pull right out on you. (I've done that.)


Wedge anchors (Red Heads) are common heavy-duty anchors. When drilling the hole, wrap electrical tape on your bit at the depth you want to go so that you don't over-drill the hole—or worse, blow out the other side.

Not cleaning the hole

With a wedge anchor, the dust in the hole can act like a lubricant, making it easier for it to pull out. When done drilling, use a round bottle brush or vacuum to clean the holes out. This is especially true when using an epoxy “chemical” bolt.

Warbling the bit

With concrete anchors, use the right size bit and run it straight. Don't be warbling the bit around—unless your desired result is having the anchor pull out and destroy a monastery. In that case, you can warble away.

Not torquing it down

Sorry, but you really do need a torque wrench, especially if you are working with large wedge anchors. Torque that sucker down to factory specs, and you won't need to worry.

Remember, you may want to retorque it after it's been put under load a few times, especially in safety-critical applications.

Overloading the anchor

Before you get started, make sure you know the ft/lbs of force the anchor will be under. Play on the safe side. As GI Joe says, “Now you know, and knowing is just scratching the surface.”



P.S. – You can watch a video on wedge anchors HERE.

P.P.S. – The 3D renderings came from a complete residential HVAC condenser installation guide on our YouTube channel, which you can watch HERE. The part about using anchors is about 27 minutes in.

Related Tech Tips

Careful With That 40VA Transformer
A 40VA transformer is rated for 40 VA or volt-amps on the secondary. For a typical 24 volt secondary, this is simply using Watt's law to calculate amperage. (For more information on Watt's or Ohm's laws, please check out this article HERE.) 40 ÷ 24 = 1.666666 ∞ (round up to 1.67 already) So, you […]
Read more
Pool Heat Pumps, The Basics
Note: My brother Nathan wrote this a few years back, and I only did some minor editing. A pool heat pump is essentially a water-cooled air conditioner in reverse. It usually has a large air evaporator on the outside that looks like a condenser coil and a heat exchanger (usually tube-in-tube) on the inside. A […]
Read more
Cleaning Condenser Coils Still Matters
There was a story that came out recently based on an ASHRAE study performed by David Yuill from the University of Nebraska. The study appeared to indicate that condenser coil cleanliness makes no difference on system performance and efficiency. Those of us who have worked in the field know that coil cleaning matters because most […]
Read more

3 responses to “Common Concrete Anchor Fails”

  1. how can i view the all video that you posted? please let me know thanks and more power.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.


To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from