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.

Know 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.

Tapcons are light-duty

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. While a Tapcon may be fine to hold down a condenser (that already wants to stay down), 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.

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 this).

Don't over-drill

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.

Clean 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, warble away.

Torque it down

Sorry, 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.

Don't overload it

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.

Related Tech Tips

Relative Humidity in the Supply Air Stream
When you first start checking your supply air with a thermo-hygrometer, you may notice that the relative humidity is REALLY HIGH. Often, the RH in a supply duct will be between 85% and 96% relative humidity on a system that is functioning as designed. The reason for this is fairly simple: In order for dehumidification […]
Read more
Like a Bull in a China Shop - An Oversizing Story
This article was written by Genry Garcia of Comfort Dynamics, Inc. Thanks, Genry! This is a piece about oversized air conditioners. Though the symptoms and consequences of oversized heating equipment are similar to those of air conditioners, you’ll notice that the focus throughout the article will be on the cooling side—specifically from the perspective of […]
Read more
The Ductless Dehumidification Conundrum
This tech tip was a COMMENT on a Facebook question about how ductless systems achieve some of their high-efficiency numbers at the expense of dehumidification. This was the question: Bryan Orr mentioned that multi-stage mini splits often do very little latent cooling (dehumidification) because on low speed the manufacturers all “let the evaporator float, which […]
Read more

2 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