Hey, Where Did Those Detectable Warnings for Truncated Domes Go?

Bumps, turtles, and a colorful variety of other terms have been used when referring to detectable warnings for truncated domes.  When speaking to people familiar with the Americans with Disabilities Act (ADA) often times they understand the acts intent, but not the details.  The devil is usually in the details and this is no exception.  In the field of detectable warnings there is a variety of materials, applications and installation options available.  With all of these options, the waters have become murky between innovators and imitators.  Let’s get some basics about detectable warnings for truncated domes requirements out of the way.

detectable warnings for truncated domes

Individual detectable warnings for truncated domes are measured at the base, top and in height. 

• The dome base diameter is to be between .9” and 1.4”.
• Dome tops are to have a minimum of 50% and maximum of 65% of the base diameter.
• Height requirements for each dome are exact at .2”.

Detectable warnings for truncated domes spacing is measured in two ways, center to center and base to base.

• Two adjacent domes measured from center to center must be a minimum of 1.6” and maximum of 2.4” apart. 
• Base to base the spacing must be .65”.

These requirements that the ADA has set forth are specific and require adherence to remain ADA compliant.  What we see frequently is the tile installed and it looks okay, but within a years time it looks as though we should have been counting in dog years.  The issue with the majority of all these manufacturing materials (specifically, rubber, concrete and brick) is their deterioration rate.  This is exhibited by detectable warnings for truncated domes being chipped, broken, and or completely removed.  These materials are also notorious for premature discoloration.  If your inspector is made aware of these issues it can be a costly mistake for the contractor and other end users, if they want to remain within ADA compliance.

In these swampy waters we have seen one alpha male emerge, a stainless steel manufacturer of detectable warnings for truncated domes named Advantage Tactile Systems, Inc. (www.advantagetactile.com).  They offer a 16 gauge tile, with stamped in truncated domes and an exclusive, “duragrip finish” for color compliance.  In addition to all of these features they back up this wonderful product with a 10 year warranty.  The combination of these benefits makes the detectable warnings for truncated domes the most durable and cost effective product available. 

By Shawn Osborne