# Question on PPD practice exam - Historical building thresholds **URL:** \ **Category:** Project Planning & Design\ **Created:** [April 20, 2020, 2:11am UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038 "2020-04-20T02:11:02Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![rebeccacassidy33](https://blackspectacles.com/uploads/images/12.png) [@rebeccacassidy33](https://community.blackspectacles.com/u/rebeccacassidy33)\ **Post date:** [April 20, 2020, 2:11am UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038/1 "2020-04-20T02:11:02Z")
In a PPD practice exam case study, I was asked this question regarding an existing threshold in a historical building. **The original stone thresholds are 3/4” high. Which is the best solution for the treatment of the thresholds to make them ADA compliant?** This is what it said the correct answer was and why. _Replace the thresholds with new stone thresholds, that slope down to 1/4” max slope of 1:2_ _Correct. The threshold should have a slope of 1:2 to be compliant._ This is an image in the preservation briefs that were included as supporting materials. ![image](https://canada1.discourse-cdn.com/flex029/uploads/blackspectacles/original/1X/e58dab0dd9a523c06d4f3453c814427f813ec586.jpeg) Shouldn’t the slope be 1:12? Is the 1:2 a typo? The explanation does not give enough information on why it is correct if it is supposed to be 1:2. ---
**Author:** ![Lara](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.blackspectacles.com/lara/32/12_2.png) [@Lara](https://community.blackspectacles.com/u/Lara)\ **Post date:** [April 20, 2020, 2:16pm UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038/2 "2020-04-20T14:16:22Z")
Great question, and welcome to our ARE Community! @cat.heard9 or @heatherrivera are either of you able to help us out on this practice exam question? ---
**Author:** ![heatherrivera](https://blackspectacles.com/uploads/images/23.png) [@heatherrivera](https://community.blackspectacles.com/u/heatherrivera)\ **Post date:** [April 20, 2020, 6:50pm UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038/3 "2020-04-20T18:50:52Z")
I believe what the question is getting at is knowledge and compliance of IBC 2015 1010.1.7 Thresholds. This states that raised thresholds greater than 1/4" must be beveled with a slope no greater than 1:2. You can have 3/4" threshold, but since it is over 1/4" in height, the beveling must happen. So to your original question, 1:2 is correct for a threshold. 1:12 is a ramp. It’s certainly tricky; and I’m not entirely sure what the graphic is portraying without reviewing all of the supplemental reference material, but I hope the above explanation helps. This is certainly something that is a great differentiation to know for the exam. Keep up the awesome work! ---
**Author:** ![rebeccacassidy33](https://blackspectacles.com/uploads/images/12.png) [@rebeccacassidy33](https://community.blackspectacles.com/u/rebeccacassidy33)\ **Post date:** [April 20, 2020, 8:19pm UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038/4 "2020-04-20T20:19:51Z")
Thank you. I was able to find that in the IBC. Since the question had “ADA compliant”, I wanted to make sure the same was true in the 2010 ADA standards and I did find more supporting information. _404.2.5 Thresholds._ _Thresholds, if provided at doorways, shall be ½ inch (13 mm) high maximum. Raised thresholds and changes in level at doorways shall comply with 302 and 303._ _**EXCEPTION: Existing or altered thresholds ¾ inch (19 mm) high maximum that have a beveled edge on each side with a slope not steeper than 1:2** shall not be required to comply with 404.2.5_ ---
**Author:** ![heatherrivera](https://blackspectacles.com/uploads/images/23.png) [@heatherrivera](https://community.blackspectacles.com/u/heatherrivera)\ **Post date:** [April 20, 2020, 10:50pm UTC](https://community.blackspectacles.com/t/question-on-ppd-practice-exam-historical-building-thresholds/1038/5 "2020-04-20T22:50:27Z")
Nice find! Those existing buildings always give you a bit more leniency. A bit - like 1/4".