Hello. We're very sorry to hear of your experience with your StudSensor™ HD70. There are enough variables in wall construction (insulation properties, moisture issues, general inconsistencies, etc. etc.) that we would have to do some trouble shooting with you to figure out why your HD70 is registering the whole wall as a stud like you describe. It’s a really great tool. We’re positive we can help you out. Please contact us through the Zircon website. Thank you.