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How to identify services behind a wall before drilling?

I'm planning to setup three flexi-storage wall strips over this laundry wall to create some shelf and hanging racks, etc.

The main concern is the power lines and water lines behind. I have tried multiple stud finders, a magnet hung from thread and what not, to try and trace where the lines go but it has been extremely hard.

What is the best way to approach this? My intention is even if I don't DIY this - I hope to at least learn a thing or two about possible wiring/water lines configuration in general. Thanks,

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EricL

Hello @kvenkate

Welcome to the Bunnings Workshop community. It's sensational to have you join us and thanks for sharing your question about drilling into your laundry wall.

Its ok to be nervous when drilling blindly into drywall. But you can take away this nervousness by arming yourself with information. I suggest having a look at this guide - How to use a stud finder. The stud finder that was used for the guide is the Ryobi Stud Finder with AC Detection RYSF5003. It detects metal, timber and live electrical wires, plus it has auto-calibration and auto-depth scan technology that enables scans up to 38mm deep. It also has a built-in stud marker for marking out the centre of studs.

If you are looking for a stud finder with a few extra features, this is the one to add to your D.I.Y tool collection. I've had mine for a few years now and it has not let me down. By marking the position of the electrical and plumbing facilities you should be able to drill confidently into your wall. My best advice, scan more than twice! There is nothing wrong with triple checking the position of the studs and wires in your wall.

Once you've determined the position of all the items in the wall, I would still encourage you to do a test with hammer and nail just to be sure you are drilling into the correct spot. By using this method you'll also be able to tell if you have timber or steel studs.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

Dave-1

Afternoon @kvenkate

🙂 The eternal "wish I had exray eyes" question, So many times Ive wanted to see what is behind the plaster. Like you, I havnt had a lot of luck with stud finders (I do admit the ones I have used are on the cheaper side) There are a few things I do to help me find the studs tho.

Measurements, once you have found one then it helps you find others. They are a set distance apart, 450mm is the standard.

Lines of easy-ness 🙂 yep that really helps routing cables and also pipes. Generally the power will be in straight lines and also wont be hard up against the inside of the plaster, vertically or horizontaly. So I add caution in my mind along those lines (straight down or up for a power point is how cabling may run.

Waterpipes will generally go straight down in a vertical profile. And probarly wont be hard up against the plaster.

Also Note that power points and waterpipes may be mounted on noggins or studs to give them ridgidity. If you sketch out in a note book your blank wall and find one of the above, then you can fill in the other areas like a jigsaw puzzle.

For instance with your pic.

We know that there will be two studs at either corner of your wall.

I suspect the power point may hang off a nogin.

The three taps will be fixed to a nogin as well. And wont be spanned across a vertical stud. (unlikely)

So Im starting to think that there may be a stud on the right of the power point and the left of the most left tap.

Tapping the wall with a screwdriver handle will help narrow down the location as well. Id start about 500mm above the power point were I suspect the stud to be and work may way back and fourth and listen to the change in timbre of sound. There will be less things to "find" as you are above all the extra noggins) so you should be able to find the second stud to the right. Sketch it on your notepad 🙂 You can confirm it is a stud/nogin by tapping a 50mm bullet head nail through the plaster, yeah it will leave a mark if its wrong but it will provide proof at least.

By a process of elimination you should be able to work out whats inside the walls 🙂

Dave

Nailbag

Hi @kvenkate

What @Dave-1 is describing is basically what the graphic below is providing as a rough idea on how it might look internally. The electrical cable/s in red could be run in several ways, but the water pipes will be highlighly likely running straight down. Slighter chance off to the left and unlikely from above but possible.

The stud finder @EricL I can vouch works very well, but can still be a bit hit and miss on actual width of the stud. For my purposes I have a very accurate one, but it's double the price. But I wouldn't go to that expense. So, to confirm the location and actual width of each stud which will be either 35mm or 45mm thick. I would use the Dave method of tapping in a small 30mm brad in to the wall along the line that would be covered by one of the shelves. Don't worry if its starts to look like Swiss, cheese, nobody will ever see them. If the brad goes through easily you have hit dead space. If it strikes something solid you have hit a stud. Tapping in either side will find the width.

This will be a safe method to find the studs/noggins without fear of damaging any services. Just tap the brad in lightly. the plaster board is only 10mm thick. And when drilling holes, go slow and don't apply t0o much pressure. Your only drilling pilot holes to make the shelving fixing screws go in easier.

Nailbag

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kvenkate

Thank you so much mate, @Dave-1 ! Appreciate the detailed explanation. I hope to get back this piece of work over the long weekend. Feeling more confident now, cheers.

kvenkate

Thank, legend! @Nailbag The picture is super helpful. Def feeling more confident now. Cheers,

kvenkate

Thanks @EricL . Super helpful. I actually use the same stud finder from Ryobi. While it's pretty good with studs, it's AC detection is just always on for some reason. I've tried placing the other hand on the wall and what not, but no luck. I've tried two stud finders now (got the first one replaced thinking it was faulty) but been having the same experience. It is just always on Red - detecting AC. I read online that this could be because of the type of insulation behind the wall. Thoughts?

Nailbag

Hi @kvenkate

Dense insulation will cause even some of the pro detectors to not be able to differentiate where the studs are because there are no defined cavities between. But as far as effecting electrical cables, that I have not heard of. Have you tried turning the mains power off to see if that makes any difference? The other cause, but less likely on an internal wall is foil insulation, which is often what is the cause of a constant metal/electrical pickup.

If the detector is finding the studs, ignore the electrical detection if it's on constantly. The difference between stud finders is how accurate they are at depth. The cheaper they are the less depth they can scan. Mine scans studs to just over 40mm with extreme accuracy to each edge but doesn't do metal or electric cables as I can sort myself around that. That Ryobi one states 38mm but doesn't have the same tech for accuracy. But does the job good enough for occasional use.

Nailbag

JacobZ

Hi @kvenkate,

Insulation can certainly affect the AC detection in your stud finder, especially if there is foil-backed insulation. These materials may reflect signals or create an environment where the stud finder perceives an AC field.

Nearby electrical devices, such as lights, power outlets, or even large appliances, can also create electromagnetic interference that keeps the AC detector active. Turn off any nearby circuits to see if it resolves the issue.

Let me know what you think and if you have further questions please don't hesitate to ask.

Jacob

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