Locate centre of studs from over the top of weatherboards

Forums › Home Workshop DIY › Locate centre of studs from over the top of weatherboards

E3xtc

754 posts

Ultimate Geek

#265823 13-Feb-2020 07:57

Hello,

I have a bit of a weird situation where i need to know (with reasonable certainty) the centre point of studs in the walls, located from outside the house (ie through cedar weatherboards, not just over plaster board). I realise i can see the nail locations holding the weatherboards on, but I need to know if that is in the centre of the stud or not (there is no way to tell if the nails are offset to one side or the other)

I was hoping a decent stud finder would be my saving grace, but I am keen to hear peoples thoughts/experience/recommendation on them.

Thanks

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1940 posts

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#2417320 13-Feb-2020 13:30

I can’t see that a stud finder would be of any use outside, you can already see the nails.

There may be the odd clout inside on the building paper but there is no guarantee they are in the centre of the stud either.

In theory you should have around 20 mils either side of the nail, I am curious as to why you need the exact centre.

Sharesies

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E3xtc

754 posts

Ultimate Geek

#2417323 13-Feb-2020 13:33

Just want to be 100% sure. I am going to be putting some coach screws in to hang some L brackets off, which will be used when maintaining the house (on this largely inaccessible 8-10m high wall) and I just want to be 100% sure that the screw is going into the centre and not at the side/edge of the stud.

Lastman

306 posts

Ultimate Geek

#2417329 13-Feb-2020 13:38

Stud finder. On a coldish morning, if the walls are insulated you’ll see (often quite a neat) outline of the studs as they have no condensation on them. If the walls aren’t insulated it can be the other way around.

wellygary

7387 posts

Uber Geek

#2417334 13-Feb-2020 13:43

To be honest the only way you are going to be 100% certain is to take off a board just below where you want to put you coach screws in..

.. which is not impossible

mattwnz

19389 posts

Uber Geek

#2417335 13-Feb-2020 13:45

Brunzy: I can’t see that a stud finder would be of any use outside, you can already see the nails.

There may be the odd clout inside on the building paper but there is no guarantee they are in the centre of the stud either.

In theory you should have around 20 mils either side of the nail, I am curious as to why you need the exact centre.

Depends if they are horizontal or vertical weatherboards, as vertical ones are usually nailed into the dwangs, not the studs. A stud finder may help, some do deep scans.

Clima

127 posts

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Lifetime subscriber

#2417351 13-Feb-2020 13:52

You could drill small holes to locate the edges of the stud where you want to put the screw.

tripper1000

1543 posts

Uber Geek

#2417390 13-Feb-2020 14:11

Clima: You could drill small holes to locate the edges of the stud where you want to put the screw.

This is about the only accurate way to find the centres. Have done it myself using a 1.5mm drill.

Most stud finders do not have the resolution you want.

1.5mm hole is much easier to patch up than a 5 or 6mm hole so I'll always start any screw-hole in the wall with a 1.5mm test hole in case of missing the stud.

Make sure you weather seal those holes good. Found major rot in some studs of my house because someone put in coach bolts and let the water into the wall :-(

duckDecoy

795 posts

Ultimate Geek

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#2417402 13-Feb-2020 14:31

tripper1000:

Make sure you weather seal those holes good. Found major rot in some studs of my house because someone put in coach bolts and let the water into the wall :-(

How would you recommend doing this?

Brunzy

1940 posts

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#2417424 13-Feb-2020 15:05

I wouldn’t drill holes if I didn’t have to,
Why don’t you drill a hole in line with the nail with the smallest drill bit you have , if it goes straight in , all good.You could then drill in the same hole at an angle, R & L and see which side gets through first.
Then you would have a family good idea of the centre.

Fred99

13684 posts

Uber Geek

#2417446 13-Feb-2020 15:32

If it's any use to you, I just tried a Zircon brand edge finding studsensor (model L50) which IIRC isn't top of the line gear - $60 at mitre 10.

Tried it on "deep scan" setting on some 19mm hardwood planking with gaps - so I could see the joists clearly. It was much more accurate than I expected - would pick up the edge about a few mm wider than actual position both sides, if you dropped a pencil mark on each edge detected and went 1/2 way, it would have been spot on.

OTOH I had a go with some linea weatherboard over battens and it was completely useless on "deep scan" setting, but seemed to be working fine on "stud scan" setting (but I didn't drill holes to check).

Bung

5445 posts

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#2417451 13-Feb-2020 15:40

The trouble with small drill bits is that they are probably too short. You might have to improvise with a bit of coat hanger or bicycle spoke to get through cedar and stud on an angle.

8 to 10m is high up. I hope you've thought about getting there.

Loismustdye

887 posts

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#2417482 13-Feb-2020 16:32

Fred99:
If it's any use to you, I just tried a Zircon brand edge finding studsensor (model L50) which IIRC isn't top of the line gear - $60 at mitre 10.

Tried it on "deep scan" setting on some 19mm hardwood planking with gaps - so I could see the joists clearly. It was much more accurate than I expected - would pick up the edge about a few mm wider than actual position both sides, if you dropped a pencil mark on each edge detected and went 1/2 way, it would have been spot on.

OTOH I had a go with some linea weatherboard over battens and it was completely useless on "deep scan" setting, but seemed to be working fine on "stud scan" setting (but I didn't drill holes to check).

That’s interesting, im trying to do the same over lines weatherboard land having zero luck with my exisiting stud finder, might see if I can hit someone down with that model and see if it works out for me.

SomeoneSomewhere

1127 posts

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#2418593 13-Feb-2020 21:01

Thermal imaging gear can also be really good if there's a big temperature differential between inside and outside.

mclean

578 posts

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#2420762 14-Feb-2020 10:16

If it's a newer house (with the boards fixed over a drained cavity) you should be able to find the exact edges of the cavity batten by sliding something thin (like a spatula) up the crack between the boards. This won't work on an older house with direct-fixed boards - the paper will be in the way.

E3xtc

754 posts

Ultimate Geek

#2420765 14-Feb-2020 10:25

Oooh this could be interesting. The house is about 10 years old...is that "newer" enough?

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