Joist hell!

[LianneM85]

Looking for some advice on finding the ceiling joists in my living room. I have tried to use an electronic stud finder but it seems inconsistent. I have also tried the knocking method with my knuckles and also a hammer, but not hearing much of a difference in the sound.
I've read that you can use magnets and where they stick is where the plasterboard is screwed/nailed to the joist. After running a magnet over the ceiling for a long time it stuck in one place so decided to get a stronger magnet. I bought a magnet tool which is meant to pick up metal items you drop (up to 2kg apparently), however when I run it over the ceiling it actually repels itself from the ceiling (including the spot where the small magnet would stick. I tried putting a thin screwdriver through where I believe a joist is, after going through the plasterboard it hits something solid which I believe is wood, however if I push it, it lifts up. Should joists have any movement? If so how much? Any other advice or do I have to admit defeat and get someone in to help. Any advice gratefully received thanks

 

[Burnerman]

I guess you have just found some timber rubbish or whatever in your ceiling void - joists don't have any movement.
Unfortunately I don't think a magnetic probe would be much use either. Are you trying to find just one joist, or all of them?
John

 

[LianneM85]

Ok thanks. Just need to find 2 as I'm trying to put up a dance pole and you tighten it so the pressure between the joists and floor hold it up. I also have a piece of wood to go underneath the ceiling to dome to help distribute the pressure more.......assuming I find the joists!

 

[Burnerman]

Just as a kick off, do you know the orientation of the joists within the ceiling?
One trick - minimal damage - is to drill a 3mm hole into the void, and pass a length of wire (straightened coat hanger, maybe) which has a 90 degree bend in it through the hole. Twiddle it, and it should bump up against a joist.
You will need a good fixing for the pole, I guess so its worth persevering. Is there any possibility of lifting a floorboard from the room above?
John

 

[LianneM85]

Going on what I've read, as you walk in the room they would go straight ahead and not left to right, but I'm basing this on that I read they tend to run the shortest length of the room and also there is a thin crack right along the plasterboard in the centre of the room which potentially means it's on or next to a beam?
I could lift the floorboards I guess as the upstairs is a converted loft but only used for storage. Does the fact that its attic space change anything?

 

[Burnerman]

If you peek into the loft, the joists will run in the same direction as the roof rafters.....across the house, if you like. That's probably the most important thing to ascertain here.
Then, if you measure the distance between the joists you'll find its the same - great for defining the joist centre which is where you want the pole screws to go. If you can guess where you want the pole to be approximately, a few small drill holes along side the joist from above will give you their position from below - maybe easier if you poke some lengths of wire through too!
John

 

[DaveHerns]

If this is for pole dancing do you think this type of fitting will be strong enough?

 

[mattylad]

Can you take the floorboards upstairs up?
You only need to do it at one edge of the room.

 

[KenGMac]

LianneM85, Hi.

I regularly use a small very bright torch? how?

If you have a Plasterboard ceiling?

Using a small LED torch, a Led-Lenser or similar which has a very bright light, I place the torch parallel to the surface but just a little away from the surface so that the beam of the torch is washing across the surface of the plasterboard, a small amount of adjustment in how far you keep the light away from the surface will be needed.

What I then look for are the indentations caused by the filled nail or screw holes, these minute imperfections, such as filled nail or screw holes tend to be easy to spot, I also use a magnet, but the torch method works for me, it appears that no matter how much polishing the plasterer does on the final skim. the depressions caused by the nails or screws do show up using this method?

if you try the torch, but It has to be a very bright beam, please let the board know the outcome?

Cheers.

Ken.

 

[LianneM85]

Dave - It's more pole fitness, strength training, than dancing, so less swinging about but the fitting is used by lots of people. I've used them before and they are very sturdy. I think it is better to have them under 2 joists rather than 1 tho. Also the ceiling dome is round so I have a square piece of wood to go underneath to help distribute the weight more and protect the ceiling. Not sure what the fitting is called but you tighten it with an alan key until it's rigid if that makes sense.
Ken - I did try the torch method but probably wasn't bright enough as no luck.
My next mission is to get the floorboards up! A corner of the room has had the carpet lifted (was used for a large animal tank by previous occupant) so I lifted the wooden covering on this patch. The floorboards are old looking and have been nailed in with what looks like a square headed nail? Tried loosening the board off with a hammer and fairly thick knife........resulting in half a knife! Assuming a chisel or crowbar is needed?

 

[Burnerman]

Thats a typical flooring nail you have.....you'll need a wrecking bar tool to gently prise the boards up......lift one that has been moved before if you can as they are easy to damage!
If you need to saw the floorboards, just remember you don't know whats below, pipe and cable wise.
John

 

[LianneM85]

Oh Showing my complete DIY ignorance there. I think if it gets to the point of cutting the floorboards I'm going to have to admit defeat and get some help

 

[bernardgreen]

The nails in the floor boards will tell you where the joists are under the floor boards. A knife ( even a broken one ) slid in the gap between boards will tell you exactly where the joist are in the place you want to fit the pole. You then need to get that information down to the under side of the ceiling where the pole is going to be fixed.

Drill a small hole in the floor board next to the joint and push a thin metal rod with a sharp end down through the hole and bore through the ceiling. A straightened metal coat hanger with a sharpened end will do the job. Or if the rod is magnetic then while one person holds the rod with sensitive fingers another person moves a magnet long the ceiling until the rod is felt to move. The magnet is then vey close to the joist.

 

[DaveHerns]

I'd be happier if it was firmly screwed top and bottom rather than just held in by pressure. I've had shower rails that are spring loaded to fit between 2 walls and they're OK till they fall down. Plus you'll mark the ceiling if you adjust the allen key tightly

 

[Cgas]

The magnets do work we use it all the time for reboarding and it's usually boards over boards so it can be ~15mm thick. Once you find the first screw/nail like you said you did with the smaller magnet, move 300-400mm right or left depending on which way they run and use magnet to find the next.
Ps the magnet won't fully stick to the nail or screw you will just feel a pull.