Which Way Do Floor Joists Run?

So your doing a little work in your home and need to work out which way your floor joists run, how do you even do this without taking up all of the floorboards? Well, luckily for you there is a really simple way to figure this out.

Which way do floor joists run?

The joists under your floor will run in the opposite direction of your floorboards.

The above image shows what I mean really well. You can see how the floor joists run the opposite way to the floorboards. So if you want to know which direction your floor joists run just look at your floorboards.

Floorboards have to run across the joists or else they would not be supported so this method works everywhere that you have floorboards.

In most houses, all of the joists will run the same direction but this is not always true. In some properties, they can run different ways in different rooms although this is very uncommon and mainly seen in older or extended properties.

What about chipboard floors?

This is all well and good, but what do you do if you have chipboard floors rather than floorboards. Chipboards floors are found in pretty much all newer homes as builders have moved away from floorboards.

So what do you do now then?

Well, the same method with the floorboards holds true with chipboard floors, it is just a little harder to spot.

Because the chipboards are larger it can be harder to spot which way they are running. As with the floorboards though they must be running perpendicular to the joists. if not then the edges of the boards would not be supported.

In the image above the joists will be running in the same direction as the laminate that is being laid on top is.

Using Screws/Nails

You can also spot the nails or screws in your chipboard floor to- workout where the joists are. The nails or screws will obviously be going into a joist so if you can spot where they are you can therefore work out exactly where the joists are and where they run.

Using a stud finder

You may have some success finding your joists by using a stud finder. These can detect the joists through the floor.

However, your mileage will definitely vary with this. While some people swear by stud finders I have never personally found one that works reliably.

Tiled Floors

With a tiled floor, it will be very difficult to know for sure which way the joists run.

They will probably run the same way as the other rooms on that floor, but if they swap and change, or if the tiled room is in an extension then this may not hold true.

You can often use the ceiling joists as a way to work this out. They will commonly run in the same direction, although again this is not a failsafe and can be incorrect sometimes.