How To Find Floor Joists Under Subfloor

If you miss a joist the screw will spin before the head is driven completely flush with the plywood.

How to find floor joists under subfloor.

These chalk lines run the entire depth of the momplex perpendicular across each floor joist every four feet. The subfloor probably plywood will be nailed to the joists below. The nails tell you where the first joist is and which. Shine a flashlight at an oblique angle over the subfloor and look for the shine off the nail heads.

Put one in every inch in a straight line until you hit a joist. You d be surprised at how fast that can add up to inches. After all joists are essentially just large studs in the floor. A number of test hole locations are within the photo but they are not visible.

The nails that hold the subflooring in place will all have been driven into the floor joists. For example if you need to repair a squeaky floor you will need to be able to find the locations of joists in order to correct the problem. Get some wood filling paste to fill in the holes. If this is the first floor of a house then you can see the subfloor from underneath in the basement.

Look closely at the carpet near the yellow tape measure. Pull back the corner of the carpet padding with the pliers. When you are going 44 feet wide if you get off 1 8 here 1 4 there a hair over there. Might be time to start dropping 2 long screws into the floor to feel where the joists are.

Use standard drywall type screws about 1 to 1 1 2 long to re attach to the joists. Kneel down on the hardwood floor and gently tap the head of the hammer on it paying special attention to the sound it makes. The joists in this part of the house run at a right angle to the yellow measure tape which is consistent with the direction they run in the closet on the other side of the house. It s possible the underlayment is squeaking against the subfloor.

Put on an underlayment refloor with vinyl if that is what you want. This indicates that you have located a floor joist. You ll have to drill small holes to find your first joist but you should be able to measure out 16 inches and go from there. You can guesstimate where the joist is shoot a screw on either side go underneath and measure where the joist is between the screws go back up and use the measurement to hit it.

Its a screw to tighten the sub floor to the joist traditionally connected with a nail which is may be causing the squeek. Move the hammer to the left or the right until the sound changes from hollow to solid.