When you hang pictures, mount shelves or even wall mounts for flat TVs, you need to make sure that all of these are securely fixed in the right place. Unless you want to fill a wall with holes, screw marks and get very frustrated, you need to locate a bearing post before you begin. You can use a suitable electronic or magnetic tool or examine the surface of the wall to understand where this structural element is.
Steps
Method 1 of 3: with a Detector
Step 1. Purchase a tool that will allow you to find the bearing posts in the walls
It is sometimes referred to as a "detector" or "sensor" and you can buy it at hardware stores, construction supply stores, or home improvement stores.
Step 2. Evaluate the type of sensor you have
Some models are magnetic, this means that you feel a pull when you slide it over a hidden pole due to the nails or cables present on the pole itself; other models instead measure the variations in width of the wall by signaling the presence of the load-bearing structure with a sound or a flashing light.
- Magnetic detectors are less effective than other types because they cannot distinguish various metals. A tube positioned far from the pole makes the sensor react just as if it were an electric wire mounted on the pole itself.
- If the walls are plasterboard, use only an instrument that measures the variations in width. The fact is that the plasterboard has a uniform thickness and any alteration is readily detected; the plaster on the other hand does not have this characteristic and could interfere with the sensor.
Step 3. Calibrate the tool if necessary
Some models need to be set up before use; just lean them against a section of wall without supporting poles and turn them on. The calibration process requires a variable time depending on the type of detector; in some cases a few seconds are enough, in others you have to wait up to a minute. Usually, the sensor indicates the end of the setting or informs you that it is necessary to repeat the procedure.
Detectors that need to be calibrated typically have a system to warn you if you place them on a supporting pole or other structure that interferes with the process, such as a piece of metal; in this case, you have to move them and start over
Step 4. Pay attention to the model you have
There are those that detect the edge of the pole, and if so, you have to repeat the search from the opposite direction to find the other one as well. Additional settings may be required before performing the second detection. The models that identify the center of the pole allow you to immediately find the midpoint of the structure.
If you have an edge detector, remember that the bearing poles have a variable width between 4 and 9 cm, in case a timber with a nominal section of 5x10 cm was used; if the builder used different sized lumber, the posts also have different widths. Therefore, consider asking the construction contractor or homeowner for more information to know the dimensions of these structural elements
Step 5. Slide the tool across the wall to the height you want to hang the object from
Look for the indicator that signals the presence of the pole. Repeat the procedure several times at different heights to make sure you have located the very carrier.
Measure and mark references every 40 cm along the horizontal direction of the skirting board to find the other posts; this is the distance at which the various supports are usually mounted. In older houses you can find them 60 cm from each other; use the tool to confirm that they are there
Step 6. Before using the drill check if the poles are made of metal
In many apartments and offices, metal frames are used instead of wooden ones; in these cases you have to use special hardware, as most wood screws cannot penetrate metal.
Method 2 of 3: Without the Detector
Step 1. Check the upholstery
Any decorative element, such as the skirting board or the molding, is fixed to the supporting posts. You can then locate them by looking for small bumps along these bezels that reveal where a nail has been inserted. The nail holes are filled with putty or painted after the molding is mounted, but they still remain visible to a careful eye.
Step 2. Try tapping
Knock gently on the wall to see if there is a bearing pole based on the type of sound; a hollow area emits a rather low "empty" sound, while in the points where there is the supporting structure you should hear a more acute and full noise. Practice in areas where you are sure there is a pole to "train" the ear.
Step 3. Insert a pin where you think the pole is
If so, the pin should stop penetrating as soon as it comes into contact with the wooden structure; if not, you should encounter little resistance and you should succeed and push it all the way into the drywall.
If you don't find the pole on the first try with the pin, go to the "cable test". Take a metal hanger or other iron wire and shape it into a long, thin stick with a right angle fold; insert it into the hole you just drilled and spin it until it touches a pole. This way you don't have to knock on the wall several times
Step 4. Observe the location of electrical outlets and switches
Most electrical boxes are mounted on the edge of a pole. Turn off the power to a specific electrical outlet and remove the blanking plate. You should be able to figure out which side the pole is on by looking at the position of the fixing screws; if you can't, tap the wall or use a pin to determine the location of the structure.
To find the center of the pole measure a segment of at least 2 cm from the electrical unit. Use the pin technique or tap on the wall to find the width of the load-bearing element; remember that these structures are typically 40cm apart on either side of the socket / switch
Step 5. Calculate the position by measuring the wall from corner to corner
Since the posts are mounted at about 40cm intervals, you can measure the length of the wall to figure out where they are.
Remember that not all walls are divisible by exactly 40, so some frame structures may be closer together than others
Method 3 of 3: in a plaster wall
Step 1. Use the wooden stick to support light objects
Hanging elements from plaster is easier than plasterboard, because this material is applied to an internal structure composed of wooden slats which are generally strong enough to withstand weights of less than 5-7 kg; however, for larger items (like the TV) you need to find at least one supporting pole.
Step 2. Try with a strong magnet or magnetic detector
An electronic sensor that measures depth variations is not suitable for this type of material; the magnetic one (or a very powerful magnet) can instead indicate the presence of the pole to which the slats have been nailed.
- Alternatively, you can use a metal detector to find the area where the slats have been attached to the supporting structure.
- If you have decided to use any of these methods, remember to locate more than one pole and measure the distance between them to make sure you have not located a pole or cable that is not connected to the supporting structure.
Step 3. Do not use the pin test
It is possible to find the posts in the plasterboard by inserting this object into the wall, however the plaster is too hard for the pin, which in any case is not able to penetrate the layer of wooden slats.
- You can still try knocking on the wall to locate the pole. Where it is not there, you can hear a dull and "empty" sound, while where it is present, you can hear a louder and fuller noise.
- Use power outlets and switches as references. Any electrical element is fixed to the supporting poles; turn off the power supply to the specific electrical box and remove the protective plate to understand which side the pole is on by observing the position of the mounting screws.
Step 4. Consider using an anchor
If you use sturdy fastening systems, you don't have to worry about the position of the support structures; some models are strong enough to support several hundred pounds on both drywall and plaster. Remember to always read the instructions very carefully before hanging anything on the wall to avoid damaging it.
