Hardiplank typically refers to a type of siding material called Hardie Board. Compared to vinyl and aluminum siding, Hardie Board tends to provide increased durability and longer warranties.
Unfortunately, stud finders cannot always find studs behind Hardie board siding. If you need to anchor something on the exterior of your house, you need to secure it to the studs.
Adding weight to the hardiplank is likely to cause cracking or chipping. Use the following tips to locate studs on the exterior of your house.
Find Studs From the Interior of Your Home
Finding studs inside your home is often the easiest alternative to detecting studs from the outside. If you cannot detect studs behind hardiplank, try finding one inside.
Locating a stud near a window makes it easier to find the same pot on the exterior of the property.
Measure the distance from the edge of the glass to the stud. Use the same measurement on the exterior of the house to find the same stud.
Do not measure from the trim of the window, as the trim dimensions may vary on the outside. However, the distance from the edge of the glass is identical on both sides.
If the wall has no windows, measure the distance from the inside corner of the wall to the stud. To transfer the measurement to the exterior, add the total thickness of the adjacent wall.
The standard wall is about 4.5 inches thick without siding. With standard lap siding, the wall should be about 5.25-inches thick.
Most walls include a half inch of drywall. The 2×4-inch studs add 3.5 inches to the thickness.
The boxing adds another half inch while standard lap siding adds three-quarters of an inch. This brings the total to 5.25 inches.
For example, if you find a stud 32 inches from the inside corner inside your house, the same stud should be 37.25 inches (32 inches + 5.25 inches = 37.25 inches) from the outer corner on the outside of the house.
Find the Spot Where Two Butt Joints Meet
If you cannot find studs from the inside, you may locate the studs by finding the area where the two joints meet.
Hardie board siding is typically nailed to a plywood or oriented strand board (OSB). Before installing the siding, the locations of the studs are often marked with marker or chalk lines.
The siding is then fastened to the plywood or OSB by blind nailing or face nailing. Both methods involve nailing the siding to the studs by staggering the butt joints.
If you can find where the butt joints meet, you can find the location of the studs. With face nailing, the strips are fastened using siding nails along the bottom edge. However, Hardie Board is often installed using blind nailing.
With blind nailing, each strip of siding overlaps the nails of the strip below, hiding the nails. You can try carefully prying the bottom edge of a lower strip to find the nails.
Use an Outside Corner to Find the Typical Stud Placement
Builders often use the outside corner of the floorplan as a reference point when installing the framing. For example, a builder may place the first stud 16 or 24 inches from the outside corner.
Unfortunately, not all builders use an outside corner as a reference point. Builders may also start at either end of the wall.
You may also detect the studs from the basement. If your home sits on an unfinished basement foundation or a crawlspace, you can inspect the floor joists. The studs are typically directly over the floor joists.
Remove Hardie Board Siding to Find Wall Studs
If you cannot find a stud using the previous methods, you may need to remove a section of the Hardie board siding to find the wall studs.
You will need a flat pry bar and a mallet or a hammer to remove the siding. Start by sliding the thin edge of the pry bar under the lower edge of the strip of siding that you want to remove.
Use a hammer or a mallet to carefully push the edge of the bar behind the siding. Gently pry the strip of siding toward.
You may only need to remove the siding an inch or two to detect the nail pattern underneath. If you cannot detect the nails, continue to carefully pry the siding.
Place the pry bar under the first nail and smack the other end with a hammer or mallet. Repeat this process until you have removed an entire row of nails.
You should now be able to remove a strip of siding. After removing the siding, you can examine the length of the exposed wall to find the stud.
As mentioned, the studs may be marked with a marker or chalk line. If the studs are not visible and a stud finder cannot find them, you can try drilling into the plywood or OSB sheathing.
How to Screw into Hardiplank
After finding the studs, you need to use caution when drilling into Hardie board siding. Hardiplank is made from fiber cement and may crack or crumble when weight is added.
When drilling into a wall, you typically use a drill bit that is slightly smaller than the screw. When drilling into Hardie board, you should typically use a slightly larger drill bit.
Hardie board can shift, contract, and expand slightly throughout the seasons. Using a larger hole decreases the risk of the screw and fixture placing extra stress on the siding.
Hardie board (hardiplank) siding is one of the most durable types of siding available, but it can also block stud finders. You also need to avoid hanging items directly from the siding, as the extra weight may cause the siding to crack or crumble.
If you cannot find studs under hardiplank, try finding the studs from the inside of the house. Measure from a window or add the thickness of the adjacent wall to your measurement.
You may also find the studs by locating the butt joints or gently prying the edge of the siding up using a pry bar and a mallet or a hammer.