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A house with Mainstreet siding in Colonial White white and black trim.

Installing Horizontal Siding

Preparing Wall Surfaces

The key to successful vinyl siding application is proper preparation of the nailing surface. It is essential that you work over a smooth nailing surface. The more level and even the wall surface, the better the finished installation will look.

The steps involved in preparation differ for new homes and old.

Find here how to install vertical siding


It’s important to work with care and planning as you install siding panels. This is especially true when you’re installing the first course of siding.

For best results, follow these guidelines:   
The key to creating a visually attractive installation is to lap away from areas where people normally walk or gather. For example, on the front wall, work from the corners to the entrance door (so overlaps face away from door).  
On side walls, work from the rear corners toward the front. This approach minimizes the effect of lapping and produces the best appearance. Keep lap appearance in mind throughout installation.

NOTE: Lap appearance is also improved when you avoid using panels less than 3' long.

Slide the first panel into the cornerpost recess. Leave room for expansion. Hook the bottom lock of the panel into the interlock bead of the starter strip by applying upward pressure.  
Before nailing, double check to make certain you’ve locked the panel along its entire length. A slight upward pressure may be required to snap the interlock securely. Don’t force the lock too tightly, however. You may distort your laps. Nail properly. Also, make certain the panel can slide freely. Start at the center of the panel and work out.  
Install the remaining starter course panels, overlapping panel ends. The last nail should be at least 2" to 4" from the end of the panel to allow for a neat lap.  
Remember to leave room for expansion when fitting panels into remaining inside and outside cornerposts.

To transition from brick, stone, or stucco to vinyl siding:

  • Caulk where the sheathing meets the brick, stone, or stucco. Caulk the flashing, and make sure a drip cap is in place.
  • Use J-Channel or starter strip to receive the siding when installing horizontal siding, If you use starter strip, leave 3/4" clearance so that the siding can engage securely.
  • When installing vertical siding, use J-Channel to receive the siding.

Discover how to estimate your vinyl siding installation


To ensure best appearance, position the laps to avoid unsightly joint patterns. The illustration at left shows a well-planned staggering of panel joints.   
Follow these guidelines: 

  • Separate joints by at least two courses. 
  • Avoid joints above and below windows. 
  • Leave at least 3' separating joints on successive courses. 
  • Use short cutoff lengths for fitting at narrow openings between windows. 
  • Follow the planned pattern when applying the next courses of siding.

For best aesthetics, and to avoid potential panel-to-panel interference: separate the vertical alignment of joints by at least two courses, avoid joints directly above or below windows and leave at least 3" separating joints on successive courses.  
You’ll probably have to cut panels to fit under windows. To make this task easier, plan panel positioning as shown at left so a single panel extends beyond both sides of window opening.   
Follow these steps to measure and cut panels:  
Hold the panel in place and mark the width of the window opening. Add 1/4"–3/8" to both ends to allow for expansion. The resulting marks show the location of vertical cuts. Extend the marks onto the panel using a square.  
Create a template for the horizontal cut using a small piece of scrap siding. Lock this piece into the lower panel and mark 1/4" below the sill height. This provides clearance for undersill trim. Repeat the procedure on the opposite side of the window. (You can’t assume windows will be perfectly level.)  
Transfer the marks from the template to the panel. Connect marks using a straightedge.  
Cut the panel, using tin snips to make vertical cuts and a utility knife to make the horizontal cut.

Read more about measuring vinyl siding


If necessary to maintain the slope angle, install furring under the sill.  
NOTE: You can eliminate this step by using dual undersill trim. This trim has two receiving channels. Use the inner channel if you’ve cut the siding panel near the locking edge or any area of the panel that does not lay flat against the wall. Use the outer channel if the cut has been made near the butt edge.  
Use a snap lock punch to raise tab faces on the outside of the panel. Punch out a tab every 6".  
Push the horizontal edge of the cut into utility trim. Slide vertical edges of cut into J-Channels at window sides. Make certain the installed panel locks into the panel below.


The procedure for cutting panels for installation over windows and doors is similar to that explained earlier.  
If necessary to maintain the slope angle, install furring above the window or door.   
Drop the panel into position, making certain it fits into the undersill trim and J-Channel at the top and J-Channel at the sides. Interlock the panel with the siding panels below.


To simplify installation in areas such as that shown in the illustration, install J-Channel on both sides of opening.  
Bow the panel toward you and slip it into the channel, or slide them down from the opening at the top of the windows.  
If the area is very narrow, leave one J-Channel unnailed except at the lowest point (as shown). Bend this channel out slightly to insert panel. When the panel is in place and nailed, nail the J-Channel immediately above the panel and repeat the procedure. Be sure to leave adequate tolerances for expansion and contraction.


Make a pattern duplicating the gable slope. Use this pattern to guide the cutting of panels to fit gable ends.

To make pattern:  
Lock a short piece of siding into the panel gable starter course as shown in the illustration.  
Hold a second piece of siding against the J-Channel at the slope. Run a pencil along edge of this piece, transferring the slope angle to the first piece of siding. Cut along the line using a power saw or tin snips. Use the resulting pattern to mark siding panels before cutting.

NOTE: Double-check the angle on the pattern at every course. If necessary, cut a new pattern.

To install cut panels: 

Slip the angled end of the panel into J-Channel along the gable edge. Leave space for expansion.  
Interlock with the siding panel below.  
If necessary to securely fasten the last panel at the gable peak, face nail as shown in illustration. This is the only place you will face nail. Use a 1-1/4" to 1-1/2" aluminum nail with painted head.

NOTE: Do not cover louvers in gables.

Discover here the Vinyl Siding Terminology

Fitting under soffits

When you reach the last course of siding, you will probably have to rip cut panels lengthwise to fit under soffits.

NOTE: If necessary to ensure proper panel slope angle, make certain to furr out this area.

To cut and install this last course:  
Install J-Channel and undersill trim or dual undersill trim.

NOTE: When applying one accessory over another, align accessories to line up nail slots, or make new slots to avoid pinning the underlying accessory.

Measure from the soffit to the base of upper lock on the previous course of panels. Subtract 1/4". Mark this dimension on the panel to be cut, taking the measurement from the bottom edge of panel.For a more precise cut, repeat this procedure at several other points along the span to be covered by the panel.  
Using a square or straightedge, draw a pencil line connecting these points. Then score along the line with a utility knife. Bend the panel back and forth until it snaps. Use a snap lock punch to create tabs on the outside face of the panel, 1/4" below the cut edge. Space tabs every 6".  
To install, lock the bottom of the cut panel into the panel below. Push the top edge into J-Channel or undersill trim. Tabs will catch in the trim and hold the panel firmly in place.

NOTE: Since you will not nail this last course, it is important that the tabs fit properly in the trim to provide support while allowing movement for expansion.


To finish the top course of siding, attach cornice receiver to the top of the wall under the eave or soffit. Trim the top panel to within 1/4" of the cornice receiver. Using a nail slot punch, punch nail slots 1/4" from the trimmed edge of the siding panel, 16" apart. Nail off the top course, and snap the cornice molding into the cornice receiver. An alternate method is to use J-Channel and furring strips.