Proper installation of siding is the key to creating a long-lasting exterior. The process may seem relatively straightforward, but even small mistakes during installation can cause larger problems down the road. From water damage to warped panels and more, improper installation will undoubtedly shorten the lifespan of a siding installation and be detrimental to a home’s curb appeal.
The good news? These issues can be avoided by taking the right steps from the start.
By understanding the most common installation pitfalls and how to avoid them, contractors and homeowners can achieve a siding installation that not only looks great on day one, but continues to perform throughout its lifespan.
Avoid these top five mistakes.
#1 - Poor Preparation
Rushing through installation without properly preparing the surface can lead to siding failure, uneven appearance, and water infiltration. Skipping crucial steps such as inspecting the sheathing, leveling walls, or cleaning the surface compromises the siding’s performance.
- Inspect the wall surface thoroughly – Look for cracks, bulges, signs of mold, or water stains. Any underlying issue will worsen once the siding is installed over it and air movement is limited. Remove and replace rotted or weakened sheathing and address the source of moisture before proceeding.
- Establish a level reference line – Use a level and chalk to mark a straight baseline for the starter strip. This ensures every subsequent row of siding runs evenly.
- Mark wall studs – Use a pencil or chalk to clearly mark stud locations so you can secure nails or fasteners into solid framing in conjunction with sheathing.
- Follow manufacturer guidelines exactly – Each siding product has unique installation requirements for spacing, fastening, and prep. Adhering to these ensures the warranty remains valid and the siding performs as intended.
#2 – Improper Fastening
Using the wrong fasteners and/or fastening techniques or neglecting proper flashing can lead to premature siding failure, costly repairs, and potential water damage to the structure.
Depending on the type of siding, it is important to adhere to manufacturers’ recommendations for proper fastening and sealing to allow for the necessary expansion and contraction or swelling. For instance, engineered wood and fiber cement are fastened tight, hard nailed to the wall. However, these materials may absorb moisture, creating the opportunity for warping, rotting, or cracks to develop. Alternatively, polymer-based siding or composites should generally be fastened loose to the wall to allow for the natural expansion and contraction that comes with temperature swings.
For polymer-based siding products containing vinyl, rigid and cellular PVC, or polypropylene (including composites), nails driven too tightly can restrict the natural expansion and contraction of the siding, causing buckling or warping over time. Use corrosion-resistant fasteners recommended by the siding manufacturer, and drive them straight and level into the sub-wall and/or framing studs to allow for natural movement. Follow the manufacturer’s specified nail spacing and placement, paying close attention to where fasteners should be positioned on the siding panel.
#3 – Inadequate Weatherproofing and Moisture Protection
Failing to properly protect the building envelope from moisture leads to costly repairs. Without a proper waterproofing barrier in place, water can infiltrate behind the siding, leading to mold, rot, warping, and structural damage. When installing housewrap, missteps like improper flashing or leaving gaps at seams can also lead to damage. Over time, these vulnerabilities can compromise the building envelope, reduce energy efficiency, and shorten the lifespan of the exterior and its framing materials. Moisture damage is often hidden until it becomes severe, making prevention critical from the start.
Here's how to make sure you keep the home protected:
- Always install a high-quality, water-resistant housewrap over the sheathing before siding installation.
- Apply flashing at all penetration points: windows, doors, rooflines, and transitions to divert water away from the structure.
- Overlap flashing and housewrap in a shingle-like fashion so water flows down and out, not behind.
- Inspect and test the weather barrier before installing siding to ensure full coverage and no tears or gaps.
#4 – Poorly Installed Flashing Around Windows and Doors
When it comes to keeping water out, windows and doors are an exterior’s most vulnerable spots. If flashing is not installed correctly, driving rain or condensation can infiltrate behind the siding and quietly wreak havoc inside the walls.
Rot, mold, and structural damage often start small but can escalate quickly, especially in homes exposed to heavy rain or strong winds.
The usual culprits?
Flashing that is cut too short, not overlapped properly, or not integrated with the housewrap. The fix is simple, but critical. Install flashing the right way from the start, creating a continuous, watertight barrier around every opening.
Here are a few quick tips:
- Flashing only works if every piece overlaps and is locked together. Start by installing it from the bottom up, so water naturally sheds away from the building.
- Make sure the flashing tucks under the house wrap above a window or door opening, and over the housewrap below it. This creates a continuous shield.
- Use durable, corrosion-resistant materials, and add sill pan flashing to catch any water that sneaks past the window or door frame.
- Before moving on to the next step in wall construction, inspect each opening carefully. This is an installer’s last chance to catch gaps, misaligned pieces, or missed seams before the siding goes up.
#5 – Failing to Account for Expansion and Contraction
All siding materials are subject to some degree of movement. Engineered wood, real wood, fiber cement, and composites with organic materials tend to be more susceptible to swelling due to moisture, while polymer-based, including inorganic composites sidings, naturally expand and contract due to temperature swings. If this movement isn’t planned during installation, the siding can warp or shift unexpectedly and develop gaps over time. In extreme cases (and depending on material type), panels can even crack under pressure.
These problems often stem from neglecting the manufacturer’s spacing recommendations, or failing to allow clearance around all trims and protrusions. While these issues may not be visible right away, seasonal changes will eventually reveal the mistakes, leading to costly repairs and a shortened lifespan for the siding system.
It is also important to consider the temperature at time of installation. If material is installed on very hot or cold days, the panels may need adjusted spacing to prevent warping or gapping in the future. Understanding the maximum potential movement per length of the product will help determine required gapping based on climate conditions and temperature swings.
Durability for Decades
Avoiding these common siding installation mistakes helps builders, contractors, and homeowners protect their structures for the long haul. One way many of them are doing this is by choosing next-generation composite siding products, such as Everlast® advanced composite siding. It is designed with both durability and installer-friendly features in mind to streamline installation while reducing or even eliminating the risk of warping, rot, insect damage, and moisture absorption.
Each Everlast siding panel is designed to seat securely on top of the next when installed. It is a floating siding system, allowing for expansion and contraction at all termination points with space hidden neatly within the trim. Combined with proper flashing and housewrap, this ensures lasting weather protection.
The result? A long-lasting, maintenance-free exterior that stands up to harsh weather and keeps exteriors looking their best year after year.
Want to learn more about Everlast siding installation? Join our contractor program to receive all the training and support you need to become a leading Everlast siding installer in your area.
