If you’re shopping for a new home or getting ready for seasonal maintenance, it pays to know about the different types of siding, and what red flags indicate a serious issue.

In the best possible scenario, you’ll inspect a home’s siding with a set of the manufacturer’s installation specs and a copy of the local building code in hand. Top-tier professional home inspectors will arrive at a home with this information either in their head or easily accessible.

The good news is that even if you’re not a home inspector, there are a number of clues you can look for that will tell you whether or not a home’s siding is in good shape. 

Tools Required

You don’t really need anything other than your eyes and patience to inspect siding, but some supplemental tools can make things go much smoother. Since sections of siding are often too high for easy examination, a pair of binoculars can be very useful. A ladder can give access to hard-to-see areas, and a tape measure and screwdriver are always helpful to have along.

“You’ll need binoculars, a ladder, and a tape measure.”

During your siding inspection, the two key things to look for (no matter what kind of siding you have) are proper installation and post-installation damage.

Proper Installation

The exact definition of what constitutes “proper” installation will vary by material, manufacturer, and site-specific requirements. However, the basics of professional installation are universal, and apply across the board.

The Fit

When you look down a large run on a wall, the siding should not have waves or ripples in it. This is often a symptom of installers fastening siding too tightly to an uneven wall. Siding should be firmly connected but be able to breathe. Think of siding like a home’s clothes: you want your clothes to be a good fit, not too loose, and not so tight that heat and moisture gets trapped in with you.

Windows and Doors

Pay close attention to corners and openings such as windows and doors. The point of siding is to shed water away from the home and around any possible paths to the inside of the home. Any signs of house wrap or sheathing peeking out from behind the siding is a problem, as is any sign of polling or standing water.

Look for the fail-safe in the siding’s installation. No siding will keep out 100 percent of moisture 100 percent of the time. Therefore, it’s vital that it be installed with the assumption that moisture will get behind it at some point.

Siding is just a single layer of your home’s protection, and the next layers should stop moisture that gets behind the siding. There should always be an escape route that allows water to drain off or easily evaporate. This is why the bottom line of siding is never caulked closed–any moisture that gets past the siding should be able to drain down the side of the sheathing and come out at the bottom.

Proper Fasteners

Contractors should be using the proper fasteners (usually a specific type of nail) during installation. The exact type of fastener will depend on the product, but if you see rust streaks, that’s a strong indication that the wrong type of nails were used. These trails will show up even on siding materials that won’t rust on their own.

Caulking

Lastly, look for areas that have degraded caulk or are missing caulking altogether. If you see caulking that has shrunk or separated, then it should be scraped out and replaced with an appropriately colored silicone caulk. If you see an area that you think should be caulked, ask a pro first—sometimes those are intentionally left open to serve as weep channel in case of water build up.

Post-Installation Damage

No matter how good of a job the installers did when the siding went up, after years exposed to heat, cold, rain, hail, and errant baseballs, siding will eventually begin to show its age. While standard wear and tear is inevitable, during your inspection you should search for signs of excessive damage or minor damage that will become a serious issue if not addressed.

Look for areas of dry rot, animal damage, and (if you’re looking at a new home) evidence of recent repairs. Any of these items is not cause to walk away from the home, but rather to slow down and make sure you understand the cause and extent of the damage. Damage that occurs post-installation is often a one-time occurrence, and is purely aesthetic in nature. Look it over to see if it’s created any further problems, and if not, you should be able to get a fairly straightforward repair estimate from a siding installer or handyman.

Once you look at the whole picture, you can then focus in on specifics for your specific type of siding. While there are a number of types of siding that you may find it on a residential building, we’re going to look at a few specific red flags for the most common types of residential siding.

Wood Siding

With classical appeal and a long history, wood siding can look great and last the lifetime of a house. The most common maintenance issue with wood siding is paint, as it requires regular upkeep. Watch for signs of worn or peeling paint. Any such areas that have been allowed to sit are susceptible to additional damage from the elements.

Peeling paint may be a sign of improper application and should cause you to examine the rest of the siding with a more critical eye. However, if the paint job is more than 7 to 10 years old, then it’s likely simply worn off over time, and doesn’t necessarily indicate a larger problem. Keep in mind that peeling paint will need significantly more prep time when it’s repainted, as any loose material will need to be scrapped off.

Pay extra attention to the lowest run of wood siding. It’s not unusual for homeowners to make adjustments to the landscaping along the home, and they sometimes raise the grading (soil level) high enough to come in contact with the bottom of the siding. This is a recipe for disaster, as it creates a high-moisture situation that can cause the siding to lose its structural integrity, as well as providing wood-eating insects an express lane onto now-damp siding.

From the ground, look at the profile of the roofline. See if you can identify any areas where water will build up–such as the junction of two roof slopes—or where water will splash back up onto siding, which is often less able to deal with water coming at it from below.

Use your hands while inspecting wood siding. If the wood is soft or spongy, then it’s a clue that there is some loss of integrity. If your finger actually pushes into the wood, then there’s a serious problem that needs to be remedied. 

Vinyl siding

Vinyl siding is extremely popular, and can be found in all regions and climates since the 1970s. Vinyl will expand and contract over time, so proper installation calls for nails to hold the material securely in place, but not overly tight. Be on the lookout for buckling along the length of the panels, which is indicative of too-tight nails. As a general rule, the siding should be installed with enough play between the siding and the home—about the thickness of a dime. This same expansion/contraction cycle means that siding panels should have 1/4” clearance around openings and stops, and it should end in a J-channel termination strip, for both aesthetic and water shedding reasons.

And although vinyl siding is more flexible than aluminum, it can still be damaged after installation. A sufficiently strong impact (especially in the winter, when the siding is more fragile) won’t leave a dent, but can cause a crack. If that happens, that piece of siding will need to be replaced.

Aluminum Siding

Beginning in the 1940s aluminum was a wildly popular choice of siding material, until vinyl began to surpass it in the 1970s. It’s a perfectly good siding material, but the lower cost and resilience of other options has caused aluminum to fade in popularity.

Aluminum siding is often painted as its original color fades or falls out of fashion, and it can look great with a fresh coat of new paint. Unfortunately, scratches will quickly reveal the metal underlayer, which means even small damage to aluminum siding is highly visible. The scratches won’t rust (another useful quality of aluminum) but they can corrode, so should be addressed by replacing or repainting the panel.

The thin metal surface of aluminum siding dents easily. It’s common to see dents that are baseball-sized, or to see two dents a couple feet apart near a window—the remnants of a handyman who didn’t take sufficient care with his ladder. Some higher-end aluminum siding has rigid foam on its back side, which reduces this risk and also increases the insulation value of the siding.

Fiber Cement Siding

Fiber cement siding looks great, with tremendous resilience and a long functional life. It also has a number of specific requirements that must be met in order for it to meet its full potential. The most noticeable of these is the gap required between the siding and any flat surfaces. The exact measurement varies by manufacturer, but all versions of fiber cement siding need to have this spacing in order to avoid exposure to standing water. A top-tier contractor will install a ‘kick’ flashing that makes the gap less visible, but it needs to be there to keep the warranty in effect.

As you’d guess from its name, fiber cement siding can take quite a beating. While it’s far more resistant to impact damage than other types of siding, it will snap or shatter if struck hard enough. An errant pop-fly from the local little leaguers? No problem. But a major-league fastball traveling at 100 mph is going to do some damage.

Asbestos Siding

The word “asbestos” causes most people to get nervous, and for good reason. It has been linked to numerous health risks, and the use of asbestos in building materials has been banned since 1973. However, asbestos is only dangerous when inhaled or consumed. If siding shingles are intact, they are not a health risk.

This means that a well-maintained asbestos sided home is perfectly safe, but proper maintenance must be kept up.  Repairing damaged or deteriorating asbestos siding is much more involved than repairing other siding material in the same conditions. It can be difficult to locate replacement pieces of asbestos siding, and safety concerns mean that it can’t be repaired in the same way as wood siding.

 

Remember that you shouldn’t panic when you see something that looks incorrect. Manufacturer’s specs, local codes and site-specific features may mean that something that seems questionable may make perfect sense. Warning signs are just what the name implies: signposts that direct you to the real problem. That problem may be trivial or may be serious, but either way it would have gone unnoticed if not for your inspection. Good luck!

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