How To Examine The Exterior Walls Of A House For Defects

The inspection of exterior should commence as soon as you make the first initial walk-about around a house.

A mistake a lot of homeowners and buyers make is to meticulously look for defects on walls without taking a big overall view of it.

For example, looking for damaged areas without observing the wall as a whole. What’s the point in finding no noticeable scratches but not seeing that a wall is warped out of shape?

Inspecting exterior walls

Foundation walls beneath the house extend upwards into exterior walls.

Most structures of residential homes will have exterior walls made in one of the 3 most popular materials.

  1. Wood frame
  2. Masonry
  3. Combination of wood and masonry (veneer wall)

Wood is used most of the time because of it’s ease of availability. Builders are also very well adapted to the traditional techniques of constructing like balloon framing and platform framing.

Building with 2×4 or 2×6 studs also enable space within the walls to install wiring for power, pipes for plumbing, and insulation.

Exterior walls serve the primary function of supporting floors, vertical load, roof, and basically anything you can think of. On top of these implied responsibilities, the outer covering (siding) also have to function as a shield to provide protection against elements outside.

While it is not possible to dismantle a wall to see what’s found inside during an inspection, they are usually made up of materials layered over one another. In no particular order, you would find a plasterboard, insulation, sheathing, sheathing paper, siding, held up by studs and a sill plate.

Unless you see particular spots of rot, deep stains, damp wood, or signs of termites, you wouldn’t need to probe the wall with a tool to test the condition of it.

Anyway, it’s not recommended that you punch holes in your wall without knowing exactly what you are doing.

For the most part, your inspection of the exterior wall will be focused on the siding as this is the surface that is easily observable for defects.

A good exterior finish should be able to serve it’s primary function of protecting the house from the weather. It should also have the ability to “breathe” allowing moisture to pass through.

Ideally, it would also be low maintenance and blends nicely with the overall style of a house.

Exterior siding

There are various types of exterior siding in the market. And every so often, a new technology enter the market hitting the mainstream.

New homeowners often neglect the importance of the exterior wall as their focal point is often on the interior design. And they can often get away with it not causing major problems to the house as a family’s first home is often just a place to tide over until the household have enough financial power to purchase their dream house – The one they really want.

This is also partly due to inexperienced homeowners assuming that the exterior wall and siding is impregnable by default.

However experienced homeowners will know that good quality sidings are critical to a house’s longevity. And a sturdy dependable siding will need little major maintenance except the customary touch up of paint, sealing of cracks, replacing rotting or loose sections, etc.

And they usually learn about his from the school of hard knocks.

Sometimes, siding can be utterly and completely neglected by homeowners that the only viable option is to overhaul the entire siding.

When examining sidings, pay special attention to walls that face South-Southwest as they receive a daily barrage of attack from the sun. This deteriorates them at a faster rate and thus, more vulnerable to defects.

Also note that the lowest most point of the siding should not be less than 8 inches above the ground. This is to avoid moisture from the ground. It is also a basic deterrence against termites.

Should vines grow against a wall, it is suggested that they be removed. This is because they can not only cause damages, but also conceal defects from the untrained eye.

Siding material

In order to conduct a proper assessment of exterior siding, you need to know the material that is used to fabricate it. This would allow you to watch out for specific problems known to specific material.

The following are some of the more commonly used materials.


Wood by itself is a very broad definition. Because there are various types of wood commonly used for exterior wall siding.

  • Shingle/shakes
  • Boards
  • Plywood
  • Hardboard

When scrutinizing wood siding, areas that are most prone to defects are corner joints, and joints attaching the siding to window and door trims.

On combination siding where wood and masonry are both used, the space where they join can often contain small gaps that are not sealed properly. Allowing water to penetrate.

Wood is also susceptible to fungi and mildew growth. As unsightly as these dark spots can appear, they do not directly cause the siding the decay and can usually be removed with chemical swipes.

However, don’t confuse these blotchy spots with stains caused by rust. Theses brown/black stains can be caused by metal used in the fabrication of the wall. It is a huge challenge to remove these stains and would most probably require a replacement of the affected planks.

Other than that, decay and rot has always been associated with wood.

Shingles and shakes

These are usually made from redwood or cedar. While this materials are very resistant to decay, they ultimately discolor over time.

This means that you can almost never find a replacement shingle that matches the color found on the existing wall.

In this case, homeowners and sellers especially like to install a new coat of paint for aesthetic purposes.

Shingles can be fragile and it’s no surprise to find defects on them like cracks, chips, and falling off.

Open joints around window and door frames can be prone to water seepage.

And remember the South-Southwest section of the wall that gets more exposure to the sun? A consequence of this is that shingles in this area are prone to warping.

If you are meticulous enough to inspect individual shingles, take a look at the thickness of them. Low quality shingles can be thin on top and thicker towards the bottom. These are specifically manufactured for budget installations.

They have a shorter lifespan and the thin portion can break easily. So you won’t be wrong to predict that a lot of maintenance and servicing fees are coming your way in future.

Shingles are also supposed to be fixed firmly. They are not like hair on our head that flaps when the wind blows. So if you find shingles that can be lifted, it’s an indication of poor workmanship.


Wood board siding is used by builders in both vertical and horizontal orientation.

From a visual perspective, horizontal layouts can make a house appear “fatter” while vertical layouts can create a “taller” appearance.

Something that professionals know but newbies often forget is that when wood boards are used for siding, the planks have to be free of knots.

This is because shrinkage over time can cause the knots to fall off. Leaving you with big holes on the wall.

The surface is finished with weather-resistant paint by default for protection. So assessment has to be done on the paint.

Undesired paint conditions include:

  • Peeling
  • Flaking
  • Bubbling
  • Missing sections
  • etc

A lot of paint defects originate from poor or wrong application technique. If there are moisture related defects, you will have to take precautionary measures after moving in to preserve your new coat of paint.

Whenever you find holes or gaps on wood board, it is essential to patch them up with wood filler. Don’t forget to take a look at exposed end grains when moisture can attack.


Plywood are basically veneer layers of different material glued together to form a panel. The logic is that this fusion of material will create a stronger and more durable variant of wood.

Because of this layering method, a prettier top layer can be used for cosmetic purposes. Some can contain beautiful grains, textures and grooves.

And as you might expect, all good things come to an end. There are disadvantages to plywood as well.

Because plywood is a mixture of various layers of wood, it is prone to water seepage. This is also a reason why it is almost exclusively setup vertically. Buckling and warping can also be a problem.

Look for spots with water stains. Especially in open and loose joints.


Hardboard is manufactured via a bonding process of wood fibers using intense heat and pressure.

And because it is in a way created from scratch, various customization and design options are usually available. But it is not as dependable as plywood.

Hardboard is prone to cracks, chips, and breaks.


Aluminum and steel are getting very popular with newly constructed homes. So popular they are that houses with wood siding often choose aluminum when replacement is inevitable.

Because homeowners still love the natural beauty of wood, aluminum siding are often fabricated to comprise of wood-resembling texture.

It’s not corrosive and although there are certain instances where termites chewed through them, it is accepted as termite-proof as well.

It is basically as close to “set and forget” as you can get.

So why don’t everyone just get them installed?

Because there is no way you can rectify it when dented. This can happen if something knocks into it hard enough. And because it is a metal, there is always a concern with how it conducts electricity.

There is also 2 main schools of thought with installing aluminum as exterior siding.

  1. To install with insulation; or
  2. To install without insulation

There are pros and cons for both methods. But we will not discuss it here.

To check if you are working on one with or without insulation, tap on it. A hollow sound indicates one without insulation. If you still can’t figure it out, gently and firmly press down against it. One with a backer board, and therefore insulation, will be unmistakably firm.


Asphalt siding can be in the form of rolls or shingles. It’s exposed surface is often embossed to mimic the appearance of bricks.

While pleasing to the eye, it can turn brittle with time. Asphalt siding is slowly phasing itself out as better materials with better value emerge in the market.

When inspecting a asphalt siding that has aged, defects are often very obvious. You won’t need an eagle eye. There will be a flurry of tears, cracks, flakes, chips, etc.


It’s not easy to find a distinction between aluminum and vinyl from simple observation. They can look totally alike to each other.

The trick in differentiating them is to observe the end cut, or maybe a scratch. Aluminum will undoubtedly have a metallic look when exposed under the paint.

The good part with vinyl when compared with aluminum is that it does not dent. It will flex back into shape when you knock on it.

But a major hitch is it’s brittle nature during winter.

This should instinctively tell you that you should check for cracks, blisters, breaks, and even broken sections hanging on by it’s end.

Asbestos-cement shingles

These are no longer in production because of the health hazards associated with asbestos. Even so, many older homes still have them because of it’s low cost.

This is a material that’s very durable and requires very little maintenance.

They are however, brittle. Meaning you will have to look for typical signs of damage.

And just like wood shingles, you’d have a hard time finding a replacement piece that matches the color of the existing wall… if it’s even possible to find one.

It suffers most of the problems found in wood shingles.


This is a hybrid cement containing various materials that supposedly improves performance.

It is fire-resistant, rot-proof, warp-proof, and delamination-proof. It is also highly resistant to termites, cracking and damage.

With so many advantages, it’s something hard to say no to.

However, it’s more complicated to install.

Look for defects related to installation like exposed nails, alignment issues, damaged sections, etc.


This is basically a surface finish applied to wall in two coats. And if a homeowner is willing to go through with such a hassle, it must be some good stuff.

Stucco is resistant to almost everything we have discussed previously. More than that, it also has almost all the advantages of the other materials too.

It can be painted, finished, and even take on embedding of other materials like stone for visual effect. Synthetic stucco is now slowly making it’s way into the market.

You can normally tell what type of wall is under it by tapping on it. Stucco coated on masonry have a more solid sound compared to wood.

The one weakness it has, which is quite a big one, is it’s prone to cracks. Cracks can appear from house movement caused by wind, wood expansion and contraction, or even extreme hot and cold weather.

This should give you a major clue of what to look out for.


The structure of a masonry wall is very different from a typical wood wall. The structural members can sometimes be made up of bricks, concrete, or even stones. Without going into the details of the differences, the main pitfall of masonry is it’s low insulation.

While enhancements can be made to it to improve it’s thermal performance, the sheer number of available options can give the average homeowner a chronic headache.

It has a rigid nature. Meaning it has the same vulnerability as stucco.

Other than that, it is unique in that is prone to efflorescence. This refer to soluble salts in masonry that is brought to the surface by moisture.

While this salt can be removed with cleaning, constant re-occurrence can leave you cursing the day you decided on masonry exterior wall siding. A recurring problem suggests water is causing chaos deep within the walls.

Since it is prone to cracks, water condensation is a problem that is almost a certainty.

This means that other than the typical cracks and chips to inspect for, pay particular attention to areas and intersections where the wall joins other fixtures like window frames and doors.


Depending on how the bricks are installed for exterior surfaces, it can be classified as both solid masonry or combo.

Bricks add that touch of rustic design to a house that other materials just cannot achieve. Some homeowners absolutely love the look of bricks from the outside.

But they require the keen eyes of an inspector when seeking defects.

Mortar between the bricks have a tendency for gaps to appear. This is partly due to water flowing down along these areas when it rains. Openings tend to appear in areas where the bricks meet with other materials like wood framing and eaves.

Spalling is a common concern when moisture is trapped in brick walls.

Also look for sloping and settling. And take cracks very seriously. Because bricks are layered one over another and held together by mortar, foundation issues can often literally tear the wall apart.

Lastly, vines that climb up a brick wall. They can damage mortar and thus allow water to seep through the cracks.