Water Penetration
Most serious wall problems are related to water in one way or another. Rainwater may enter wall systems in several ways. It may be driven by wind, it may enter either by gravity or by capillary action.
Condensation. Water may also be a problem in wall systems if warm, moist air moving through the wall (from indoors in cold weather and from outdoors in warm weather) is cooled and deposits condensation inside the wall system. Smaller amounts of condensation may also form if moisture moves into the walls by vapour diffusion.

Implications. You should watch for water damage to wall systems, although in many cases you won’t be able to see it. If the siding is deteriorating, it is a good indication that there is some damage behind it. However, in many cases the siding looks fine while the sheathing and wall structure behind deteriorates.

Drying potential. The ability of a wall system to dry often determines the amount of damage done to the cladding and the structure. Wall systems with sidings that have good drying potential, such as aluminum or vinyl, may be less likely to suffer damage than synthetic stucco, for example, which has poor drying potential.

Strategy. As you look at exterior surfaces, look first at the cladding materials and see if they’re in good repair. Second, try to determine how water might get into the wall system and whether there are any areas where you might reasonably suspect concealed damage. Your inspection of the inside of the building should focus on the vulnerable areas that you noticed outside. In some cases the water getting into the wall system will show up on interior finishes, allowing you to confirm your suspicions. However, damage to wall assemblies doesn’t always show up on the building interior — at least not in the early stages.
Pay attention to the drying potential of the wall system. Brick veneer systems with vented rain screens have good drying potential, whereas most stucco systems do not.

Too Close to Grade
Wall cladding materials should be six to eight inches above grade to protect the cladding system and the structure from water damage. This means that we can see some of the foundations above grade and below the siding. Foundations are designed to withstand the moisture in the soil. People may not like the appearance of exposed foundations, but from a functional standpoint, we want to see them.
Masonry. Masonry should usually be at least six inches above grade. There are exceptions because some bricks, for example, are designed for use at and below grade. You’ll be able to tell on older buildings whether the brick was designed for use below grade, by looking for damage. On new homes, it’s hard to know. You should describe any new brick within six inches of grade as suspect, but allow for the possibility that it’s going to be all right.

Other sidings. Most other sidings, including wood and wood-based products, stucco, fibre-cement, metal and vinyl should be at least eight inches above grade.

Causes. Siding materials too close to grade are typically the result of:
• Poor construction and landscaping.
• Grade levels altered during landscaping or surface water control work.
It’s possible that the siding is too close to grade because the building is settling. But there are bigger problems if this is the case.

Implications. It’s easy to recognize the damage to the wall cladding materials. This may include:
• Spalling and cracked brick and missing mortar.
• Obstructed weep holes in masonry veneer.
• Rotted wood.
• Swollen, buckled or cracking wood-based products.
• Peeling paint.
• Staining.
• Rusted fasteners.
• Rusted lath and drip screed on stucco.

Weep holes covered. In some cases, veneer walls with weep holes and flashings along the bottom course suffer dramatically if the weep holes are below grade. Water won’t be able to drain out, air won’t be able to get in, and moisture may seep from the soil through weep holes. Severe spalling can occur.
The more serious and concealed implications are the damage to the wall and floor structures behind the siding. This includes rot and insect damage at sheathing, studs, sill plates, headers and floor joists, for example.
Damage to interior finishes and components is also possible. Sometimes it’s not visible until considerable damage has been done. This may be the first indication that there is a problem.

Strategy. Check around the building perimeter for adequate clearance between siding and grade. Can you see part of the foundation? Where the siding is below or too close to grade, look first for damaged siding. If possible, probe to look for damage to the structural members behind.
Note the areas where siding is too close to grade and check inside the building for evidence of water leakage and damage. Try to find the top of the foundation wall. How far above grade is the top of the wall?

The worst case. The foundation wall may be too short to allow the siding to end six to eight inches above grade. This is the more serious situation. We can’t remove soil and create a trench around the house because we’ll have a chronic flooding problem as surface water is funneled against the house. The foundation is ideally raised to solve the problem, but this can be disruptive and expensive.

A better case. If the siding is too close to grade because the grade has been elevated to form a garden, for example, the solution may be to restore grade level to its original position. This is less disruptive and expensive.

Another better case. If the siding has simply been installed too low, the solution may be to remove the bottom few inches of siding. This is only practical if the foundation is tall enough.

Masonry veneer walls. Masonry veneer walls typically have weep holes and flashing near the bottom of the wall. Look to see if these have been buried. There should be a weep hole (missing vertical mortar joint) about every fourth brick along or near the bottom of the wall. Buried weep holes can lead to considerable damage to the brick veneer and the structure.

Too close to roofs
Siding materials should not be chronically wet. We’ve talked about this with respect to grade level. It’s also true where the bottom of the siding intersects a roof. On dormers, for instance, the best practice is to keep the siding material two inches above the roof. There are step flashings under the siding and roof, so it’s okay to keep the siding above the roof surface.

Causes. Wood and wood-based products are particularly vulnerable to moisture wicking up into and damaging the siding. End grains of wood and cut edges of hardboard, OSB and plywood draw moisture into the wood enthusiastically. It’s common to see siding deterioration along a roof/wall intersection.

Implications Again, water damage to the siding and possibly to the structure behind are the implications.
Most sidings discolour if they are chronically wet. Paint may peel. Stucco may soften and crumble. Brick may crack and spall, especially if the moisture in the brick freezes. Efflorescence may develop on the brick.

Strategy. Look for a one to two inch separation of siding and roofing materials. Where there is little or no clearance, look and probe for deteriorated siding materials.

Planters or gardens
Gardens should not be built against houses if they push earth against the siding. For instance, if there is a raised planter with three sides against a house, the home’s wall acts as the fourth side. Siding materials are not designed to be in contact with earth. What’s worse is that people water their gardens so the soil is perpetually damp.

Causes Planters and gardens against siding are a landscaping problem.
Implications. The implications are damage to the siding and wall structure behind and below.

Strategy. Look for siding to be six to eight inches above exterior grade. If the siding itself is susceptible to water damage, it should be eight inches above grade.
Where you see raised gardens or planters, look for evidence of damage to the siding on the outside and look for evidence of water penetration and damage on the interior.
Raised planters close to buildings should have four sides and should be set out roughly two inches from the siding. This is not a common detail but it is easier on the building.

Insulation problems
Sometimes you will see a large number of patched holes on exterior wall surfaces. If these are in a uniform pattern, they often indicate insulation blown into the wall. This insulation can include cellulose and controversial materials such as urea formaldehyde foam.

Causes. Adding insulation through building exteriors is a retrofit to reduce energy costs and improve house comfort. This approach is usually taken when no interior renovations are planned but insulation improvements are considered a priority.

Implications. Adding insulation from the outside creates a number of holes in the exterior siding that may or may not be properly patched. In some cases, the patches are visible. In other cases, they are patched so well they are invisible.

Possible leak spots. Poor patches may be water entry points.

Insulation may cause damage. Insulation in old walls can reduce temperatures in wall assemblies and result in condensation problems where none had existed before. The insulation makes the wall cavity colder. Since insulation is often added without providing an air/vapour barrier, there’s a higher risk of the warm, moist air, which leaks through the walls, condensing within the wall system.
Strategy. Watch for patched holes that suggest insulation has been blown in. It’s often not done to the whole building because it’s expensive. Watch for areas on the north or west sides of buildings, which are typically colder. Watch also for small areas that project out from the house. They tend to be cool and uncomfortable. This includes second floors overhanging first floors, bay and oriel windows, etc.
Check that the application holes have been patched and are weathertight. Suspect concealed water damage to the walls caused by condensation, especially in cold climates. Watch for evidence of water damage, especially near the bottoms of wall assemblies. Again, you’ll have to check on the inside and outside of the building.

Summary. Water kills houses. It’s a problem at roofs, at foundations, and on the exterior cladding. If you think about nothing else as you inspect the outside of homes, think about water getting into the building. CC

Carson Dunlop and Seneca College have partnered to offer a 10-subject certificate program in home inspection, available in an evening classroom format, as correspondence or online. The information for this issue of “Contractor University” was reproduced from the “Exterior Subject” of the Seneca Home Inspection Training Program. For information on courses call (416) 491-5050 ext. 2515 or visit http://www.senecac.on.ca/parttime/homeinspection/index.html.
To learn more about the textbook and other publications that are available, contact (416) 964-9415 ext. 251 or visit www.carsondunlop.com”