Structure

Residential buildings are seldom subject to catastrophic failure – that is to say, they don’t often just fall over!

The structural integrity of a house is of primary concern. The structural system is made up of footings, foundations, exterior walls, floors and the roof systems. These systems must withstand the required forces imposed upon them, such as dead and live loads, winds, earthquakes and other events depending on the location of the building.

Serious structural defects do occasionally occur over time, sometimes with the help of inept workmanship and deterioration of building materials. Unless you have some specialized equipment and a serious understanding of the issues involved, it’s unlikely that you will be able to carry out successful structural repairs yourself.

We recommend that you get at least three written quotations from qualified contractors whenever structural defects are identified.

Cracks can be result of shrinkage, differential settlement, lateral pressure being exerted on the wall by the soil, or poor quality work. Equally deteriorated mortar joints should be repointed.

All cracks should be sealed as a precautionary measure against water penetration into the structure.

In some older homes with masonry foundations, there may be soft, crumbled and flaking units. These should be repaired.

Dampness in a basement is a normal phenomenon that occurs because cool air cannot hold as much moisture as warm air. It does not always indicate that there is a water problem in the basement. Dampness in a basement or crawlspace can be controlled through moisture barriers and with the aid of dehumidification system, and/or with the addition of ventilation. It is not uncommon for home owners to install and run dehumidifiers for the warmer months. This helps in lowering high moisture levels in a home and reduces dampness.

Water seepage is a general term that refers to water intrusion. Water seepage can be caused by a number of factors. It is important to determine the cause and source of the seepage.

Structure

The building structure is comprised of the parts that help it to keep its shape – framing, roof trusses, rafters and so on, and the parts that prevent gravity from pulling it into the ground – foundations, footings and piers.

In any building, the parts that are at the bottom – foundations, footings and so on, have to be strong enough and sufficiently well supported to carry the weight of everything above. So you can see that where homes are built on unstable ground or we where make the ground unstable by constantly soaking it in water (poor drainage, eavestrough, window wells etc.) will increase the likelihood of structural damage.

Foundations
The foundation walls not only carry the weight of the building, but they also stop the soil outside the basement falling in. When the drainage is poor or where the perimeter drain at the footing is clogged or missing, water can build up against the exterior foundation wall. The resulting pressure can cause cracking or often, in the case of masonry block walls, lateral displacement.

Foundation walls also crack as the result of settlement. The ground below the footing sinks and the wall tries to follow but being stiff, cracks in the attempt. Settlement cracks are often easy to repair, sometimes needing only minimal patching or sealing. In some cases, attention to grading and exterior drainage, will prevent or minimize leakage, even if the crack is left unsealed.

Other settlement cracks may present significant structural defects that will need a professional to repair. In these cases the structural problems must be addressed as soon as possible by a qualified contractor or structural engineer, to prevent or minimize further damage or water penetration to the lower levels.

Homeowners and buyers occasionally mistake cracks in the cement parging, for cracks in the foundation wall itself. Parging is the thin cement coating used as a decorative finish to cover foundation concrete or masonry blocks.

The inspection.

Inspectors are often unable to see more than about five or ten percent of the exterior foundation walls because most of it is under the ground! Interior finishes and storage can create a similar problem indoors.

Not all structural problems involve movement and where building components are hidden underground or behind interior finishes or furniture – it may be impossible to determine or identify problems.

The repair of some minor structural problems may be undertaken by the homeowner. (Some minor cracks for instance). Most however need a significant understanding of the problem and the issues involved. Many will need specialized equipment. In the worst cases, your inspector may recommend the services of a qualified contractor or structural engineer.

Basements

Most basements will leak at some time during the life of the building, either from cracks in the walls, the failure of a sump pump or perimeter drainage tile or as a result of poor or inadequate exterior drainage.

Often basements will only leak under certain specific circumstances or at certain times of the year. In these cases, unless there is some evidence of previous water infiltration, leaks can be impossible to detect.

Many basement water infiltration problems can be attributed at least in part, to poor exterior drainage. This includes gutters or eavestroughs, grading, window wells and so on. In many cases – attention to these issues can significantly reduce the problem. Evidence may include visible efflorescence on outer walls, water stains on wood at floor level, and paint peeling on both sides of a concrete floor crack.

Basement walkouts

Many basement walkouts are poorly constructed and often have inadequate drainage. In cold areas, footings are often too shallow to be protected from frost, especially where the walkout was not part of the original construction.

Unless properly designed and constructed, basement walkouts can be a source of leakage and structural problems that may be costly to remedy.

Properly installed however, they are a source of light, access and air to below grade areas, often opening up rooms that would otherwise be used only for storage.

Framing and trusses

Wood or steel framing in exterior walls is almost always structural. Warping, twisting or bowing can be signs of structural problems, which must be assessed on an individual basis.

Interior stud walls may only be room divisions, however some are supporting walls for floor joists, rafters or trusses. Always consult with your qualified contractor before demolishing any walls.

Generally speaking, the steel posts seen in many basements, usually under wood or steel beams, are not moveable, except at great trouble and expense. When finishing basements, try to disguise them into partition walls or create decorative columns around them. Support columns should not be removed without professional advice from a structural engineer.

Roof trusses and truss joists

These are designed by computer and built in factories under controlled conditions. Each unit is specific to the structural requirements of span, load, snow loads and so on. Removing one or more sections (in attics to create rooms or a storage area for instance) will adversely affect the structural strength of the entire unit.

Modifications are generally not acceptable – especially on site. Any alterations or repairs must be referred back to the truss manufacturer for approval.

Engineered wood products such as Truss joists – also known as “Silent Flooring” or engineered joists, are similarly made in controlled conditions.

Cutting out sections for pipes, wires and ducts is only permitted in accordance with the manufacturers instructions. The following detail gives you an idea of the issues involved. We recommend that all alterations that do not fall within the manufacturers guidelines are referred for professional approval.

Floors
Minor cracks in concrete floors in garages and basements are not unusual and unless severe are seldom a structural issue. Concrete floors are mainly poured independently of the building structure and are therefore free to move and settle without affecting the structure itself.
Uneven wood floors are also not unusual, especially in older houses. There are circumstances however, where the slope of a floor may be an indicator of a more serious problem. Modern homes should have floors that are close to level.