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Renovation & Design

ASK THE INSPECTOR: Settlement, workmanship can create cracks

QUESTION: Ari, I hope you can help me with a problem. A number of hairline cracks are appearing in the ceiling of our 1,500-sq.-ft. bungalow. The cracks are found in the foyer, living room, kitchen and nook, which is open-concept in design. They follow the Sheetrock's length-wise edges. It started with one a few years ago. More are appearing over time.

The home was built in 2004, so it is constructed using relatively new technology. The roof trusses are built on 24-inch centres and OSB was used to sheet the roof. I see no signs of movement in the basement or elsewhere in the house. A string along the bottom of the support beam does not show serious deflection. Humidity is controlled at 40 per cent or so during the winter.

Is there something I should be doing? What would be the best repair so the problem does not reoccur?

Thanks, D'Arcy Keast

ANSWER: The cause of ceiling and wall cracks in homes, especially newer ones like yours, can be attributed to either settlement or workmanship issues. Since you feel there is little sign of movement in the home, the obvious conclusion is original construction defects. I will suggest possible repairs and offer a plausible explanation for the phenomenon.

The term settlement is often used in regard to buildings to describe sinking or movement. This occurs in many buildings due to changes in soil conditions over time. Some areas have minimal problems with settlement, due to sandy or other favourable soil conditions and others such as ours can have major issues.

Because we are living in a historic flood plain known as the Red River Valley, our soils are highly subject to movement. This is due to thousands of years of flooding of our rivers, which have deposited multiple layers of silt and expansive clay soils in our region. These clay soils will expand and contract with changes in moisture levels and temperature. This will often cause many homes, built on traditional spread footings, to move or sink, especially after initial construction.

To solve this issue, many newer home foundations are built on deep-poured concrete piers, which prevent movement due to soil expansion and contraction. The fact you have seen little movement in your home leads me to conclude your home is built in this manner or you are otherwise fortunate.

Many, many homeowners have observed cracking, similar to yours, in their walls and ceilings over the past year due to back-to-back dry summers. The soil may have contained less moisture than in several years and subsequently shrunk considerably. This even occurred in older homes, which had been more or less stable for decades. While you may not have been able to observe this in your telepost measurements, if your home is built on a footing, some settlement may have contributed to the cracks. While this is probable, I still think your problems began with initial construction.

When homes are currently constructed, the underside of the roof trusses are covered with thick polyethylene sheathing, which provides an air/vapour barrier for the top of the building envelope. This prevents excessive warm-air intrusion into the attic, which can cause major moisture issues if not installed.

The difficulty with this sheathing is it must be overlapped and caulked at seams, protrusions and the junction with the exterior wall air/vapour barrier. With today's complicated floor and roof plans, this may lead to bunching of this plastic sheathing in several areas.

Because of this, it can be difficult for contractors installing the drywall on ceilings to properly secure the individual panels to the trusses while maintaining flat surfaces. This can cause small gaps between the drywall and the trusses and poorly secured fasteners. This is particularly true in large open-concept areas, like your home, where drywall sheets may be 12-to-14 feet in length.

Compounding the problem of proper fastening of ceiling drywall are the large amounts of insulation that are now being installed in the attics above. While this insulation is very light and fluffy when installed, adding minimal weight to the ceilings, over time it may become heavier.

Some types of insulation can absorb moisture from other building materials or frost buildup in the attic, particularly in the springtime. This can cause poorly secured areas of drywall to move slightly, and can also recede in the warm summer months as the attic dries out. This can cause drywall screws to "pop" or push out drywall compound that covers their heads. It can also cause drywall tape and seams to open, which is likely what you are observing.

As I said earlier, the likely cause of your ceiling cracks is original workmanship. This may be from poor securing of the drywall sheathing, as discussed, or sloppy application of drywall tape and compound at the seams.

A poor-quality taping job may not be noticeable at the time of possession, but may become more visible as the house ages and building materials dry out, shrink or move. If you have a flat ceiling not covered by stipple or other coatings, hairline cracks may be all the more visible.

The solution is to hire a reputable drywall contractor to properly secure the ceiling followed by taping and painting the damaged areas.

While this explanation may seem oversimplified, it's quite a common occurrence, which will likely not reoccur once properly repaired.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors -- Manitoba (www.cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at www.trainedeye.ca.

trainedeye@iname.com

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