Cracks in vaulted ceiling likely drywall issue

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This article was published 20/08/2011 (5155 days ago), so information in it may no longer be current.

QUESTION: I live in a five-year-old house with a cab-over design. The owner before me said the house was built on piles, but I have noticed a long crack on the ceiling exactly in the middle of the stipple ceiling in the vaulted area. Perhaps it was there last summer but was not so visible. During the winter it was very visible. What should I do? Tony Bhola

ANSWER: I can’t begin to count the hundreds and hundreds of times I have had this question about ceiling or wall cracks asked by clients during home inspections.

It is easily the most common question, due to the nature of plaster and drywall, which will crack for dozens of reasons in almost any age of home. What you should do about this issue in your home is don’t panic.

That is the first order of business while I attempt to explain what is happening in your home.

For those not familiar with the terminology, a cab-over style home is one that has a partial upper floor built partially or totally over an attached garage. These are often split-level or expanded bungalows with one or two rooms, normally the master bedroom with ensuite bathroom, added to the front of the home.

Because of the added height of the upper room, the ceiling is often vaulted in the adjacent living space, which may include a great room or living room and kitchen area. These vaulted ceilings are normally the underside of specially designed roof trusses with the top of the truss a much steeper slope at the exterior.

The higher, steeper roof meshes well with the roof of the cab-over section, which will have flat ceilings in the bedroom and bathroom areas.

It is important for me to explain this roof design because it is likely at the root of the cracks you are seeing. The crack you describe is at the apex of the vaulted area, which happens to be the highest point on the main-floor ceiling, but is also higher than the floor of the cab-over section.

Because of this height, there are large sections of drywall installed on the ceiling with multiple taped joints. The crack you are seeing is drywall tape or taping compound cracking, which may have one of several causes, but only one truly a concern.

The first and perhaps most prevalent cause of a crack at the drywall seam is poorly installed tape or compound. Inside corners of walls and ceiling can be the most difficult to tape if the drywall sheets are not perfectly square to each other and plumb. There are often gaps of varying widths along the joint between two sheets, which can make taping a straight line awkward.

If the taper is not very experienced at filling this gap and installing the paper drywall tape, imperfections can occur. This may include poor adherence of the tape, which is often seen later on as a straight line crack approximately one inch (2.5 cm) from the centre of the crack. This does not appear to be where your issue lies, so loosening tape may not be the problem.

The next possible culprit is in the installation of the drywall, itself. As you can imagine, it can be quite difficult to properly secure very lengthy sheets of four-foot-wide drywall to the underside of a vaulted ceiling, which can be six or seven metres above the floor at the peak. Compound this with bunched up or tightly stretched polyethylene air/vapour barrier at this point, which can push the drywall sheets away from the trusses, particularly at the inside corners.

If the installers do not force the drywall up tight to the trusses when screwing in the sheets, a small gap may be left behind the drywall. With changes in humidity, or as the drywall compound cures, the drywall, tape or compound may shrink or expand creating the crack you are seeing.

As you have noticed, it may be very small or not visible in the summer when the relative humidity and temperature are highest and everything has expanded. As things dry out and cool in the winter, these items may shrink and enlarge the otherwise invisible fissure.

Another possible problem that can cause cracks at ceilings is movement in the floor system in the home. This is less likely if your home is built on concrete piers, commonly called piles, but can occur after a few years. Homes built on typical footings are often subject to seasonal movement, particularly at the middle of the home below the main beams.

This movement can push upward on the teleposts above the footings, forcing the main-floor walls upward. This can lift the roof trusses slightly, creating cracks at the ceiling. This is normally seen at the joint between the interior partition walls and the ceiling, not at the peak, but it can happen. What is more likely in a piled foundation is that the floor joists and walls shrink slightly over time as they dry out, sometimes creating small cracks in the walls of ceilings. These do not typically open and close but may if the shrinkage is minimal.

The final potential cause of the crack is a defect in the trusses or improperly secured roof or wall framing. This is the least likely issue and will almost always be noted by much more noticeable cracks that increase in severity over time. Your description does not match this scenario, which is why I caution against an overreaction on your part. While these kinds of issues do occur in newly built homes, they are rare and will also be accompanied by other more noticeable defects in other areas and components in the home. The probable solution to your cracks is hiring a good drywall contractor to check and secure the ceiling drywall by adding more fasteners followed by re-taping of the damaged seam.

The tough part is taping and repairing a stippled ceiling to match the existing finish, but it may be possible to partially scrape off the stipple if it were spray applied and should be doable by an experienced taper or painter.

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