Roof Sags

By Tom Feiza, Mr. Fix-It, Inc.,

During a home inspection, we check structural elements and consider basic standards. We look for movement, cracks, displacement, sags, pinched doors and windows, and sloped floors. While some roof sags are normal or “typical for age,” let’s look at a sagging roof that an inspector missed.

Inspecting the outside

For most ranch style homes, it is pretty easy to walk the lower slope roof or to look at the roof from the edge with a ladder. I prefer to walk it. While standing on the roof of this ranch home, I saw a potential sag (Photo 1). You can get a similar view from the ground, looking along the plane of the roof to the ridge. You will see a roof sag in the ridge, but you might not see the sag in the valley.

Visible Roof Sag

A closer view from the roof confirms the sag (Photo 2). You can see the dip at the top of the metal valley. The shingles look displaced and don’t align horizontally. There is also a visible dip in the roof adjacent to the valley.

Roof Sag Closer Look

Checking the attic below the sag

Remembering where the sag is located, let’s look in the attic. Wow! Some homeowner made a creative attempt at structural repair (Photo 3). The jack, supported by a plank on the ceiling joists, lifts the framing along the valley. Someone sistered a 2 by 4 to the framing, but it provides very little structural support for the large, visible crack in the framing.

Creative Structural Repair

Maybe the hydraulic jack was forgotten in the attic, or maybe jack was “designed” as part of the structural repair?

Look below the jack and framing

The garage below the jack has a drywall-finished ceiling (Photo 4). Joints in the ceiling are opening up. In fact, it looks like the drywall joints were patched and painted, and then they cracked again.

Gagage Celing Below Jack

The garage ceiling framing was designed to support the drywall. The jack lifting the roof structure sag has displaced the garage ceiling – the framing was not designed to lift the roof.

The takeaway

How did the original inspector miss this visual defect? I assume it’s due to completely ignoring the attic. The cracks in the garage ceiling drywall might be typical for a 1970’s ranch. The sag in the roof is a little hard to see. But the hydraulic jack in the attic and the amateur repairs – these are easy to see, and definitely a defect to be reported.

Always look for roof sags. Follow any significant sags to the framing and the attic below. If the sag is minor, it just might be typical for the age of construction.

Weather Tight Corp

Tom Feiza has been a professional home inspector since 1992 and has a degree in engineering. Through (, he provides high-quality marketing materials that help professional home inspectors educate their customers. Copyright © by Tom Feiza, Mr. Fix-It, Inc. Reproduced with permission.

To learn more, attend Tom’s technical presentations at educational sessions for ASHI chapters and local groups. Tom can also provide his knowledge for your educational event; contact him at

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