Why are there cracks above my doors and windows?

The short version

Cracks above doors and windows are among the most common cracks in any house with drywall. The opening interrupts the board, and the corners of the opening are where the wall is weakest, so the wall's normal movement concentrates there. Most of the time that movement is small and harmless. Sometimes it is the first visible sign of something moving in the structure.

Why the corners crack

USG's drywall handbook describes the pattern. Field cracking "usually appears as diagonal crack originating from a corner of a partition or intersection with structural elements."^[1] The same entry says it "may originate from corners of doors, light fixtures and other weak areas in the surface created by the penetration."^[1] In other words, a crack running diagonally up and away from the corner of a door or window is what a wall under mild stress looks like.

What puts the stress there? The handbook's list for joint cracking is "often caused by structural movement and/or hygrometric and thermal expansion and contraction."^[1] A house swells and shrinks with humidity and temperature through the Virginia seasons, and the lumber inside it does too.

Framing above openings adds a second cause. The handbook names a board-fracture defect that comes from attaching panel directly to flat grain of wide-dimensional wood framing members such as floor joists and headers.^[1] The header is the beam over a door or window. Shrinkage of wood causes fracture of board.^[1] For door and window openings, the handbook points to control joints to minimize cracking: see Door and Window Openings on page 86 for use of control joints to minimize cracking.^[1] A wall built without that relief can crack at the same corners season after season.

Reading the crack

The crack alone rarely tells the whole story. Look at what comes with it:

• Probably cosmetic: a thin diagonal crack that appeared once, has not changed width in months, and is the only sign. It is more likely in a newer house still drying out, or after a swing in humidity.
• Worth a professional look: a crack that keeps widening or lengthening, reopens soon after being patched, or shows up at several openings at once.
• More worrying still: cracks together with doors or windows that suddenly stick or no longer latch, gaps opening between trim and wall, floors that slope or feel springy, or stair-step cracks in the brick or block outside.

Those last signs are why this answer is for a professional rather than a how-to. Telling normal movement from settlement or a failing header means looking at framing, foundation and drainage together, and a patch over a moving crack just hides the evidence.

Who to call in Virginia

Start with a licensed contractor who will come and look. DPOR says that if the work you are considering is valued at $1,000 or more, a valid Virginia Contractor’s License is required for the license category in which the contractor is to work.^[3] Unlicensed contracting is against the law.^[3] Under the Code of Virginia, a Class C contractor handles a single contract or project over $1,000 but less than $30,000,^[4] which covers many small repair jobs. Look the licence up on DPOR before you sign.

If the contractor suspects movement in the structure, expect a recommendation for a structural engineer or a contractor in the right specialty, and for a written scope that covers the cause and then the cosmetic repair.

Permits follow the nature of the repair. Patching and painting normally does not need one, but your local building office can confirm. Virginia's building code lists work that does, including installations or alterations involving (i) the removal or addition of any wall, partition, or portion thereof; (ii) any structural component.^[2] If the fix reaches framing, a header or the foundation, ask who pulls the permit. Our guide on whether you need a permit to replace drywall in Virginia covers the drywall side.

When to call a licensed pro

Call one before you do anything but watch the crack if:

• the crack is wider at one end, is growing, or has reopened after being patched;
• doors or windows near it have started to stick, rub or gap;
• there are cracks at more than one opening, or in the exterior brick, block or foundation;
• floors above or near it are sloping, bouncing or separating from the wall;
• you see water stains, soft board or mold near the opening, which turns it into a moisture problem. See how to repair water-damaged drywall.

If the cause turns out to be cosmetic, the repair is ordinary drywall work. See what a drywall patch costs in Virginia, read more home repair answers, or browse drywall patching pros.

When you are ready, describe the crack and where it is and licensed local contractors can quote a look.