There is a stair-step crack over your window

The steel over the opening

A window, a door and a garage door each leave a gap in the brick. Something has to carry the wall above that gap. In some brick houses it is a steel angle called a lintel, laid across the top and hidden behind the face.

You usually cannot see it. What you can see is what it does to the brick around it. Walk around the house and look at the top of every opening, and write down which ones show a crack.

How rust lifts brick

Bare steel exposed to water rusts. Engineers at an architectural engineering firm note that rust scale can swell to as much as 10 times the size of the steel it grew from. That swelling has no place to go but into the masonry above, which gets pushed up.

The trade calls this rust jacking. The push opens joints near the opening and pulls the brick apart in a line. Ask the mason whether they see rust, and where the water gets to the steel.

The three signs that point to the lintel

First, a crack that climbs from the corner of the opening in steps, following the joints. Second, a rust stain on the brick or the mortar below or beside the joint. Third, a row of brick over the opening that no longer sits level.

Any one of these is a prompt to look closer. All three together make a strong case for asking a mason about the lintel. Take photos of each, wide and close, and keep them with a date.

Why filling the crack can backfire

If rust is pushing the brick, the crack opens again. Filling it hides the sign and seals water in, so the steel goes on corroding where no one can see it.

A crack can also be caused by something else, such as the seasons moving the wall. The Park Service advises tracking a crack across the seasons to see whether it is still moving. Mark each end in pencil, date the marks, and measure it every few weeks.

Flashing and weep holes

The Brick Industry Association calls for continuous flashing over the steel angle, between the steel and the brick, draining out through weep holes at the level of the lintel.

Ask the mason whether your opening has flashing and weep holes, and whether the repair will put them back. If they say it does not matter, ask them to explain why.

What the mason should tell you

You want to hear what the lintel is made of, how they found out, how much brick comes down, how the steel is treated, and how water will leave the wall afterward. You want the answers in the quote.

Quotes that only say crack repair leave the real decision out. Send us your photos and we help you get the repair priced by local masons. Put these questions to each one.

Older houses and hidden steel

Engineers say steel corrosion is a particular risk in masonry buildings from the early 1900s, where unprotected steel touches the exterior walls, and that it may be hidden inside the wall.

If your house is that old, look closely at the corners of your openings. Open the page for your town to see what its housing looks like, and mention the year to any mason who calls.

How Syracuse weather feeds the problem

Rust needs water, and the brickwork above an opening gets plenty of it. At the Syracuse airport, about 84 days a year bring a freezing night followed by a thaw, and the normal snowfall is 123.8 inches a year. Snow on a sill melts and runs into the joints around the steel.

Ask the mason where water is entering at your openings: the sill, the joints, the cracks or the gutters. Fixing the steel without fixing the water leaves the cause in place.

What to do this week

• Photograph each cracked opening, wide and close.
• Mark each end of every crack in pencil, with the date.
• Do not fill, caulk or paint over the crack.
• Note any rust stain, and any row of brick out of level.
• If a brick sags or slips, keep people and stored items clear of it.
• Send us the photos and the address.

Questions to put to each mason

1. What is the lintel over this opening made of?
2. How do you know, and what will you open up to see?
3. Is there rust, and how much steel is left?
4. How many courses of brick come down, and how are they tied back in?
5. Will flashing and weep holes go in, and where?

Write the answers beside each quote. A quote that cannot answer the first two has not looked at your opening yet.

When a crack is only a crack

Not every crack above a window comes from rust. Brick moves with the seasons, and some cracks open in the cold and close in the heat. Those are worth watching, not rushing.

The way to tell is time and measurement. A crack that stays the same size over a season, with no stain and no lifted brick, is a different case from one that grows or stains. Share your dated photos with every mason, so each one is working from the same record.

Garage doors and wide openings

A garage door leaves the widest gap in a brick front, so the lintel above it can carry a lot of brick. Cracks that start at the corners of a garage opening deserve the same attention as a window.

Check the brick above the garage door from the driveway, then from the side. Look for a dip or a rise in the courses, and send us a photo. Tell the mason that the opening is a garage, since the work is bigger and the price changes with it.

What a repair can look like

A mason who finds rusted steel has a few choices. The steel can be cleaned and coated, or replaced with a new lintel. Either way, the brick above usually comes down and goes back up level, with flashing under it.

Ask each mason which they would pick and why. Ask what they will do if the steel is thinner than they expected. The answer shows you whether they have a plan or only a price.

Basis: The Construction Specifier, Failures NPS, Common Problems with Brick Masonry