What a retaining wall tells you

The photograph came stapled to the slip: a concrete wall, waist high, holding the slope beside a driveway that climbs off one of the hill streets, its top edge tipped a shade out of plumb toward the pavement. Below the top course sat a row of weep holes, each one shadowed by a dark tongue of old seep. The reader is in escrow on the house at the top of the drive, the contingency period already running, and the general inspector has written the two words inspectors write when they want a specialist: further evaluation. The question on the paper is one line. Does a leaning wall matter?

The question, as filed

The slip carried one question in two clauses: does the lean matter, and is it the kind of finding that should slow a purchase down? Around it clustered the follow-ups the reader had not written yet but would. Which side of the lot line does the wall sit on? Did the city ever see a permit for it? Who pays if the honest answer turns out to be expensive? It went into the drawer reserved for walls, water, and the distance between the two, because that is where most letters from these hills eventually land.

What the file says before anything else

Start with the paper, because the paper is free. The ZIMAS parcel report from LA City Planning places the lot: zoning, hillside status, whether the Highland Park-Garvanza HPOZ reaches it, which matters for anything visible from the street. The county assessor's roll gives the year the house was built and the lot as recorded, though walls rarely appear there as line items; improvements of that scale were seldom enumerated on their own. LADBS holds the permit history for the address, and a wall with a permit has a birthday, a drawing, and sometimes a soils assumption attached. Once escrow opens, the preliminary title report lists the easements of record, and a drainage easement running along a wall line is worth knowing about before anyone argues over the wall itself. None of these documents says a word about condition. They say what the wall is on paper, and when the paper first noticed it.

How old is the wall?

Concrete tells its age if you know where to look. Board-formed walls, the horizontal lines of the lumber forms still reading in the surface, generally predate the mid-century on these hills, and the same decades that gave the streets their clinker brick chimneys gave the slopes clinker brick retaining walls, often raised by the same crews. A uniform poured wall with a raked gravel face is later. The assessor's year built brackets the house, not the wall, but on blocks developed in one push the two are usually close in age. Age alone is not the verdict. An old wall has finished whatever settling it was going to do, or it has not, and the difference is written somewhere else: in the water.

What is the water doing?

A retaining wall is a small dam with a hill behind it, and a dam without a spillway is living on borrowed time. The weep holes near the base are the spillway. Working holes announce themselves as clean staining on the concrete below, a dark streak a few inches long that has run the same path every rainy season of its life. The quiet ones are the worry: face dry, while the wall above shows a damp line, moss at the joints, or the white mineral bloom the trade calls efflorescence, which is salt the water carried out of the concrete on its way through. Then look uphill of the wall. A downspout discharging at the top of the slope, a sprinkler line, a planting bed watered daily against the wall face, each one loads the hill the wall is holding. The planted slope in the photograph does real work, roots holding the surface, but surface planting is not deep drainage, and deep drainage is the water that moves walls.

What does a lean actually mean?

Some lean is built in. Many walls were cast with a batter, a deliberate lean back into the hill, and a top edge running parallel to its base is geometry, not distress. The lean that matters is relative: the wall bellying at one spot, or the top drifting out while the base stays put. A porch post with its knee braces standing beside the drive makes an honest plumb line for comparison. Cracks read the same way. A hairline running vertically is often shrinkage from the original pour. A horizontal crack at mid-height, or a stair-stepped opening along the joints, is the wall narrating a load it is slowly losing an argument with. So is a joint that has opened where the wall meets the driveway paving. Motion is what the inspector is hunting, and motion needs a clock. A wall that tilted its inch sometime before the oldest photograph in the listing and then stopped is a different animal from one that has moved since the last rainy season. Visit twice, hold a string line along the face, and photograph it against something that stands still.

When does a wall become a question for the file?

The department draws its working line at four feet, measured from the bottom of the footing, and walls past that line want engineering and permits. Walls under it can still come in, because the question is not only height but load: a driveway above, a fence on top, a gate pier, or the bearing end of a sleeping porch upslope close to the wall line, and the arithmetic changes. That is the LADBS side. The planning side keeps its own folder, since inside the Highland Park-Garvanza HPOZ a street-facing wall can count as a contributing feature, so a repair that changes materials or profile may need design review before a permit, and the preservation plan is the sheet that says so. Inside escrow the practical answer is shorter. A general home inspector will describe the wall honestly and then defer it, because walls are read by geotechnical and structural engineers, and the contingency period is the window in which that reading is yours to order.

Where the record stops

The record has clean edges. It will not say who maintains a wall that sits near a lot line; title reports carry easements, not upkeep duties, and those live in negotiation, neighborly or otherwise. It holds no drawing for work done without a permit, and on these hillside blocks that describes a fair share of the concrete standing today. It cannot see the drains on the next parcel uphill, or whether anyone keeps them clear. The paper records what the wall is and when the paper noticed it; whether it is standing in ten years is answered by the wall, the water, and an engineer with a hand level. The desk reads the first half of that sentence. The second half belongs to no one in this building.

One walk worth taking

On the next rain, or with a hose running gently on the slope above, stand at the driveway and watch the weep holes work: which ones weep, which stay dry, how long the staining takes to dry afterward. Print the parcel report on ZIMAS and mark the lot line on it, ask at LADBS for anything ever filed on the address, walls included, and read the preliminary title report for easements before the contingency period spends itself. Walk the stair street at the bottom of the block while you are at it, because the public stairs are the neighborhood's other set of walls and they weather the same rains. Then have the wall looked at by someone whose letterhead says soils or structural, and keep the escrow number on every page you gather. A wall this old has already told most of its story. Rain is when it tells the rest.