Concrete Wall Cost Guide: Block vs Poured, With the Real Math

A concrete wall quote only makes sense once you know which kind of wall it is. A block wall and a poured wall are both concrete, but they are built differently, priced differently, and suited to different jobs. This guide does the math for both, so you can check any quote against your own numbers instead of trusting a single per-foot price.

The two kinds of concrete wall

A block wall is built from concrete masonry units, the grey blocks you see at every building site. Each block is laid by hand, mortared in place, and usually reinforced with steel bars and grout in the hollow cores. It is the common choice for garden walls, boundary walls, and garage walls.

A poured wall is concrete delivered by truck and cast inside wooden or panel forms, with steel reinforcement inside. It is one solid piece once it cures, which is why it is the usual choice for foundations, basement walls, and tall retaining walls.

The math starts the same way for both: measure the wall.

Step 1: Measure your wall area

For a straight wall, the area is simple:

Wall area = length x height

Take a 20-foot long wall that is 8 feet high as our running example:

20 x 8 = 160 square feet

Measure the gross area and do not subtract doors, windows, or gates at this stage. Openings still need lintels, extra blocks, and finishing work around them, so the gross number keeps your estimate honest. If your wall is L-shaped, measure each straight run separately and add them together.

Step 2: Block wall math

A standard concrete block measures 16 inches long by 8 inches high on its face. With a mortar joint, each block covers about 0.89 square feet, which means you need about 1.125 blocks per square foot of wall.

For our 160-square-foot example:

160 x 1.125 = 180 blocks

Then add waste. Blocks get cut at ends, corners, and around openings, and a few always break. Add 10 percent:

180 + 10 percent = 198 blocks, so buy 200

Mortar is the next item. As a rough rule of thumb, one 80-pound bag of mortar mix lays around 35 blocks, so this wall needs about 6 bags. Check the bag label, because coverage varies by brand and joint size.

Reinforcement matters too. Vertical steel bars are commonly placed about every 4 feet along a block wall, though your local code and the wall height decide the real spacing. For a 20-foot wall at 4-foot spacing, that is 6 bars, each as tall as the wall. If the cores are filled with grout, budget for that concrete as well, roughly 1 cubic yard for a wall this size.

Step 3: Poured wall math

A poured wall is priced by volume, not by area. The formula is:

Volume = length x height x thickness

An 8-inch thick wall is 0.67 feet thick. For our example:

20 x 8 x 0.67 = 107 cubic feet

Concrete is sold by the cubic yard, and there are 27 cubic feet in a cubic yard:

107 / 27 = 4 cubic yards

Add 10 percent for spillage, uneven ground, and form bulging, and you get 4.4 cubic yards, so order 4.5. Running short mid-pour is far more expensive than ordering half a yard extra, because a second truck delivery costs more than the extra concrete.

Formwork is the other half of a poured wall. You need forms on both faces, so form area is double the wall area:

160 x 2 = 320 square feet of forms

Most homeowners rent panel forms or buy lumber for the job. Either way, formwork is a real cost on top of the concrete, and it is the part people forget when they compare poured prices to block prices.

Step 4: Do not forget the footing

Every concrete wall sits on a footing, a wider concrete strip that spreads the weight. A typical footing for this wall might be 2 feet wide and 1 foot deep along the full 20-foot length:

20 x 2 x 1 = 40 cubic feet, or about 1.5 cubic yards

That footing concrete is separate from the wall concrete, and it applies to block walls and poured walls alike. If your quote does not mention a footing, ask whether it is included. Our concrete volume guide walks through the cubic-yard math if your footing size is different, and our concrete prices by mix guide explains what different mixes are for.

Step 5: Cost example with the numbers together

Prices change by region and supplier, so run this example with your own local prices. The rates below are examples to show the method, not quotes.

Block wall materials for the 20-foot example:

1. 200 blocks at 3 dollars each = 600 dollars
2. 6 bags of mortar at 10 dollars each = 60 dollars
3. 6 steel bars at 8 dollars each = 48 dollars
4. Grout for the cores, about 1 cubic yard = 150 dollars
5. Footing concrete, 1.5 cubic yards at 150 dollars per yard = 225 dollars
6. Block materials total = about 1,080 dollars

Poured wall materials for the same wall:

1. Wall concrete, 4.5 cubic yards at 150 dollars per yard = 675 dollars
2. Footing concrete, 1.5 cubic yards = 225 dollars
3. Steel reinforcement = about 150 dollars
4. Formwork rental or lumber = about 300 dollars
5. Poured materials total = about 1,350 dollars

Labour is where the two types split most. Block laying is often quoted per block or per square foot, while poured work is often quoted per square foot or per day for the crew. As an illustration only, at 10 dollars per square foot for block labour, this wall would be 1,600 dollars in labour, and at 15 dollars per square foot for poured labour, it would be 2,400 dollars. Replace those rates with the ones your contractors actually give you, and compare quotes on the same wall area, same height, and same footing, or the comparison means nothing. If you are still weighing the concrete itself, our concrete cost guide and our bags of concrete guide cover the bagged-versus-truck decision.

Which one should you pick

For a low garden or boundary wall, block is usually the practical choice. It needs no formwork, it can be built a little at a time, and a careful DIYer can do a low wall. For a basement wall, a tall wall, or a retaining wall holding back soil, poured concrete is usually the better engineering choice because it is one solid piece with continuous steel.

One warning that applies to both: retaining walls need drainage behind them, usually gravel and a drain pipe, or water pressure will push the wall over time. And any wall over about 3 to 4 feet tall, or any wall holding back a slope, is worth an engineer's look and a check of your local code before you build. That advice costs nothing and can save a rebuild.

Common mistakes that blow up the budget

1. Ordering exact quantities with no waste allowance, then paying for a second delivery
2. Forgetting the footing, which is 1.5 cubic yards of concrete on its own in this example
3. Comparing a block quote that excludes grout and steel to a poured quote that includes everything
4. Skipping drainage behind a retaining wall and paying for the repair later

The honest formula for the whole job is simple: wall area first, then blocks or cubic yards, then footing, then forms or mortar, then labour on the same basis. Do it in that order and no quote can hide much from you.