How to Screed Concrete and Masonry

Screeding is necessary when pouring concrete for patios, garage floors, or walkways or for pouring gravel in preparation for laying pavers or other loose masonry units.

Screeding is more a technique than it is a tool—all you need is an old two-by-four, though an aluminum screed works best.

Learn the basics of how to screed concrete or how to screed sand and gravel for masonry units.

What Screeding Is

Screeding is the smoothing of any pliable material into a flat, smooth, and level layer.

Screeding also redistributes and removes excess material. With concrete or masonry, screeded excess is mainly pushed to the front, but some screeded excess falls off the sides of the form.

There are tools manufactured expressly for screeding, but you can also make use of any straight board to do the job.

How to Screed Concrete

With concrete work, screeding flattens just-poured concrete into a reasonably smooth, flat layer before finishing the surface.

Screeding is not the final finish. While screeding fills large gaps and removes high spots in the concrete, the surface is still rough and unfinished.

Finishing is the work of the bull float, a long-handled tool with a smooth, broad metal head. The float draws fine aggregate and cement up to the surface of the slab.

Concrete Screed Tools

Use an old two-by-four, an aluminum screed, or a vibratory screed:

• Two-by-four: Any two-by-four that spans the concrete form can be used for screeding.
• Aluminum screed: An aluminum screed is an improved version of the two-by-four. It has similar dimensions, but it is lighter, easier to handle, and has sharper edges and smoother faces.
• Vibratory screed: For more professional, faster screeding action, a motorized concrete vibratory screed may be used.

Screeding Concrete

The screeding tool is generally long enough so that the ends can rest on opposite sides of the concrete form. The screed is drawn toward the workers with a sawing, scraping motion that simultaneously smooths the surface and pushes excess concrete into any gaps or voids.

It helps to have two workers, one on each side of the screeding tool, especially for large slabs. Aluminum ​screeds are often used where precision is needed, as they provide a straighter edge.

How to Screed a Masonry Base

Screeding masonry base is the flattening out of a layer of mortar, sand, or gravel underlayment beneath a surface in preparation for laying pavers.

In this context, screeding is done to help an upper layer (concrete pavers, stone, or brick) rest firmly on a smooth, flat layer.

Masonry Base Screed Tools

A two-by-four is often used as a screed for DIY walkway projects. The sand/gravel surface is more forgiving than the concrete surface. Minor imperfections will be covered by the masonry units.

One trick to keep screeding consistent is to lay out 1-inch PVC pipes before dumping the sand. As you screed the sand across the pipes, the pipes act as guards to prevent you from screeding any deeper.

Screeding Masonry Base

For masonry items like bricks or pavers, a layer of 1-inch coarse bedding sand is first dumped and shoveled evenly across the area. Since this is the last bedding layer before laying the masonry product, it's important to get this as smooth and perfect as possible.

After screeding, carefully remove the PVC pipes and fill in the depressions with loose sand. It's always a good idea to trowel the loose sand to smooth out the filled-in areas.

Screeding Concrete or Masonry With an Assistant

Working with an assistant is critical for perfect screeding. If not, you're pulling the screed behind you with concrete screeding or you're kneeling in the sand layer when screeding masonry base.

The screed tool will help to smooth out your knee and shoe depressions, but not entirely. So, it's best not to kneel in the sand in the first place. When you work with an assistant, both of you can remain outside of the project area, on either side.

In addition, screeding tools can be hard to handle. Screeding a 3-foot-wide walkway is manageable by one person. When the screeding tool is a full-length two-by-four (8 feet or even longer), it is very difficult for one person to effectively handle the tool. You'll need two people—one at each end—to control this heavier, larger tool.