Contractor How-To: Patio Overlay on Concrete Slab

Get the details of exactly what you should do before starting a patio overlay on a concrete slab. We are using ICPI's technical guides for this topic. 

How-to: Patio Overlay on Concrete Slab

This is an except from ICPI's full technical guide. To read the entire document for full details, click here to download the guide. 

1. Select your bedding and joint sand.

- Washed, clean, ASTM C 33, washed concrete sand, non-plastic, free from debris, symmetrically shaped, natural or manufactured from crushed rock.

- Do not use limestone screenings, stone dust, or mason sand C 144 for the bedding sand.

2. Prep your site.

- Base needs to be clean and dry.

- Verify that base is ready to support sand, edge restraints, pavers and imposed loads.

3. Install your edge restraints.

- Install edge restraints per the drawings and manufacturer’s recommendations.

4. Installation of the pavers.

- Spread bedding sand evenly over the base and screed to a nominal 1 in. thickness. Spread bedding sand evenly over the base course and screed rails, using the rails to produce a nominal 1 in. thickness, allowing for specified variation in the base surface.

Note: When initially placed on the bedding sand, manually installed pavers often touch each other, or their spacer bars if present.

- Lay pavers in pattern(s) shown on drawings. Place units hand tight without using hammers. Make horizontal adjustments to placement of laid pavers with rubber hammers as required.

- Fill gaps at the edges of the paved area with cut pavers or edge units.

- Cut pavers to be placed along the edge with a double blade paver splitter or masonry saw.

- Keep skid steer and forklift equipment off newly laid pavers that have not received initial compaction and joint sand.

5. Compact and sand your project.

- Use a low-amplitude plate compactor capable of at least minimum of 4,000 lbf  at a frequency of 75 to 100 Hz to vibrate the pavers into the sand. Remove any cracked or damaged pavers and replace with new units.

- Simultaneously spread, sweep and compact dry joint sand into joints continuously until full. This will require at least 4 to 6 passes with a plate compactor. Do not compact within 6 ft  of unrestrained edges of paving units.

- All work within 6 ft.  of the laying face must shall be left fully compacted with sand-filled joints at the end of each day or compacted upon acceptance of the work. Cover the laying face or any incomplete areas with plastic sheets overnight if not closed with cut and compacted pavers with joint sand to prevent exposed bedding sand from becoming saturated from rainfall.

- Allow excess joint sand to remain on surface to protect pavers from damage from other trades. Remove excess sand when done.

Need additional guidance for your next project? Just getting started in installing pavers?

Contact Jay, Andy or Mario from our Stone Team at 757-484-4421 or at stone@lancasterfarms.com. We are always here to help you!