Construction & Contractors/flagstone on dry cement

Advertisement

Expert: - 2/3/2008


Question
We are laying a flagstone patio and have heard from several sources that instead of laying the flagstone in premixed wet cement, to just use a thick layer of dry Portland cement.  You then place the flagstone on top of it and mortar in the joints.  The theory is that the Portland cement will harden thru the moisture in the mortar and through the ground moisture.  Do you know anything about this?  It appealing, because it would give me more time to place stones, but I'm wondering about how durable it would be.  Thanks

Answer
This is not an acceptable method. You have two choices: 1. Dry sand set, spread 3-4 inches of sand and rake smooth, set your flagstone on sand bed, and tap down to embed the stone in the sand. Once all pavers are laid, you fill joints with more sand and broom smooth.
2. Mortar set method. Use 1-1/2" to 2" masonry mortar as setting bed. Set flagstone in mortar and tamp down into place. Grout joint with same mortar.

Dry cement has the consistency of cake flour. It cannot properly support the stone.

I hope this helps.
Tad Dixon

Construction & Contractors

All Answers

Answers by Expert:

Ask Experts

Volunteer

Torin Dixon

Expertise

Questions concerning Natural Stone Fabrication and Installation including: Marble, Granite, Limestone, Slate, Soapstone, Bluestone, and Travertine in Slabs and Tiles. Expert in natural stone cleaning, sealing, protection and restoration. Distributor of HMK Stone Care Products; Sealers, Cleaning Products, Stone Maintenance. Expert in stone and tile flooring, sealing and maintenance issues. Stain removal from stone. Importer and Distributor of slab stone for residential and commercial applications. Stone carving Stone restoration

Experience

I have worked in the Dimensional Stone Industry since 1977.
California Contractors License 1989
Former owner of Prestige Marble & Tile (So. Calif.)
Current owner of Elegance in Stone (Missoula, MT)
Current Owner of Montana Stone Gallery,LLC Missoula, MT
Owner of Stoncareonline.org Distributor of natural stone maintenance products

Organizations
Missoula Building Industry Association
Montana Building Industry Association
Flathead Building Association
National Association of Home Builders
Member of the Marble Institute of America
Former member of the National Tile Contractors Association

Publications
Slippery Rock Gazette-Stone Industry Publication

Education/Credentials
Journeyman Marble Mason, Bricklayers and Allied Craftsman Union #2
California Contractors License 1989-1997
Montana Contractors Registration #42969
Importer of natural stone slabs. Owner-Director of Montana Stone Gallery a regional Importing and Distribution company located in Missoula, MT

Past/Present Clients
Thousands of commercial and residential installations of stone slabs and tile in bathrooms, kitchens, showers, flooring, fireplaces over a 34 year professional career.

©2012 About.com, a part of The New York Times Company. All rights reserved.