The Gypsum

The GypsumConstructionHandbookffirs.indd 11/17/2014 12:07:53 PM

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The GypsumConstructionHandbookSeventh Editionffirs.indd 31/17/2014 12:07:54 PM

Cover design: WileyCover image: Courtesy of USGThis book is printed on acid-free paper. Copyright 2014 by USG Corporation and/or its affiliates. All rights reserved.Published by John Wiley & Sons, Inc., Hoboken, New JerseyPublished simultaneously in CanadaNo part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or byany means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permittedunder Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the CopyrightClearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, oron the web at www.copyright.com. Requests to the Publisher for permission should be addressed to thePermissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011,fax (201) 748-6008, or online at www.wiley.com/go/permissions.Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts inpreparing this book, they make no representations or warranties with the respect to the accuracy orcompleteness of the contents of this book and specifically disclaim any implied warranties ofmerchantability or fitness for a particular purpose. No warranty may be created or extended by salesrepresentatives or written sales materials. The advice and strategies contained herein may not be suitable foryour situation. You should consult with a professional where appropriate. Neither the publisher nor the authorshall be liable for damages arising herefrom.For general information about our other products and services, please contact our Customer CareDepartment within the United States at (800) 762-2974, outside the United States at (317) 572-3993 orfax (317) 572-4002.Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material includedwith standard print versions of this book may not be included in e-books or in print-on-demand. If this bookrefers to media such as a CD or DVD that is not included in the version you purchased, you may downloadthis material at http://booksupport.wiley.com. For more information about Wiley products, visitwww.wiley.com.Library of Congress Cataloging-in-Publication DataUSG Corporation.The Gypsum construction handbook / USG Corporation. — Seventh edition.pages cmIncludes index.ISBN 978-1-118-74984-5 (pbk. : alk. paper); ISBN 978-1-118-74981-4 (ebk);ISBN 978-1-118-74988-3 (ebk); ISBN 978-1-118-81919-7 (ebk)1. Gypsum. 2. Plaster. 3. Plastering. 4. Drywall construction. I. Title.TH8137.G8U84 2013691'.9—dc232013034149Printed in the United States of America10 9 8 7 6 5 4 3 2 1ffirs.indd 41/17/2014 12:07:54 PM

ContentsPreface xiTrademarks xiiEditorial Committee xiiUsing The Gypsum Construction Handbook xiiiWhat’s New xiv1Drywall and Veneer Plaster Products 1Gypsum Panel Products 2Products Available 5Exterior Gypsum Ceiling Board 8Gypsum Liner and Sheathing Products 14Roof Board Products 1617Floor Underlayment Products Suspended Ceiling Products 17Bead and Trim Accessories 22Framing Components 26Cavity Shaft Wall and Area Separation Fire-Wall/Party-Walls 2830Framing and Furring Accessories Sound Control and Insulation Products 33Firestop Products 34Fasteners 36Adhesives 4546Joint Compounds Concrete Finishing Compounds 51Reinforcing Tapes 51Veneer Plaster Finishes 54Primers 56Interior Texture Finishes 57Powder Texture Products 57Sound-Absorbing Plaster Finish 6060Ready-Mixed Texture Products Interior Patch and Repair Products 662Framing General Requirements Wood Framing Steel Framing Res ifpanels are to be screw-attached).5. Application of gypsum panels is not recommended over aninsulating blanket that has first been installed continuouslyc01.indd 31/17/2014 11:38:32 AM

4across the face of the framing members. Blankets shouldbe recessed and flanges attached to the sides of studs orjoists.6. To prevent objectionable sag in new gypsum panel ceilings,the weight of overlaid unsupported insulation should notexceed: 1.3 psf for 1/2″-thick panels with frame spacing 24″on center (o.c.); 2.2 psf for 1/2″ panels on 16″ o.c. framing (or 1/2″ USG Sheetrock Brand panels designed for sagresistance on 24″ o.c. framing); 2.2 psf for 5/8″ panels on24″ o.c. framing. 3/8″-thick panels must not be overlaid withunsupported insulation. A vapor retarder should be installedin all exterior ceilings, and the plenum or attic space shouldbe properly vented.During periods of cold or damp weather, where a polyethyleneor equivalent vapor retarder is installed on ceilings behind thegypsum board, it is important to install the ceiling insulationbefore or immediately after installing the ceiling board. Failureto follow this procedure may result in moisture condensationon the back side of the gypsum board, causing the boardto sag.Water-based textures, interior finishing materials and highambient humidity conditions can produce sag in gypsumceiling panels if adequate vapor and moisture control is notprovided. The following precautions must be observed to minimize sagging of ceiling panels:a) Where a vapor retarder is required in cold-weather conditions, care must be taken to avoid moisture condensation. The temperature of the gypsum ceiling panelsand vapor retarder must remain above the interior air dewpoint temperature during and after the installation of panels and finishing materials.b) The interior space must be adequately ventilated and aircirculation must be provided to remove water vapor fromthe structure.Most sag problems are caused by the condensation of waterwithin the gypsum panel. The placement of vapor retarders,insulation levels and ventilation requirements will vary bylocation and climate and should be reviewed by a qualifiedengineer if in question.7. Certain recommendations regarding surface preparation andpainting products and systems must be adhered to for satisfactory performance and intended results.8. Precaution should be taken against using gypsum panels as abase for highly water-vapor-resistant coverings when the wallalready contains a vapor retarder, as this will create a doublevapor retarder. Moreover, do not create a vapor retarder bysuch wall coverings on the interior side of exterior walls of airconditioned buildings in hot-humid climates where conditionsdictate a vapor retarder be located near the exterior side ofthe wall. Such conditions require assessment by a qualifiedmechanical engineer.c01.indd 41/17/2014 11:38:32 AM

Drywall and Veneer Plaster Products5Products AvailableUSG Sheetrock Brand UltraLight Panels 1/2″ Up to 30% lighterthan regular 1/2″ wallboard, these are the lightest 1/2″ gypsum panels available. The panels offer superior sag resistance and can replace1/2″ sag-resistant ceiling board and ″ Type X on ceilings with 24″o.c. frame spacing. This can reduce waste as only one type of panel isrequired for walls and ceilings. Available with tapered or smooth walledges and 48″ and 54″ widths.1USG Sheetrock Brand Regular Core These 48″-wide panels havelong edges tapered on the face side to form a shallow recess (nominal0.050″ deep) to accommodate joint reinforcement. Made in threethicknesses for specific purposes: 1/2″, recommended for single-layer application typicalnew construction and remodeling. The thickness provides resistance to fire exposure, sound transmission andsagging. 3/8″, lightweight, applied principally in repair and remodelwork over existing surfaces. 1/4″, lightweight, low-cost, utility gypsum panel, used as abase layer for improving sound control in multilayer partitionsand in covering old wall and ceiling surfaces. Also used forforming curved surfaces. Meets ASTM C1396.USG Sheetrock Brand 54″ Gypsum Panels Available as 1/2″regular and lightweight USG Sheetrock Brand gypsum panels but6″ wider. The added width reduces cutting, waste, joint finishing andlabor costs for walls that are 8′–6″ or 9′ tall.ConventionalSWTypes of tapered edgesUSG Sheetrock Brand Gypsum Panels, SW Feature an exclusivetapered rounded-edge design to help minimize ridging, beading andother joint imperfections. This edge produces a much stronger jointthan a regular tapered edge when finished with joint treatment. Exceptfor the rounded edge, panels are tapered like, and otherwise identicalto, regular tapered-edge gypsum panels. Made in 5/8″ and 1/2″thicknesses. Panels are available in regular or Firecode Core (Type Xand Type C) formulations. Meets ASTM C1396.USG Sheetrock Brand Firecode Core 5/8″ thick, combine allthe advantages of regular panels with additional fire resistance—theresult of a specially formulated core containing special additives thatenhance the integrity of the core under fire exposure. Panels comply with ASTM requirements for Type X gypsum board. Meets ASTMC1396. Also available 54″ wide.USG Sheetrock Brand Ultralight Panels Firecode 30 A lightweight 5/8″-thick non-Type X panel that is up to 30% lighter thanstandard Type X wallboard. Ideal for use where 5/8″ panels aredesired for added strength, but Type X is not required for fire or soundratings. Meets or exceeds ASTM C1396 physical properties for 5/8″wallboard. Available with tapered ed

6 Finishing Veneer Plaster Systems 205 Advances of Veneer Plaster 206 Veneer Plaster Finishes 206 Applying Trim Accessories 208 Joint Treatment and Surface Preparation for Veneer Plaster Construction 213 Veneer Plaster Finish Applications 215 Painting Veneer Plaster 221 Radiant Heat Plaster System—Diamond Veneer Finish 222