Crack Where Ceiling Meets Wall
  1. Hairline Crack Where Ceiling Meets Wall

A crack is continuous though the wall and ceiling. Ceiling cracks that run across the ceiling to the wall and then downward on the wall; basically a continuous crack going through the ceiling and the wall. This type of crack suggest that there may be a structural issue, i.e. A foundation issue or framing issue. We purchased our townhome in Northern Virginia in 2014 and recently started noticing some cracks where the ceiling and wall meet. The house was built in 2009 and is three stories tall. All of the cracking appears to be occurring on the top level of the townhome, primarily in the master bathroom and one of the other bedrooms.

Have attached photos of the beam and the cracks where it meets the wall on both ends, thanks! The last image is from far away sorry, its a double height space.But they are hairline cracks on one vertical side of the beam and continuing below it for maybe a foot, as well as under it running horizontally. A cracked wall could lead to a more extensive repair if it’s not fixed at once. The best way to remedy a crack on the wall is to put a joint compound. The joint compound is a kind of putty designed to fill the cracks on concrete. It is strong enough to stay between cracks and prevent the concrete from dirt and anything that could cause more cracks. Have attached photos of the beam and the cracks where it meets the wall on both ends, thanks! The last image is from far away sorry, its a double height space.But they are hairline cracks on one vertical side of the beam and continuing below it for maybe a foot, as well as under it running horizontally. Large crack where ceiling meets wall Cracks develop when attic trusses lose moisture and bow Fix with inexpensive L-brackets Caulk to complete DEAR TIM: I think my house might be falling down. In the past few weeks, a large crack has formed where the ceiling meets the walls in my home. Drywall cracks in ceilings or walls: This article describes the common causes of all types of cracks that appear in drywall or gypsum board or plasterboard walls & ceilings in building interiors. Illustrations show where cracks are most likely to appear, explain why, and suggest both repair approaches to drywall cracks and how to prevent cracking in plasterboard or gypsum board.

  • POST a QUESTION or READ FAQs about plasterboard cracks, drywall cracks, gypsum board cracking & movement

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Drywall cracks in ceilings or walls:

Where, when & why does drywall crack? Coefficients of thermal and moisture expansion & contraction or movement for gypsum board products.

This article describes the common causes of all types of cracks that appear in drywall or gypsum board or plasterboard walls & ceilings in building interiors. Illustrations show where cracks are most likely to appear, explain why, and suggest both repair approaches to drywall cracks and how to prevent cracking in plasterboard or gypsum board.

Photo at page top: severe settlement cracks around windows in an Alaskan home. Soil, foundation, and frost problems were causing severe ongoing movement in this structure.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Causes & Types of Cracks in Drywall, Plasterboard, Gypsum Board Walls & Ceilings

Article contents - Causes of drywall or gypsum board cracking, sorted by categories

  • DRYWALL CRACKS
    • TRUSS UPLIFT, ROOF - separate article

Gypsum Board Installation Error contribution to gypsum board cracks & damage

Drywall installation snafus: poor support or connections, over-cuts with a drywall knife at corners of openings, failure to provide for seasonal or other variations in temperature & moisture, improper joint finishing, possibly omission of drywall tape at some gaps, cracks, or repairs.

Drywall movement control joints omitted on long drywall runs in ceilings (sketch at left) or walls, distances over 30 ft. Control joints may also be needed at common ceiling or wall stress points such as at 'L', 'T', 'U' or 'I' shape ceiling or wall intersections like those shown in our sketch above.

See DRYWALL CONTROL JOINTS
[Click to enlarge and show detail for any image]

Drywall tape type used for corners: do not use mesh type drywall tape in building corners nor at ceiling/wall joints. It may be easier to install than paper tape but it is not as strong and is more tear-prone.

Long runs of continuous drywall, especially if more than 30 feet or about 10 meters in its long dimension are likely to suffer expansion/contraction cracking and possibly ridging if control joints are omitted.

Our drywall ceiling photographs above and below show a continuous ceiling that runs the length of this home, or 64 1/2 feet in total distance.

The ceiling width is interrupted near one end by the distant partition wall you can see in the left hand photo, but the ceiling continues to open up into another room at that end of the house.

The ceiling crack shown in our photograph at above right occurs almost in the center of this long ceiling run. Seasonally as temperatures and humidity vary the width of this ceiling crack also changes from close to hairline (warm humid summer months) to nearly 1/8' in width (cold dry winter months).

Using the coefficients of thermal and moisture expansion and contraction in drywall found at PLASTERBOARD EXPANSION COEFFICIENTS, and with a 'ballpark' estimate of seasonal temperature variation of 20 degrees and relative humidity variation of 30%,

we calculate that the total expansion or contraction range force over this ceiling length (744 inches) is about 0.138' (thermal) and 0.145' (moisture) for a total of about 0.28 or 3/10 of an inch - more than a quarter of an inch - more than enough to cause a huge ceiling crack.

Why do we see that the actual ceiling crack is not nearly this wide?

Because the 744 inch long ceiling is not unrestrained while the coefficients of thermal and humidity expansion and shrinkage are for unrestrained gypsum board. This ceiling's gypsum board is nailed to the underside of flat roof rafters spaced 16' o.c., distributing much of the thermal and humidity-related expansion and contraction forces over a large area.

Still we see an ugly wintertime crack in this ceiling and a noticeable summertime crack as well. There is not much point in just taping over this crack without installing control joints in this ceiling.

Metal corner beads are more crack and separation prone in drywall installations than plastic tape-on or glue-on (using spray adhesive) or mud-on corner bead material.

Building foundation settlement, frost heave, foundation drainage contributions to gypsum board cracks & damage

Frost heaving foundations can cause differential movement in building walls that causes severe tearing or cracking in plasterboard, gypsum board, or drywall.

Photo above left: shear cracking shows up at the inside drywall corner of two exterior walls of a New York building.

This cracking was caused by differential frost heaving. At above right you can see the corresponding crack in masonry block foundation supporting the building walls. High soil water content, drainage difficulties, and freezing climate explain this damage.

See FOUNDATION CRACKS & DAMAGE GUIDE

Building framing shrinkage & framing quality contribution to gypsum board cracks & damage

Framing shrinkage & other snafus: using wet lumber, pressure treated and still wet lumber, or poor quality framing connections that permit movement and settlement that can in turn lead to drywall cracks, tears, or drywall joint tape separation.

In a demonstration that the ceiling crack stress point sketch is not just theory, our photos just above show cracks at the taped intersection of ceiling to partition wall at a natural stress point. This crack appeared in less than a year after new construction.

The underlying cause may have been a combination of framing shrinkage and slight sagging of the supporting floor structure.

The wall corner projecting into the room is directly above a stairwell cutout. Floor settlement actually pulled this corner down, separating it from a rigid I-beam roof structure.

We will repair this crack by cutting out the separated paper drywall tape and re-taping the joint on both sides of the partition wall corner-to-ceiling juncture. But this little repair is a bit of trouble as re-painting the ceiling and wall will also be needed. In my OPINION (DF) this is normal new construction cracking that is difficult to prevent.

Our photo at left shows the original drywall being installed on the same ceiling as in the drywall tape joint separation photographs above.

You can see that the sheetrockers took care to hang a full piece of drywall that extended past the partition wall corner precisely because they knew that this was a stress point.

That detail worked - we did not see a tear in the drywall itself. What did ensue was enough downwards movement to stress and open the drywall tape at the partition wall-to-ceiling joint.

Below is a second example of a similar effect. Here we see a complex soffit structure carrying windows and suspended from a conventionally-framed 2x12 ceiling structure. Here, too, cracks appeared in the ceiling as the structure below moved downwards.

[Click to enlarge the photo at left to see this drywall ceiling crack in more detail].

Framing flexing - drywall cracks: in interior ceilings or cathedral-ceilings not framed to modern construction standards for stiffness we may see cracks, often at drywall joints, caused by flexing in the ceiling structure.
Particularly in some older homes with minimal attic floor framing that was originally intended only to support the weight of a plaster ceiling, we may see ceiling cracks caused by building occupants (or home inspectors) who clambered around in the attic area above, stepping on framing members never intended to bear their weight.

  • Framing bowed, bent, uneven: installing drywall or gypsum board across uneven surfaces due to inconsistent or sloppy framing can add to material stresses that ultimately show up as plasterboard cracks.
    Such cracks are most likely to appear when a side joint or end butt joint appear over or close to a framing variation extremity.
    Use furring, cutting, trimming or similar measures to flatten out the install surface and to minimize these stresses, and avoid placing a taped joint over stress points.
  • Framing over-spanned: drywall installed at right angles to the supporting framing can span 24' (1/2' or 5/8' thick drywall) on walls, but on ceilings 1/2-inch or 5/8-inch drywall can span24 inches only if it is installed perpendicular to the joistsand supports less than 1.3 pounds per square foot (psf ) ofinsulation.
    Otherwise, 16-inch on-center spacing is recommended.With latex spray textures or airless spraying oflatex paints, perpendicular installation over 16-inch on centerframing is recommended to prevent sagging. - S. Bliss, Best Drywall Practices

  • Roof truss uplift: arching roof or floor trusses caused by moisture/temperature differences between truss upper & lower members. The truss uplift problem is less likely to occur in an interior ceiling supporting a floor above because both sides of the ceiling/floor structure are within conditioned space, making for more uniform temperatures and moisture levels across the truss.
    See TRUSS UPLIFT, ROOF for details.

Moisture or relative humidity variation contribution to gypsum board cracks & damage

Moisture or humidity variation: significant changes in the building moisture level or thus in the moisture content of plasterboard or gypsum board can cause expansion or shrinkage sufficient to produce a 1/16' wide or larger crack even if other forces are not in play.

Details of the coefficients of thermal expansion (or contraction) and the coefficients of moisture-related expansion and shrinkage of plasterboard are

at PLASTERBOARD EXPANSION COEFFICIENTS.

Structure or Foundation Settlement contribution to gypsum board cracks & damage

Settlement in buildings causes plasterboard cracks & tears: for any reason: framing shrinkage, foundation damage, site drainage problems, earthquake movement or slab settlement can cause significant gypsum board damage.

Below we give several examples of types of building movement traced to settlement and causing significant interior wall or ceiling cracking.

Backfill settlement in New York: the photographs below illustrate severe settlement in a New York home. Unlike the Alaskan house above (damaged by construction on thawing permafrost), the home below had been constructed on backfill over a stream bed.

Seasonal water flowing below the building appears to have contributed to severe slab and foundation damage that telegraphed upwards through this home as floor-wall separation, ceiling-wall separation, and cracks at windows and doors of the home shows in the photos just above.

By noting the plasterboard crack locations, patterns, angles, and dimensions it was apparent that they all pointed to settlement in the supporting slab.

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Checking the finished basement floor for level we confirmed that the floor was settling significantly towards the building center.

Permafrost settlement in Alaska: The two photographs above show severe plasterboard cracking in the same Alaskan home illustrated at the top of this page.

In the above photo, settlement and drywall tearing cracks appeared at a horizontal drywall joint to the right of a door jamb (a poor location for a drywall joint and exacerbated by the use of mesh tape that is not as strong or tear resistant as paper tape).
[Click to enlarge and see detail for any image]

In our second drywal cracking photo just above we see a typical diagonal gypsum board crack extending down and to the left of a window opening.

The window trim has been pulled apart as well. These cracks are not to be blamed on the drywall installation: this home had suffered movement in excess of what plasterboard is expected to endure.

This building is discussed in more detail

at SINKING BUILDINGS.

Earthquake damage to walls in California:

Earthquake damage crack patterns characteristic of the Northridge earthquake in California in January 1994 are illustrated by our photo shown at left.

This crack pattern appears here in a stucco exterior, but it was duplicated on drywall interiors as well.

Buildings suffering this extent of damage require structural repair or possibly replacement.

Details are

at EARTHQUAKE DAMAGED FOUNDATIONS.

Temperature variation contribution to gypsum board cracks & damage

Temperature variation: significant changes in the building interior temperature or thus in the temperature of plasterboard or gypsum board can cause expansion or shrinkage sufficient to produce a 1/16' wide or larger crack even if other forces are not in play.

Even if building temperatures are kept steady after construction is complete, drywall installation temperatures may contribute to subsequent cracks: mudding drywall in cold buildings increases drying times and may increase the crack risk.

Large variations in building temperature or moisture level or both. For example, leaving a building un-heated in a freezing climate or turning off air conditioning & dehumidification in a wet or humid climate.

See HUMIDITY CONTROL & TARGETS INDOORS

and also DRYWALL MOLD TESTING.
Details are at PLASTERBOARD EXPANSION COEFFICIENTS.

How to Prevent Drywall Cracks at Drywall Side or End Butt Joints

Use kiln-dried lumber for framing walls and ceilings. As Steve Bliss points out

at DRYWALL INSTALLATION Best Practices, ' With wet or poor-quality framing, there are bound to be problems in the drywall finish. With dry lumber and proper detailing, however, drywall problems can be kept to a minimum.'

Use drywall screws instead of drywall nails. Set the screws just below the drywall paper surface but not so deep as to cut through the paper.

When hanging drywall on a ceiling supported by the lower chord of roof trusses, review the suggestions

at TRUSS UPLIFT, ROOF, including using clips rather than screws or nails to secure drywall within a few feet of either side of building center partitions that run at right angles to the lower chord of the roof trusses.

The floating drywall corner method described

at INTERIOR FINISHES: BEST PRACTICES can also be used to float the ceiling drywall over the center partitions.

Inside corners at walls and between walls and ceilings are stress points for drywall and common places for cracks or nail pops. Leaving one side of the joint free to move without fasteners will eliminate most of these problems.

On ceilings, place the first screws 7 to 12 inches in from the corner and support the ceiling drywall with the wall panels. Also, do not fasten the top 8 inches of the wall panels.

No screws should go into the top plate, where shrinkage may occur. Similarly, leave one side unfastened at wall-to-wall corners, but make sure it rests against solid wood backing or drywall clips (see Figure 5-1).

Prevent Drywall Cracks Caused by roof truss (or on occasion floor truss) uplift

Nail pops found in some building ceilings and actual tears or cracks at the wall/ceiling juncture at building walls located under the center of certain roof trusses when moisture & temperature differences between the truss bottom chord and upper members cause the truss to arch.

Details and more illustrations of the roof truss uplift problem & more steps to prevent drywall cracking & nail pops are found at
TRUSS UPLIFT, ROOF

The drawings of roof truss uplift and corrective measures for truss uplift shown here are provided courtesy of Carson Dunlop Associates and appears in their Illustrated Home.

Also see CEILING FINISHES INTERIOR

and

see BEST INTERIOR FINISH PRACTICES

GRC: Gypsum Board Joint Ridging & Cracking

Drywall / Gypsum Board / Plasterboard Butt-Joint Ridging Causes & Prevention

As this article series discusses the expansion and shrinkage effects of drywall or gypsum board ceilings and walls (plasterboard in the U.K., Australia, New Zealand and other countries), we include this description of cosmetic damage caused by expansion rather than material shrinkage stresses.

GRC or gypsum ridging and cracking has been reported world-wide, with most writers commenting from Australia, Canada, New Zealand, the U.K. and the U.S. [1][2][4]

[Click to enlarge any image]

The Gypsum Association's definition of ridging is

Joint ridging, also called beading, is a uniform, fine line deformation occurring at gypsum board joints.

It is usually caused by compression of the edges or ends of the finished and decorated gypsum board resulting from the edges or ends being forced together from exposure to alternating periods of high and low temperature and humidity extremes due to thermal or hygrometric expansion. - [10] Repair of Gypsum Board Joint Ridging ( GA-221-00 )

Note: both ridging and cracking in gypsum board may both appear in the same installation.

For example, ridging may appear when forces (thermal expansion, moisture expansion) cause the material to expand, while cracks or tears may appear in plasterboard or gypsum board when the opposite site conditions (cooler temperatures and more dry conditions) cause gypsum board to contract.

OPINION: As we note below, many experts opine that the dominant forces in drywall cracking or tears are probably framing shrinkage and building movement - a view with which I agree. However gypsum board joint ridging is almost certainly going to be due only to expansion forces alone and would be expected to appear particularly at long runs of unrelieved (no control joints) drywall exposed to high moisture and high temperature or the two combined.

Suggestions for preventing gypsum board ridging include:

  • Inspect, document and correct building framing defects such as gaps, poor nailing or open framing joints before hanging the drywall.
  • Do not hang gypsum board on wet or pressure treated framed ceilings or walls without special design provisions such as the use of resilient channel supports.
  • Inspect, document, and correct site drainage, footing drain defects, building leaks and other sources of abnormal building moisture or of abnormal building movement, settlement, framing shrinkage.
  • Manage building & gypsum board humidity and temperature: Document the building humidity and temperature at the time of drywall application [and we recommend documenting as well the actual temperature and humidity level or moisture level of the drywall product being installed), and document abnormal variations in building temperature and humidity indoors beyond its design parameters.
    Gypsum board should be allowed to reach temperature and humidity consistent with the building interior where it is to be installed before it is hung or applied.
  • Additional measures to avoid ridging may include back-blocking or supporting at butt joints (extra cost, rarely used - DF)
  • Repair recurrent problem areas by supporting drywall on resilient channels
  • Use control joints at problem or stress points and in areas of drywall extending beyond 30 feet of unbroken or unrelieved panels.
  • See the SBCA's detailed recommendations at 'Gypsum Joint Ridging and Cracking' [1]

Question: how to repair cracked RhinoBoard

2017/08/31 Hennie said:

I have a flat roof and have problems with cracking and peeling ceilings. How do you repair it. It is Rhinoboard. Please help

Reply: first diagnose the cause of damage and decide if other building repairs are needed

Hennie,

Before suggesting a repair we want to know the cause of the cracking and we need to know (we meaning you mostly with some encouragement from the sidelines) if there is damage to the structure behind those cracks.

Otherwise a cosmetic repair may be wasted and a more-serious problem such as a leak, structural damage from loading, rot, or insects, may need to be repaired.

If you're using the RhinoBoard that's a product of GypRock Staint Gobain in South Africa (or similar) we're talking about a plasterboard that uses a foamed or aerated gypsum core bonded to paper liners: ivory coloured on one side and tan-brown on the other. Rhinoboard is non-combustible and is used on ceilings and walls.

Rhinoboard is sold square-edged and in tapered-edge formats, the latter making it easier to tape and plaster over joints before painting in what the manufacturer calls a monolithic finish as in the Gyproc Drywall System.

So you could remove peeled loose coating, skim coat the peeled areas with joint compound, then tape cracks and joints using a fibreglass mesh tape, then coat with joint compound out 18' wide across the crack to hide the damage.

But as I intended to emphasize that work would be wasted if we don't first diagnose the cause of the trouble you are seeing.

Besides cracking, the peeling could be telling us there are roof leaks to be found and repaired, and it could hint that there is a mold reservoir in the roof cavity. If I were repairing a Rhinoboard ceiling with those conditions I would

- make a test cut into the ceiling to inspect for water, leaks, mold, in the most-damaged, most-suspect areas.

- inspect the roof for leaks

- hold off on cosmetic repairs until those questions are answered.

If your Rhinoboard is suffering from recurrent cracks that have been repaired before, and if there are no building leaks above, then

see DRYWALL CONTROL JOINTS

Also see our discussion of drywall cracks and nail pops repairs

at DRYWALL NAIL POPS

If you want to send me photos of the condition for comment use the page top or bottom CONTACT link and I may have more specific advice I can offer. Also it would help to know the country and city where your building is located.

  • RHINOBOARD for CEILINGS, [PDF] Gyhproc Saint Gobain, 1 Shale Rd,N1 Business park,Intersection of Old JHB Rd and Tlokwa Street, Kosmosdal, Centurion, South Africa, Tel: +27 12 657 2800, Customer contact centre, 0860 27 28 29, Website: www.gyproc.co.za,or www.isover.co.za etrieved 2017/08/31, original source: http://www.gyproc.co.za/products/walls/rhinoboard
    RhinoBoard Square-Edge produced by Gyproc SA is a fire-resistant ceiling material with the following specifications, excerpted from the company's web page cited below:
    Subject to loading detail, suspension should not exceed 1200mm centres
    The suspension must not be out of plumb (vertical) more than 25mm for each 150mm of plenum depth and in no case should exceed 500mm to a 3000mm depth
    Whenever the above is exceeded and/or when the hanger suspension is more than 2000mm long, then a sub grid is recommended. Should suspension be vertical, then a 4200mm drop would be acceptable using hanger strap
    In no case should suspension be from other services in the ceiling void
    A hanger suspension point within 400mm from the wall angle or shadow moulding must be installed on main tees and cross tees
    Two steel pop rivets with a shear strength three times that of the maximum allowed ceiling load is to be used
    When securing wire to tee, it should be wound tightly around itself at least three times
    Should the ceiling mass exceed 20kg/m2, a sub grid is required and a consulting engineer should recommend suitable suspension
    - retrieved 2017/09/01, original source: http://www.gyproc.co.za/products/ceilings/rhinoboard-0
  • A distinctly different product, Rhino Board™, is a polypropylene honeycomb sheet made of cylindrical polyolefin tube straws bonded into a close-packed hexagonal matrix to produce a low bulk density material manufactured in a proprietary process by Rhinoboardwj, 2711 Karsten Court SE, Albuquerque, NM 87102 USA, Tel: (505) 842-5100, Email: info@rhinoboardwj.com, also distributed in Europe.
    A tpical use of this Rhino Board™ product is service as ' a lightweight and durable cutting surface for abrasive or straight sater jet cutting' . Website: http://www.rhinoboardwj.com/

..


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Technical Reviewers & References

  • [1] 'Gypsum Joint Ridging and Cracking', (2009), SBCA Tech Notes, Structural Building Components Association, 6300 Enterprise LaneMadison WI 53719, (608) 274-4849, (608) 274-3329 FAX, retrieved 12/11/2013, original source http://support.sbcindustry.com/images/technotes/T-GypsumInstallation09.pdf
  • [1a] Paul F. Schofield, Kevin S. Knight, Iona C. Stretrton, 'Thermal Expansion of gypsum investigated by neutron powder diffraction', (1996) Manuscript, retrieved 12/11/2013, original source: http://www.minsocam.org/msa/ammin/toc/ Articles_Free/1996/Schofield_p847-851_96.pdf
  • [1b] Azree Othman Mydin, 'Gypsum Board Thermal Properties Exposed to High Temperature and Fire Condition', (2012), University Sains Malaysia School of Housing Building and Planning, retrieved 12/11/2013, original source: http://www.ce.tuiasi.ro/~bipcons/Archive/325.pdf
  • [2] 'Gypsum Board Typical Mechanical And Physical Properties (GA-235-10)', (2010) Gypsum Association, 6525 Belcrest Road, Suite 480, Hyattsville MD 20782, retrieved 12/11/2013, original source: http://www.gypsum.org/wp/wp-content/uploads/2011/11/GA-235-10.pdf
  • [3] Drywall or plasterboard standards: ASTM D3678
  • Drywall or plasterboard standards: ASTM C1047
  • Drywall or plasterboard standards: ASTM D4216-99
  • Drywall or plasterboard standards: Canadian Codes [pending CSA citations]
  • ASTM C 473 specifies the maximum deflection in humidified gypsum board for interiors, for ceiling board, and for exterior gypsum soffit board
  • Drywall or plasterboard standards: ASTM C840
  • Drywall or plasterboard standards: ASTM C844
  • Drywall or plasterboard standards: Gypsum Association GA -216
  • Drywall or plasterboard standards: Gypsum Association GA -234 (Fire-Resistant Applications)
  • Drywall or plasterboard standards: Australian Standard AS2311–1992 for The Painting of Buildings (when painting plasterboard walls & ceilings)
  • [4] Boral Plasterboard (Australia), 'Boral Plasterboard Installation Manual', August 2007, PB103, Tel: 1800-811 222 (in Australia), Email: tecassist@boral.com.au, Website: www.boral.com.au, ACT: 7 Barrier St, Fyshwick 2609, Tel: 02 6280-4243. Other Boral Plasterboard offices are in New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, Western Australia, and the company has an export department.
  • [4a] Boral, 'Plasterboard Specifications', retrieved 12/11/2013, original source: http://www.boral.com.au/plasterboardexport/ plasterboard_specifications.asp
  • [5] British Gypsum Co., 'Gyproc Control Joint, Products Plasterboard Accessories', Website: www.british-gypsum.com.
  • [6] George M. Kutcher, Jr., 'Don't Overlook Control Joints in Drywall Construction', National Gypsum Company, Tel: 1-800-NATIONAL, www.nationalgypsum.com, retrieved 12/10/13, original source: http://www.nationalgypsum.com/resources/tech-talk-controljoint.htm
  • [7] National Gypsum Company, 'Gypsum Board Systems', 12th Ed., (2000), (Gold Bond® brand gypsumboard products), website: http://www.nationalgypsum.com
  • [8] George M. Kutcher, Jr., 'Don't Overlook Control Joints in Drywall Construction', National Gypsum Company, retrieved 12/10/2013, original soruce: http://www.nationalgypsum.com/resources /tech-talk-controljoint.htm
  • [9] 'Design Essentials for Controlling Movement Induced Stresses in Building Materials', Winstone Wallboards, Ltd., Winstone Gypsum, Dec. 2009, Winstone Wallboards Ltd 219 Opawa Road PO Box 1983 Christchurch New Zealand Phone: +64-3-332-3159, and Winstone Wallboards Ltd 37 Felix St PO Box 12-256 Penrose Auckland New Zealand, Tel: +64-9-633-0100, Email: gypsum@gib.co.nz, Toll free: 0800 475 475.
    Note: per Winstone: for large ceilings, AS/NZS 2589 specifies that all sheet end butt joints are backblocked (to reinforce the joint where such joints are not meeting over a ceiling joist). [This is a reinforcement detail for unsupported butt joints, not a wallboard movement control joint detail. The company's article does recommend that installers insert control joints at the junction of wallboard ceilings at hallways vs large open spaces - Ed. ]
    • Cracking and Building Movement, Dickinson & Thornton, 2006
    • BRANZ Bulletin 418 July 2001 ’Providing for Thermal and Moisture Movement’
    • Cracking and Building Movement, Dickinson & Thornton, 2006
    • NZS 3602 Timber & Wood Based Products for use in Building
    • Wood Processing Newsletter SCION July 2003 Simpson & Turner
    • ‘A Field Study of moisture performance of roofs etc.’ Technical Report 127. 1994 Cunningham et al
    • ‘Plasterboard Peaking and Cracking under Timber R oof Trusses’ 1999 - Prof H Robert Milner, BE, MEngSc, PhD, FIEAust, AIWSc and CY Adam, BE, MEngSC Monash Engineering Timber Centre, Monash University, Australia
    • ‘Walls & Ceilings’ Magazine ‘Drywall Cracking on a Global Scale’ By Greg Campbell March 9, 2001 ix AS/NZS2589 2007 – Gypsum Linings - Application & Finishing
  • [10] Repair of Gypsum Board Joint Ridging ( GA-221-00 )
  • [11] Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: ericgalow@gmail.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
  • [12] 'Finishing Drywall Systems', U.S. Gypsum (USG) Corporation [copy on file as USG_Finishing_Drywall_Systems_Ch5.pdf] 2009
  • [13] 'Sheetrock® All Purpose Joint Compound - Select for professional drywall finishing', Submittal Sheet 09250
  • [14] 'Quality Drywall Finishing in All Kinds of Weather', USG Folder J-75 (out of print), U.S. Gypsum corporation
  • [15] Gypsum Construction Guide, National Gypsum Corporation
  • [16] Gypsum Construction Handbook [purchase at Amazon.com] H17, Technical Folder SA920 and PM2, PM3 and PM4, United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124,
  • [16a] R.S. Means, The Gypsum Construction Handbook, 6th Ed., [purchase at Amazon] J. Wiley, (2009), ISBN 978-0-87629-258-7, quoting J. Wiley & Sons:
    One of the construction industry's longest-running, most relied-on references, The Gypsum Construction Handbook was first published by the U.S. Gypsum Company in 1904. For more than a century and through several editions, the book has become a trusted standard. This new 6th edition is an illustrated, comprehensive, and authoritative guide on all facets of gypsum construction.You'll find the newest product developments, installation methods, fire- and sound-rated construction information, illustrated framing-to-finish application instructions, estimating and planning information, and more. System descriptions – together with full data on products, accessories, tools, equipment, and applications – help plan and estimate projects and ensure compliance with performance criteria.Cost- and time-saving techniques keep the work on budget. New in the sixth edition are chapters on sustainable construction methods and products, building movement, fire resistance, heat transfer, sound transmission, and vapor/moisture control.The Handbook covers both new construction and repair and remodeling and includes: framing drywall and veneer plaster joint treatment and plaster finishing interior cement board ceilings conventional plaster
  • [16b] Gypsum Construction Handbook [purchase at Amazon.com] H17, Technical Folder SA920 and PM2, PM3 and PM4, United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124,
  • [17] Lath & Plaster Systems [copy on file as /interiors/LathPlaster_Nat_Gypsum.pdf ] - , 092300/NGC, National Gypsum Lath and Plaster Systems, National Gypsum Corporation, 800-628-4662 describing National Gypsum's Kal-Kore brand plaster base
  • [18] Metal Lath Specifications, Specification for metal lath and accessories, Lath and Plaster [copy on file as/interiors/Amico_lath-inside.pdf ] - from Amico, a lath and plaster accessory producer.
  • [19] Plastering, PM 5, Product & Systems Technology, US Gypsum, May 1998, web search 10.5.2010, original source: http://www.usg.com/rc/technical-articles/plaster/ [copy on file as/interiors/Plastering_USG.pdf ] -
    plastering-technical-guide-veneer-plaster-joint-reinforcement-systems-en-PM5.pdf
    United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124,
    Paraphrasing from this document: USG uses the term shadowing in this document in describing the visual effect over gypsum board joints caused by the lower moisture absorption rate (take-up) and lower capacity than gypsum base face paper. Shadowing at joints occurs where veneer plaster is applied over tape joints, requiring a second coat to completely hide the tape, providing a visually uniform surface. USG Advises: 'This [second] cover coat must be allowed to harden and dry before plaster application is started.
  • [20] Plastering Skills, F. Van Den Branden, Thomas L. Hartsell, Amer Technical Pub (July 1, 1985), ISBN-10: 0826906575, ISBN-13: 978-0826906571 [purchase at Amazon.com]
  • [21] Drywall Finishing Council www.dwfc.org, Members: CertainTeed Gypsum • Freeman Products • Georgia Pacific Gypsum LLC • LaFarge North America • Magnum Products • National Gypsum Company • Panel Rey SA • Rapid Set Cement • Saint-Gobain, Inc • Sherwin-Williams Company • Solid Products, Inc. • Southern Wall Products • Trim-Tex, Inc. • United States Gypsum Company • Westpac Materials
    • 'Joint Compound Drying Time, the Impact of Environmental Conditions', Drywall Finishing Council, Retrieved 8/16/12, original source: http://www.dwfc.org/wp-content/files/2010_03_16_Joint_Compound_Drying.pdf [copy on file as Joint_Compound_Dry_Tmie_DWC.pdf]
    • 'Jobsite Conditions for Applying Interior Finishing Materials', Drywall Finishing Council, Retrieved 8/16/12, original source: http://www.dwfc.org/wp-content/files/2011_09_16_Interior_Job_Condition_Specifications.pdf [copy on file as Drywall_Finish_Conditions_DWC.pdf ]
    • DWFC. Interior Job Condition Specifications For The Application of Drywall Joint Compounds,
      Drywall Textures, and Paint/Coatings'. Drywall Finishing Council, Incorporated. www.dwfc.org
    • DWFC. Recommended Specification for Preparations of Gypsum Board Surfaces Prior To Texture
      Application, Drywall Finishing Council, Incorporated. www.dwfc.org
    • GA. GA-214, Recommended Levels of Gypsum Board Finish. Gypsum Association, 6525 Belcrest
      Road - Suite 480. Hyattsville, MD 20782 www.gypsum.org
    • National Gypsum Company. ProForm Brand Drywall Finishing Products Construction Guide,
      National Gypsum Company, 2001 Rexford Road, Charlotte, NC, 28211, www.nationalgypsum.com
  • [22] The Gypsum Association www.gypsum.org Gypsum Construction Handbook H-17 [purchase at Amazon.com] . USG Corporation, 550 West Adams Street, Chicago, IL, 60661, www.usg.com
  • [23] Painting and Decorating Contractors of America www.pdca.org Smartwood/Rainforest Alliance www.smartwood.org
  • [24] 'Joint Compounds', United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124, retrieved 8/16/12, original source: http://www.usg.com/interiors/joint-compounds.html [copy on file as Mud_Types_USG.pdf]
  • [25] Gypsum Construction Guide, National Gypsum Corporation
  • [26]
  • [27] Lath & Plaster Systems, 092300/NGC, National Gypsum Lath and Plaster Systems, National Gypsum Corporation, 800-628-4662 describing National Gypsum's Kal-Kore brand plaster base
  • [28] Metal Lath Specifications, Specification for metal lath and accessories, Lath and Plaster from Amico, a lath and plaster accessory producer.
  • [29] Plastering Skills, F. Van Den Branden, Thomas L. Hartsell, Amer Technical Pub (July 1, 1985), ISBN-10: 0826906575, ISBN-13: 978-0826906571 [purchase at Amazon.com]
  • [30] Plastering, PM 5, Product & Systems Technology, US Gypsum, May 1998, web search 10.5.2010, original source: http://www.usg.com/rc/technical-articles/plaster/
    plastering-technical-guide-veneer-plaster-joint-reinforcement-systems-en-PM5.pdf
    United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124,
    Paraphrasing from this document: USG uses the term shadowing in this document in describing the visual effect over gypsum board joints caused by the lower moisture absorption rate (take-up) and lower capacity than gypsum base face paper. Shadowing at joints occurs where veneer plaster is applied over tape joints, requiring a second coat to completely hide the tape, providing a visually uniform surface. USG Advises: 'This [second] cover coat must be allowed to harden and dry before plaster application is started.
  • ..

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

  • Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
  • Gypsum Construction Handbook [purchase at Amazon.com] H17, Technical Folder SA920 and PM2, PM3 and PM4, United States Gypsum Company, 125 South Franklin ST., PO Box 806278, Chicago, IL 60680-4124,
  • ..
  • Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
    • The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
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  • The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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    Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd
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Hairline Crack Where Ceiling Meets Wall

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