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Open drywall nail pop © Daniel FriedmanDrywall Cracks
Cause & prevention of cracks or ridging in plasterboard or gypsum board ceilings & walls

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.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

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

Drywall ceiling crack locations © Daniel Friedman

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

Gypsum Board Installation Error contribution to gypsum board cracks & damage

E-Z Strip (C) drywall Expansion Joint Strip Installation Detail - adapted (C) InspectApedia.com

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.

Long drywall ceiling without control joints cracked © Daniel Friedman

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.

Long drywall ceiling without control joints cracked © Daniel Friedman

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 / DRYWALL 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.

Drywall corner cracks due to frost heaving © Daniel Friedman

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.

Below 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.

Drywall corner cracks due to frost heaving © Daniel Friedman

See FOUNDATION CRACKS & DAMAGE GUIDE

To repair this drywall crack and to reduce the chances of its reappearance, we

Common types of drywall joint tape include paper tape, fiberglass mesh self-adhesive, and reinforced extra-strength fibre-based self-adhesive drywall joint or crack repair tape (C) Daniel Friedman at Inspectapedia.com ... Drywall corner trowel Marshalltown No 23 used with mesh tape to repair a corner (C) Daniel Friedman at InspectApedia.com

 

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.

Ceiling drywall crack at natural stress point following framing shrinkage in new construction © Daniel Friedman ... Ceiling drywall crack at natural stress point following framing shrinkage in new construction © Daniel Friedman

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.

Drywall installatin, ceiling (C) D Friedman Eric Galow

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].

Drywall crack at wall/ceiling stress point (C) Daniel Friedfman... Drywall crack at wall/ceiling stress point (C) Daniel Friedfman

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.

Drywall crack at doorway opening - building settlement (C) InspectApedia.com ... Ceiling framing with trusses - drywall installation question (C) InspectApedia JW

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 / DRYWALL 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.

Sinking house built over stream bed, New York © Daniel Friedman ... Sinking house built over stream bed, New York © Daniel Friedman

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.

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.

Sinking house drywall cracking, also bad tape (C) InspectApedia.com

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]

Sinking house drywall cracking, also bad tape (C) InspectApedia.com

In our second drywall 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:

Northridge Earthquake 1994 exterior wall damage © Daniel Friedman

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 / DRYWALL 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

Drywall crack at intersection typical of ceiling wall separation from arching roof truss © Daniel Friedman

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 ridging © Daniel Friedman

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:

Drywall Crack, Movement, Failure Research

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-04-04 by Inspectapedia Com Moderator - basic drywall crack or earthquake cause?

@Anonymous,

Haha. Actually if you're referring to earthquake cracks in drywall, see the page top photo.

On 2022-04-04 by Anonymous

I think it can be a Earth quack

On 2022-03-10 by Inspectapedia Com Moderator

@Dan,

Then I would still suspect it is a common drywall crack occurring as the result of minor wood framing shrinkage and movement.

So it's a cosmetic concern; you can use mesh tape and joint compound to repair the crack, re-paint, and if we're both lucky you won't see further damage in that location from that cause.

On 2022-03-10 by Dan

@Inspectapedia Com Moderator, Hello. Thanks for looking at this. It is wood framing with sheetrock. I don't see anything else like it in the house and no cracks in visible foundation.

On 2022-03-09 by Inspectapedia Com Moderator

@Dan,

What's the construction of the wall? Wood framing? Solid masonry?

Are there any other signs of building movement such as settling, sagging, bending, bowing, bulging walls or foundations?

If no, then this may be a common drywall crack occurring as the result of minor wood framing shrinkage and movement around a wood-framed window opening.

On 2022-03-09 by Dan

Hello,
Drywall crack at entryway from one room to another. Been this way for about 2-3 years. Very slow in growing if at all. .04" at bottom. Any thoughts? Sheetrock bows in from other side at top and has been that way all along. Thanks!


On 2022-01-20 by Inspectapedia Com Moderator - fieldstone foundation home has drywall crack

@Jamie,

I can't see much but that looks like a hairline drywall crack at a seam and at a natural stress point in the building framing. I'd patch the crack with high-strength mesh tape and joint compound before re-painting. If the crack recurs or becomes wider that might merit further investigation.

On 2022-01-20 by Jamie

Here is a photo of the entire wall & I circled to where the crack is that you see in the first photo I uploaded.

For reference, our home is located in Iowa & was originally built in the 1900's (fieldstone foundation for the portion built in around 1930's, then a second fieldstone foundation for the addition built in 1960's & then in 2000's there was a garage added on which has cement foundation.)

In this photo the door to the left is going to the garage (Idk if the switch from fieldstone to stone foundation to cement would play a part or if the vaulted ceilings need something more?) It's hard to really gauge it based on things being level because it's a farm house & has never been "perfect"

1900s fieldstone foundation house with drywall cracks (C) InspsectApedia.com Jamie

On 2022-01-20 by Jamie

While painting I noticed a drywall crack that nearly extends from the corner of my wall to the ceiling. I tried to make it easier to see in the photo, but aside from the usual drywall crack fears (fieldstone foundation home), I'm unsure if it's more concerning because the line isn't clean cut straight up & down?

On 2021-07-31 by inspectapedia.com.moderator - drywall cracks only visible in winter

@ Rose

You shouldn't need to hire an engineer or even an experienced home inspector, though the latter, if a good one, could do the job; First, I'd expect an experienced drywall contractor to recognize the crack complaint and diagnose its cause;

I'd like to offer more specifics myself but I just can't see a thing in your photos.

The location of the crack, its relation to structural components and those materials and how they might move, and a confirmation that the movement is cyclical and only related to temperature changes are some of the important steps.

If you like, look at the page top EXPERTS directory, find a home inspector in your area, give her or him a call, discuss your concern, and ask if that falls within the inspector's expertise. Home inspectors vary widely from generalists who follow a checklist to people very experienced in construction methods, troubleshooting, diagnosis, repair.

On 2021-07-31 by Rose

@inspectapedia.com.moderator, the remodel was done several years ago. The room was completely gutted down to the studs. We had the ceiling made higher. We had them put in a 9 foot ceiling.

We installed windows and doors to the room. Most of the room are windows and patio door. Before the remodel we never had cracks in the drywall. After the remodel cracks appeared in the winter.

We live in the Cleveland , Ohio area and our winters are very cold. The room has heating and air conditioning and a dehumidifier. What type of inspector should I hire to determine the problem.

On 2021-07-11 by inspectapedia.com.moderator

@Rose,

Before proposing a "fix" to the -currently invisible- drywall cracking we need to diagnose the cause - so as to choose the right and effective repair of what sounds like a recurrent cosmetic issue.

Understanding how your building is constructed, and some contextual information about these building cracks: building construction type, materials, age, country, city of location, climate, soil conditions, and variation range of temperature and humidity are examples of data you and your onsite inspector will need to consider.

Common causes of cold weather drywall cracking include

- thermal movement of different building materials - see THERMAL EXPANSION of MATERIALS

and at the bottom of that page an index to key thermal movement articles

- rising roof trusses - affected by changes in both temperature and moisture level - see TRUSS UPLIFT, ROOF

- more-serious: foundation settlement or frost heaving - See FROST HEAVES, FOUNDATION, SLAB

Using the on-page box to Search InspectApedia for "thermal movement of materials" will find a broad range of examples of this sort of movement that can produce cracks in building materials

On 2021-07-11 by Rose

@inspectapedia.com.moderator, the reason you can’t see the crack is closes up in the summer. The cracks reappear in winter. They start at the corner of the soffit to the top of the window exact same patter on both sides of the room. Taping didn’t stop it from reoccurring.

On 2021-06-23 by inspectapedia.com.moderator

@Rose,

Sorry but I actually can't see the cracks of your photo.

If they are 1/8" or less in width, occurring at and following a right angle joint such as soffit to wall or soffit to ceiling, it's probably the case that you need a better taping job there.

On 2021-06-23 by Rose

We had a room completely gutted and remodeled. We had the ceiling vaulted. There is no attic above the room . It was an addition. It has a slab foundation. A soffit was added to install canister lights.

Since then we have cracks that appear from the corner of the soffit to the corner of the window. Identical crack on both sides of the room. The cracks only appear in the winter. What is it and how can it be corrected?

...

On 2021-02-23 by (mod) - it's "gypsym" wallboard, not "Egyptian" wallboard.

@Kathy M,

I meant "gypsum" wallboard as discussed in this article series.

Internet down, I was trying to reply using a cellphone and my phone is convinced it knows-better what I should be saying. (Nothing against Egyptians.)

On 2021-02-21 by Kathy M

Thanks Dan. I am not sure what Egyptian Board base is but will Google. Had a fire in 2015 in another part of the house and wondered if there may have been moisture in walls from where they hosed the house. or movement where we had to have some of the roof rebuilt. Also added 4 piers about 4 years ago so may have movement from that.I think I will get a home inspector to come look.

On 2021-02-04 - by (mod) -

Flaking peeling coating on drywall surface (C) InspectApedia.com KathyMy most complete advice that is more thorough than trying to make up an answer a new off the cuff is in the article above and others in this series so I hope that you will take a look.

I do notice however that in your photo we've lost what looks like a skim coat on an gypsum board base.

Or possibly we are seeing the separation and peeling of painted-ove wallpaper that is no longer well-adhered to the gypsum board surface.

So it could be that the skim coating was not properly applied such as applying it over dust or dirt, or it could be that there's been a leak or moisture problem. Those are some things to look for.

Typically I find and remove all of the loose material on the wall by feeling for bubbles or bulges, cutting around the damage with a drywall knife, removing the loose material, skim-coating with joint compound to fill the damaged areas, sanding smooth, priming, and painting.

Watch out: working on old homes with painted-over wallpaper I've sometimes found that it's hard to stop removing loose surface material; particularly when we wet the edges of the removed area by the application of joint compound, more painted-wallpaper loosens its grip on the wall surface below.

If that problem is sufficiently widespread it's less costly and faster to laminate a new layer of 1/4" drywall over the whole wall than to keep fiddling with patching, taping, etc.

On 2021-01-31 by Kathy M

65 yr old house previously remodeled in 70's & 80's. Cracking/peeling walls,bubbles and nail pops. Cause? How to repair?

[Photo above]

On 2020-10-13 - by (mod) -

Steve

Thanks so much for the comment: hearing from pros in the field is particularly helpful to everyone.

Before prescribing a repair or preventive measures for the ceiling-wall crack, if we can diagnose the cause with confidence we'll be more certain of the repair.

It's possible that you are seeing the infamous "rising roof truss" crack that occurs at an interior partition wall/ceiling juncture. In particular this crack shows up between ceiling and wall of a wall that is close to the middle of a building and runs parallel to the front and rear walls or roof eaves, AND where the roof is supported by trusses.

That problem occurs because of differences in arching of the truss upper and lower components that in turn are because the truss bottom chord that supports the drywall ceiling is buried in insulation.

The "fix" is to eliminate the screws or nails securing the drywall to the ceiling for a couple of feet on either side of that interior partition wall. In bad cases where the drywall is sufficiently damaged as to justify demolition and re-work, there are special clips that are used to hold the drywall to the wall top instead of the truss bottoms near the building center.

None of that repair needs to be done from that cramped attic;
Where I've fixed these cracks I either removed ceiling drywall screws that were into the truss bottom chord for a couple of feet on either side of the center partition wall or if nails were used, I use a punch to drive the nails all the way into the truss bottom, then patch the hole left in the ceiling and re-paint.

A second cause of cracking in the ceiling drywall may come from people or heavy storage over the area of damage - in particular when the ceiling is framed with minimal sized lumber; I've found this in cottages built in North America, the UK and Spain that date from the 1940s and 50s. But those areas of damage are different: the damage occurs closer to the center of the span, not right over the middle partition wall.

As it will help others and might encourage some useful comment, I will RE-POST this discussion over at

TRUSS UPLIFT, ROOF

And I'll be grateful if you can post a photo or if you have further comments, criticism, or suggestions.

On 2020-10-13 by Steve

As a drywaller i see a lot of cracks on ceilings. That begin at a outside corner interior wall. And extend across most of the room's ceiling. I figure the cause is movement in ceiling rafters. Where one is extended across the entire distance of the exterior walls and the one next to it is supported by interior upper wall plates . the crack starts at these supported locations and extend across the distance of all the unsupported joists. Because stiffeners were not put in place to keep bowing from occurring
How can this problem be best corrected with minimal attic space to work in.

On 2020-05-13 by (mod) - common causes/cures for drywall cracks at a window

Drywal cracks at cantilever and window (C) InspectApedia.com Sherman BBrad

Thanks for an interesting and helpful question that I'd phrase as: Interior details to permit and cover drywall crack from cyclic building movement.

Given the location of the crack and the surrounding framing deign, I don't assume this drywall cracking and wall movement are due to foundation settlement nor expansive soils etc.

First: in my experience cracking at a location like the one shown in your photo - where there is an intersecting roof plane that can be difficult to tie to the main structure, and where there is a framed opening for a window (where header connections are critical) it's not a surprise to find evidence of movement.

The underlying problem could be inadequate header at the window, inadequate connections of the lower sloped-roof to the main structure, or a similar problem.

Second: expansive clay soils can damage more than drywall, also moving and damaging foundations and in extreme cases, plumbing connections. So it is worth investigating whether a soil watering or de-watering system, such as commonly used under buildings with expensive clay soils, is necessary and would be helpful.

Third : In the location shown in your photo, it would be easy to add wooden trim that is fastened only on one side of the moving wall. That would cover the crack and allow movement without any visual evidence in the room. You'll need to extend the trim and include it in the interior design for it to make sense. f

Watch out: Before pretending to repair the window cracks I'd want to be confident that there is no other movement in the structure that needs repair and that might indicate more serious need for improved structural connections of roof or window header.

If you are confident that there is no significant underlying structural concern, then a cosmetic approach is fine.

For areas of less total movement I've used reinforced mesh tape before taping over and repairing crack damage.

In some locations indoors, such as at a wall-ceiling juncture, we use clips to carry the drywall so that the building can move without telegraphing that movement into drywall cracks. Those clips are described in our article that discusses cracks caused by rising roof trusses. See

details at TRUSS UPLIFT, ROOF

Thanks for asking - let me know what questions or thoughts occur to you on this.

On 2020-05-13 by Brad Sherman

[Regarding the photo shown above]

Differential building settlement, a change in building materials (standard timber frame / brick pier for original house and thermacell polystyrene / concrete for new work on big concrete footings), and stress concentration at the window corner have contributed to this crack.

At one stage it opened and I filled the gap and repainted. It subsequently contracted and squeezed out my earlier repair. Now it’s opened up again. I would just like to straighten the lines and make things look more ‘planned’ because the clay soils here mean the expansion/contraction cycle will continue.

Can you advise what sort of approach is best suited to lessen the visual impact of inevitable future building movement?

On 2020-02-03 - by (mod) -

Susan

You ask a perfectly reasonable question but from just your text I don't know what's going on.

I use the "fear-o-meter" approach to decide how to act on questions like this.

What else can we find that raises or lowers our level of concern?
At what point do we cross an action threshold: or when do we cross the line between: keep an eye on it - and cut an opening or do other invasive inspection?

If there's no water entry, no mold, no smells, no signs of structural movement, you might wait to act.

To know for certain what's happening you'd need to remove the drywall (as less troublesome than digging up the foundation, a step that can cause its own problems).

Outside, keep roof runoff and surface runoff away from the foundation.

Search InspectApedia.com for FOUNDATION CRACK DAMAGE to see more detail.

On 2020-02-01 by Susan Swan

I have an almost 50 year old back split home, with the lower level is about 50% underground. The bottom of the windows in the downstairs at right at ground level. I just discovered a horizontal crack about 1/2 an inch under the window running the length of the window. The windows are probably 25 years old. Should I be worried that it is the foundation? The wall doesn't have any water stains and it doesn't smell mildewy in the area.

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.


...

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