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Structural Movement

When you see tell-tale signs of your wall separating from the ceiling, or cracks forming on your drywall tape and ceiling drywall, it can conjure fears of structural damage in your home. However, not all cracks in your drywall are a red flag for structural concern.

This article highlights what might cause cracks on your walls and ceilings besides structural issues, steps you can take to prevent your wall from separating from the ceiling, and how to repair and conceal the cracks.

Types Of Cracks That Form On Walls And Ceilings

Many factors ranging from weather, structural issues, wear and tear, exert stress on building frames may cause gaps of different sizes, lengths, and depths on different parts of the ceilings and walls.

Which cracks form on walls?

Cracks that form on walls fall into the following three categories:

  • Cracks on the interior walls, such as in the plasterboard
  • Cracks on the exterior walls, such as in the brickwork
  • Cracks on the foundation walls

Which cracks form on ceilings?

Cracks that form on the ceiling include:

  • Small cracks are known as spiderweb cracks on plaster or paint. These are usually not a problem
  • Long cracks running across the ceiling continuously down the walls. Such long cracks running down the walls from the ceiling signify structural damage
  • Cracks that are accompanied by sagging of the ceiling. Indeed, this is not a good sign

When these cracks form where the ceiling and the wall meet, the wall separates from the ceiling, leaving a gap.

When Cracks Form On Walls And Ceilings

Yes, wall and ceiling cracks can signify serious structural damage. For example, large deep cracks can indicate structural problems that require the intervention of a structural professional. While they can be a red flag for structural issues, cracks that form on walls and ceilings may not always be something to worry about.

For example, ceiling cracks accompanied by sagging will likely result from structural damage. In contrast, gaps that form where the walls meet the ceilings may not necessarily imply structural damage to the ceilings or walls. Whether you will need to take the cracks seriously when they appear will depend on:

  • What caused the crack
  • Whether the identified cause is ongoing or likely to recur
  • Location of the crack
  • The shape of the crack, whether it is jagged, horizontal, or vertical
  • Whether there is any kind of separation: the wall separating from the ceiling or construction material separating from the building frame

The typical rule of the thumb is never to ignore your instincts. Contact building inspection professionals right away when you suspect the cracks on your ceilings and walls are a structural concern.

What Causes Gaps Between Walls And Ceilings?

Cracks forming in your drywall between the top of the wall and the ceiling may contribute to drywall separating from the ceiling.

The likely causes of cracks on walls and ceilings include the following:

  • Truss uplifting
  • Vibrations
  • Improper drywall finishing
  • Foundation settling

Truss uplifting

A typical roof truss consists of bottom chords, which form the horizontal ceiling joists, and the top chords, acting as the diagonal roof support. The space between the bottom and top chords is called the attic. Most homeowners spread some material on the bottom chords of the trusses to keep them dry as condensing moisture soaks into the top chords.

As the condensing moisture soaks into the top chords, they expand, and the truss moves upwards, a phenomenon known as truss uplifting. If the truss had been nailed to the wall plates, the expansion at the joints between top and bottom chords combined with the stress from the nailing could lead to your wall separating from the ceiling and also cause cracks on your walls and ceilings.

Vibrations

Vibrations of sufficient strength, mainly from construction activities around your home, can cause your drywall to crack. Such construction activities include:

  • Use of heavy machinery for compaction of soil
  • Use of explosives for exaction and blasting

It is advisable to assess cracks resulting from construction activities in your area and then seek legal advice. Although not common in Australia, earth tremors and earthquakes can also cause cracking of walls and ceilings.

Improper drywall finishing

Cracks will form on drywall joints that are not properly taped. Drywall taping is an integral part of drywall finishing, which, if not done correctly, can cause cracking in ceiling drywall and drywall tape separation from the ceiling.

When you see your ceiling drywall cracking or the drywall tape separating from the ceiling, it may signify poor workmanship, such as using an inadequate amount of drywall mud during the application of the drywall tape.

Foundation settling

All building foundations settle to some extent after the construction is completed. The settling can be normal or extreme, with varying pressure levels on the building frame leading to cracks. For example, a shift in the foundation can be caused by drywall tape separating where the ceiling and walls meet. However, gaps between your wall and ceiling are nothing to worry about if they are due to normal foundation settling.

How To Prevent Truss Uplift

Wall and ceiling cracks caused by truss uplift and other structural movements that happen after a house construction can be prevented or concealed using the following methods:

  • Attach trusses on the wall plates using L-shaped truss clips
  • Remove wall and ceiling fasteners
  • Install crown moulding

Attach trusses on the wall plates

Trusses and walls should be able to move independently during the structural movements and adjustments that follow a house construction to prevent the wall from separating from the ceiling. This is, however, not possible if trusses are nailed on the wall plates during the framing of the roof.

The nailing causes some constrain when the truss moves due to expansion and structural adjustments in the ceiling joist; hence your wall separates from the ceiling. Attaching the trusses on the wall plates with L-shaped truss clips instead of nailing them directly will allow the trusses and the walls to move independently.

This is because the clips have nail slots that will enable them to slide up and down as the truss moves. It is never too late to install these clips, even after your walls and ceiling have been drywalled. Simply remove the nails holding the trusses to the wall plates and use L-shaped truss clips with special slots. Drive the nail into these clip slots leaving the head out by about 0.6 cm.

Remove wall and ceiling fasteners

It is possible to prevent the cracking caused by truss uplift by removing the ceiling fasteners (within 40.5 cm of the corners) and wall fasteners (within 20.3 cm of the corners). When your drywall is fastened using nails, pound the nail heads through the drywall.

If screws are used as the drywall fastener, remove them using an appropriate tool. Doing this helps to prevent the wall and ceiling drywall from moving as the truss moves. Fill with joint compound and repaint to conceal the holes left on your drywall after removing the fasteners.

Install crown moulding

Another way to prevent truss uplift and hide wall and ceiling cracks is to install crown moulding and nail it only to the ceiling. It is typically advised that you do this during the cold of winter when the expansion of the roof truss is at maximum.

When Should Wall And Ceiling Cracks Worry Me?

Rule number one is never to ignore your instincts when you suspect the cracks on your walls and ceilings result from structural issues in your building. Contact a building inspection professional right away for a comprehensive inspection report.

The following are some of the tell-tale signs that an underlying structural issue has caused the cracks on your walls and ceiling.

  • Several small cracks on your walls and ceiling
  • When your walls are no longer in contact with the ceiling
  • Long cracks running across the ceiling continuously down the walls
  • Cracks that are accompanied by sagging of the ceiling
  • When doors and windows begin to stick
  • Bowed walls

Repairing And Sealing Drywall Cracks

There are many options for repairing drywall cracks depending on the size of the gap. The nature of the cracks will also determine the repair cost.

Very thin cracks on the walls and ceiling can simply be sealed with filler and paint, while installing crown moulding may help to conceal the gaps between walls and ceiling.

To determine the appropriate repair method that will help to restore your walls and ceiling, you will need an expert assessment of the underlying cause of the cracks. In extreme instances, repairing cracked walls and ceilings may involve demolition and reconstruction.

Cost Of Repairing Drywall Cracks

The cost of repairing cracks on your drywall will depend on many factors, including the nature of the underlying cause. Repairing cracks caused by truss uplifting is cheaper than those caused by underlying structural problems. You should do repairs as soon as you notice the cracks, as the cost can be higher if you ignore them.

When To Call Professionals For Structural Issues

More often than not, cracks in ceilings and drywall joints are due to truss uplift. Sometimes, these cracks form between the walls and ceilings, creating gaps that cause the wall to separate from the ceiling. Fortunately, ceiling and wall cracks due to truss uplift can be prevented during the framing of the roof truss and even after your walls and ceiling are drywalled.

While ceiling and wall cracks are largely due to truss uplift, never assume that sometimes the cracks can indicate an underlying structural problem in your building. Contact building inspection professionals within your locality if you begin to see cracks whose causes you are not sure about.

Getting a building inspection report will provide insights on the severity and likely cause of the cracks in your walls and ceilings. If you are in Adelaide, Australia, you can contact reliable inspection companies for an inspection.