The Hidden Danger of Transitional Ceilings
Few contractors, home inspectors or engineers are aware of the danger that certain plaster ceiling systems pose. Though many ceilings will collapse after a pipe bursts or a roof leaks and soaks the ceiling or because of an impact, etc. this type of collapse can occur without other contributing causes.
Because of inadequate attachment systems, these plaster ceiling systems can collapse unexpectedly, causing a huge mess, property damage, injury......even loss of life.
If you have a specific question relating to the safety or soundness
of your plaster ceiling,and do not find the answer here,
please contact us in the form below.
Transitional Ceilings: What are they?
both residential and commercial buildings
I have coined the term 'Transitional Ceilings' to describe the types of plaster ceiling systems that were installed roughly between 1920 and 1960.
The term 'Transitional Ceiling' refers to the period of transition between the ceiling system of 'traditional' plaster-over-wood lath to modern drywall. This system usually consisted of a plaster base-coat and top-coat, applied over a monolithic drywall-like lath or base, but metal lath attached with nails has also been known to fail spectaularly*
Three Common Plaster Ceiling Systems
Plaster over Wood Lath: Pre- 1920's
The method used up until the 1920's, plaster over wood lath, goes back several thousand years in one form or another: wood strips were nailed to the joists and studs, upon which was applied a base-coat plaster which formed 'keys' as the material oozed between the wood lath and hardened. Over this was applied the scratch and brown coats and finally the top-coat of smooth, white plaster.
(This type of plaster can also collapse, but typically in smaller segments. Usually it is preceeded by obvious bulging plaster before it gives way. Part of the ceiling in the Emily Dickinson homestead recently collapsed)
Plaster over Gypsum/Metal Lath: 1920-1960
When gypsum lath was invented in the 1920's, it was a great labor-saver. Instead of nailing thousands of wood strips to the joists, large sections of gypsum lath could be attached quickly by means of nails, clips or wire to the joists. Three coats of plaster were then layered over the monolithic lath. Metal lath was also used and attached by the same methods (See video on Sunshine Elemetary School and slideshow of Hartford Mansion below)
Modern Drywall : 1960 - Present
Over time, somewhere in the 1960's, the base/scratch/brown/top-coats were eliminated, and only the joints were taped and mudded, giving us our modern drywall system.
General Questions
If you came her with a question you cannot find the answer to, feel free to contact us here.
I went in to check on the guys and hear a snap, crackle, pop sound. What was that? ....
Then we heard and saw more cracking and stood back.
BOOM!!!! The ceiling came down.
I took this picture shortly after it happened.
The Test of Time
Unfortunately, the methods for installing 'transitional' ceilings have not always withstood the test of time. Many are undersupported and a number have collapsed unexpectedly, causing property damage and sometimes injury or loss of life.
The Weakest Link: What Went Wrong?
Though they were installed according to the best knowledge available, time has proven that many of these 'transitional' ceiling systems were undersupported.
They simply did not have enough holding power to support the weight of all the plaster.
The weakest link is usually where the gypsum base is attached to the ceiling joists. Often it was attached with nails, clips or wires.
Nails
In the case of nails, they were simply common nails without any special treatment that would have given them the extra holding power they needed. With thousands of pounds of weight constantly pulling downward, they eventually can loose their gripping power and slip out of the joist.
Clips
Made from thin gauge steel, these attached to the perimeter of the rock lath and were nailed to the joist. The clips tend to bend and release the lath over time.
Wires
Wrapped around a nail which is attached to the side of a ceiling joist, the wire holds onto the gypsum lath by various means. In this case, the wire appears to be either unravelling or stretching under the weight.
With each of these attachement methods, there is a danger of collapse, if the problem is not properly diagnosed and remedied.
Here are a few instances of this kind of ceiling collapse:
"Jane Wald, the museum's executive director, said the ceiling's collapse was largely the result of nails that were too small and spaced too far apart. She noted that the plaster was not original to the homestead, but dated to renovations undertaken at the house when it was a private residence in the early 20th century."
(Though this man believes his radiant heat had something to do with this collapse, the real cause is the inadequate attachment system. Expansion and contraction would not have affected the attachment system had it been adequate to begin with.)
And three more stories.....
Transitional Ceiling Collapses: Contributing Causes
Transitional ceilings also collapse due to contributing causes, whether from a plumbing or roof leak, the addition of other materials onto the surface of the ceiling (drywall, acoustic tile, etc) or excessive vibration caused by remodeling or nearby demolition/constructon.
Because they are already already are undersupported, any of these factors can hasten collapse. Proper remediation prior to collapse may prevent collapse in spite of contributing causes.
(Note that other ceilings began to fall that had not been doused with water. Likely caused by general vibration caused by demolition)
'In fact, in WA alone, the RAC deals with about two hundred ceiling collapses a year, none of them covered ... and that's just one insurance company, in one state. Delia says "had the RAC told me this was a daily occurrence I would have done something about it" John says "it is well known in the building industry" maybe so, but how many families are aware of it ... especially those who pay home insurance for something they assume will be covered? Kim's says "of course they should let home owners know definitely"'
A Definition of Structural System Failure
If, at any point, the ceiling begins to detach from the structure, as evidenced by certain cracks or gaps between gypsum lath and ceiling joists, it has already begun its descent to possible collapse and thought it may not have collapsed yet, it has for all intents and purposes, failed.
It may never collapse in fact, but it has lost its structural integrity and could pose a danger to the occupants of the home. The best course of action is to address it now, before it collpses.
The Good News?
With proper diagnosis and remediation,
potential damage and disaster can be prevented.
More good News:
Your Homeowner's Insurance May Pay for This Repair!
When I say repair, I don't mean AFTER it has fallen!
If your ceiling shows some evidence of impending collapse (specifically straight-line cracks), call us to properly diagnose the condition. If your ceiling is an undersupported, we will work with your insurance company on your behalf to help get it paid for!
" Philip took his time to explain in detail why the prior repair
did not work....[he] explained the need for anchoring the
weak attachment of my ceiling plaster system to the ceiling joists,
before patching the crack.
Philip's attention [to] detail was instrumental in getting
the repair paid for by my insurance company,
less my deductible."
Mary Ann Settle
Reidsville, NC
More
Points to Ponder
The first thing one considers is the age of the home.
If it was built between 1920 and the early 1960's and
has a plaster finish, it is a likely candidate for having a
transtitional ceiling.
collapse?
You don't. Though there are clear signs of ceiling system
failure, no one can predict the inevitability of collapse or the time of collapse.
Based on eyewitness account, transtitional ceilings could
collapse whether there are signs or not.
Some ceilings show clear signs of failure and sagging. Without remediation,
and depending on the extent of the failure, collapse may be inevitable.
The clear and classical sign of plaster ceiling system failure is the classic straight-line
crack down the middle of the largest room.
Occasionally there may be several straight-line cracks. This correlates to the meeting of the joints of
the gypsum or rock lath. At other times the lines may zig-zag perpindicularly to each other, again
following the joints of the gypsum lath.
Rarely, the cracks may follow a circular or flowing pattern.
All of these cracks are indications, not of settling or normal stress, but of ceiling attachment failure.
How close a particular ceiling is to collapsing is impossible to determine.
One way is determine the extent of failure is to look at the back of the ceiling from the attic,
underneath the insulation. From here you can see how far, if at all, the ceiling has crept away from the
ceiling joists.
I have also spoken with homeowners who told me there were no
visible signs (that they noticed) before complete collapse.
Unfortunately few plaster or drywall repair people understand what they are
looking at and don't apply the correct solution.
They may mesh-tape and patch these ceilings, but the cracks will
come back because they did not understand and address the
underlying cause. Good money is wasted on an ineffectual
repair....
Fortunately, it is possible to fix these ceilings
for long-lasting safety and beauty!
at 336-327-5523 for a free telephone consultation.
Estate Plaster Inc. has answers.
Tearing out a monolithic plaster ceiling is very intrusive,
expensive and can be dangerous if done improperly. And in most
cases, it is completely unnecessary. Besides the dangers of
the whole ceiling falling out at once, causing further damage
or a risk to personal safety, there may be asbestos in your
attic insulation.
Estate Plaster, Inc. can address your failing plaster ceiling with minimal
intrusion and have in many cases been successful in helping to get
homeowners insurance to pay for these repairs...including the painting !
Let us work with you and your insurance company
to get this done for the safety of your family and belongings!
straight-line crack across the middle of the room.
What do I do now?
Estate Plaster, Inc. has experience with a number of techniques
for securing transitional ceilings so they no longer pose a danger.
We have addressed this condition in hundreds of homes in N.C.
After an on-site inspection, answer all your questions. and give you
an estimate, describing the specific process we will use in order
to secure your ceiling.
We clean up each day and use a dustless sanding system for your
maximum comfort.
Work with us and we may be able
to get your homeowner's insurance to pay for it!
for a free estimate !
Estate Plaster, Inc.
606 Scott Ave.
Greensboro, N.C. 27403
(336) 327-5523
Philip LaMachio, President
and legal citizens of the United States.
- We do not employ illegal labor to maximize our profits.