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Question DetailsAsked on 1/3/2014

I have a large crack, about 1/2" wide, running all the way across living room ceiling. Help?

I have a large crack, about 1/2" wide, running all the way across my living room ceiling. It starts on a fireplace wall and runs the entire span of the room. I also noticed some the the crown molding around the room is separating from the ceiling. The crack does not run through to other rooms. My living room is in the center of my house with a finished basement underneath it. The basement looks unaffected. What could cause this? The crack has been there for a while now and has not grown any larger. Any advice or help is appreciated.

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8 Answers


That is an AWFUL wide open crack for a ceiling - usually they will be just enough to put a pencil point in, and then if the ceiling keeps sagging, more parallel cracks will open up every few feet away oer the years, from center of room toward outside. A concentrated crack in one place like this is very odd - all I can guess is that it is at a drywall joint that was made continuous across the room (should have had sheets staggered), and your ceiling joists (upstairs floor or attic joists) are sagging, either due to overload or rot or undersizing.

One other possibility, related to above, is that you have a truss support system for your roof and an attic or roof is over your living room and your trusses are sagging due to waer damage or overload, causing a sway-backing in the center of your room - guessing here the crack is roughly across the center of the ceiling. If this is the case, the crack would be running perpendicular to the trusses. If the crack is parallel to the trusses, could be an indication that one truss has problems, with the crack forming right along and underneath it.

If rooms are above the living room, then overloading or water damage in the flooring (unlikely to be water, as enough to rot beams would almost certainly show as living room ceiling staining and drips), or if parallel to the overlying floor joists, cracking or other failure of one joist.

One other possibility which you can check by poking into the area a bit with a small sharp object like a finish nail, is if they left a gap in the drywall sheets 1/2" wide and just taped over it,and the tape is coming loose and revealing a pre-existing gap.

I presume there is no indication of the house having been added onto in the past, and that this is the joint between the original house and the addition. It is very common for additions to settle relative to the original part of the house, opening up tension cracks which are widest towards the top of the house and narrow down to zero or very small as you come down to ground level, and commonly pass through ceilings and down wall surfaces, and can even break or crimple siding and roofing.

Only other thing I can think of is if the basement (half basement) is under the living room only and the adjacent rooms on each side are slab on grade, perhaps they are settling relative to the main part of the house (especially if they were additions after initial construction, but slab on grade would always be expected to settle more than a full basement), so the ends of the house are settling relative to the center, and pulling the ceiling and roof apart slightly - sort of bending the house over backwards so to speak, and "breaking its back" a bit.

If this was a hairline ot 1/8" crack I would say spackle and paint it, and watch for reopening which would indicate continuing movement. For a 1/2" crack, unless a gap in the drywall sheets now exposed due to joint tape peeling or drywall compoound betweenthe sheet edges falling out, I think you need to get the ceiling joists and overlying structural features looked at - this might just be a fluke due to foundation settlement and poor construction practices, or it could be an indication of serious overloading or decay in the joists which should be remedied ASAP.

My recommendation - if there is an open attic over the living room, is to pull back any insulation and look at the joists ove the crack for rot, sagging, or cracking. If you see a problem, you need a general contractor very experienced in residential structural repairs, and if not due to water damage or obvious originally defective joists, first a structural engineer to figure out why they are failing. If not evident what the problem is or if you do not have visible access from above, you should probably get a structural engineer to look at it - he may have to open up small holes in the ceiling to look at the joists above with a fiber optic camera, if not open above in an attic,which will need to be repaired with spackle and paint at some time after any repairs are done. Probably about $200-400 depending on accessibility and whether you want a verbal consultation or a formal written report. - a structural remedial design would likely run another $250-1000 depending on nature of the problem - usually in the $500- range for this type of problem, if not related to a foundation failure, which I consider less likely here.

Hopefully Todd or Don will jump in with their opinion - this is one of those cases where the settlement might be mostly done by now and not open up more and could just be patched with drywall compoound or spackle and painted and watched - that would be the watch and see way, and if it started reopening then you would know you have an active situation on your hands that needs close looking into. Of course, on the other hand, it could be indicative of a serious problem that will get progressively worse, and cost a lot more to fix if it totally fails than it would now. You did not say how old your house is - if less than about 3 years, this is probably more likely to be due to initial foundation settlements than if the house is quite old and a large crack is openign up now. You also did not say if this is a new crack in the house, or if the house is new to you so you do not know how long the crack has been there - it may be, if you are fairly new to the house, that it has been there since the house was build or shortly after, and has not opened up since then. Tough call on what to do if you are not able to see the joists from above - personally, in that case I would take my fiber optic camera and start checking the joists for signs of damage, and if I saw nothing I would patch, paint, and watch to see if it opens up again more than a hairline crack.

Answered 6 years ago by LCD


Just about all LCD said could be the cause of your cracks. My first thought was extreme joist lift. If you could provide more info it might help us answer this question.

1 How old is your home

2 How many stories high is your home and is the attic directly above living room

3 Which way does the ridge (center of roof) run in relation to crack

4 How long has this crack been there

5 Does the crack change with the seasons

6 The separation you see in the crown moulding is it on all walls

7 Does the basement ceiling have drywall on it

And actually it should be number one is the ceiling drywall? I doubt that it is plaster but you never know, though your answer to number one would probably have answered this.


Answered 6 years ago by ContractorDon


Thanks so much for all of your input. Here are the answers to the questions you asked.

The house was built in 1972. It is a single story home with a half basement/half crawlspace. Attic is above living room. The ridge (center of roof) runs the same direction as the crack. I have owned the home since 2001. The crack appeared about a year ago and has not grown since. I have not noticed any change with the seasons. The crown molding seperation is along all the walls in the room but, more signifigant on one side of the crack than the other. The basement ceiling does have drywall on it. And yes the cracked ceiling is drywall as well.

Answered 6 years ago by nphall205


It almost sounds like the house is spreading, or something is causing the ceiling joists to sag. How much is stored in the attic above, a lot of books? My first thought was improperly fastened joint between the rafters and ceiling joists causing the exterior wall to bow out and pull the ceiling joist with it but for the crack to show in the ceiling there would have to be a splice or a center beam in the LR that is allowing the joist to move with it and pulling the drywall with it. There would also be cracks in the corners of the wall that would show the wall is moving. There are a few things you mentioned such as the fireplace that would be things I wish I could look at first hand. It could be no support at the ridge,which if the rafters were cut correctly is not even needed but if they were not tight joins could cause movement.

It really sounds like you needeither a knowledgable contractor or a structural engineer to look in to this if it keeps growing or for just the peace of mind it will give you.


Answered 6 years ago by ContractorDon


Could you give me some idea of what it would cost to just have someone come inspect it and give me an estimate of repair costs. I am planning to sell this home asap, sadly I am in dire straits financially and will be unable to pay for repairs. I will have to sell this home 'as is' but I need to know what the problems are before selling. I live in SC.

Answered 6 years ago by nphall205


Not knowing what the rates are in your area I would guess around $300 to $600 for an inspection for just this problem. If you want a written report for the whole house it may go as high as $1,000. Make sure you do get a written report that you can show prospective buyers. I would go with a licensed engineer and not just a home inspector unless you stat requires home inspectors to be certified. Even then I would probably use an engineer. In my state if a home inspector make a mistake they are only liable for the cost of the inspection and not the costs to fix what they missed. Had one case where they whole back of the house had to be excavated to a depth of 13 feet under the basement floor and under pinned with 126 yards of concrete less than a year after the home was purchased.

If the crack does not change with the change of seasons you could possibly get the repair (tape,spackle and paint) for around the same amount. Kind of dirty pool but many do it.


Answered 6 years ago by ContractorDon


Thank you so much for all of your input and help with this. You have given me a good sense of the direction I need to go to deal with this situation. Your advice is greatly appreciated.

Answered 6 years ago by nphall205


Something Don said led me a different way than I was originally thinking - if this crack if across the middle of the room more or less, then that is what I was thinking in my first response.

On the other hand, if it is along the junction of an interior wall and the ceiling, ESPECIALLY if on an interior wall more or less in the center of the house running parallel to the ridgeline, then it is most likely due to joist or truss lifting, which was one of Don's suggestions. I won't go into the cause in depth - basically, in the dry season the attic wood dries out and shortens a few percent, which if you have trusses for roof support OR rafters with a mid=span V or Post connected from the joists to the rafters near the ridge, the shortening causes the middle of the joists (the horizontal "floor beams" in the attic which the living space drywall ceiling is nailed up to) to lift up, lifting the ceiling off the interior walls in the house. This causes a crack to open up at the top of the wall (and rarely breaks the ceiling drywall), and would also of course leave a gap above any crown molding. Assuming you can assure that is it due to ceiling lifting and not floor sinking by checking that the floor does not bow down dramatically (more than maybe the 1/2 inch or so that would e normal for floor joist creep) toward the middle of the house, and that the floor joists exposed in the basement/crawlspace are not damaged or significantly bowing down, then this is NOT a matter for concern. It can be prevented by certain construction techniques, but after the fact about all you can feasibly do is caulk the crack with a flexible, non-hardening silicone modified PAINTABLE latex caulk, using a wet finger to smooth it in against the wall and ceiling. Then paint to match wall/ceiling. I would use spackle or joint compound rather than caulk with your large size crack to initially fill the crack, then when it cracks again use caulk to fill the much smaller crack that opens up - it may or may not recrack (typically in mid-wall, away from adjacent walls that are nailed to the joists) - in some houses it reopens pretty much every year, especially those with very hot dry summer attics and homes in areas with extreme cold, where the outside (and attic) humidity can drop to 10-20%.

My guess is, if this is a midwall joint crack, that the crack appeared either after a very unusually dry summer or unusually cold, dry winter; or after a reroof job - because new shingles are generally far lighter than 1970's ones, the roof rebounds some when they are replaced.

While the crack itself would be considered an architectural defect in an inspection and they might demand repair based on a home inspector's report, the fact that this is happening would NOT be considered a defect in that age house (though it would be in a new home where it could have been prevented with proper technique) - just normal behavior in wood joist and truss construction.

If what I have described above is the case, as long as it is not opening up significantly (more than pencil point width - about 1/8" or less) after patching I would call it good and not bother with an inspection to determine the cause. If this is not the situation, then my prior remarks stand and I would recommend an inspection.

Good luck with your sale.

Answered 6 years ago by LCD

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