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We discuss the most efficient way to fix cracks in ceilings, the cost of the materials to do it, the cost to hire a contractor and DIY tips.
Cracks in ceilings? It reminds me of when I was a child lying in bed at night listening to the creaks and groans of the old house. I was petrified, thinking a monster was coming to get me. Mum and dad would gently explain as they tucked me back into bed that there wasn’t a monster; it was only the house settling. Well today’s article is about that. No not monsters in the attic, but the house settling and drying out and causing cracks in the plasterwork.
If you want to know how to recognise when a crack is just a crack or is caused by something more serious then we will have to go through the motions of understanding how and why they occur. We will also need to know:
We also want to have a little lesson in how to repair your cracks as a DIY project and how much it will cost if we call in a professional. Never underestimate the power of YouTube. There are many hundreds of videos available to watch which will explain all about the steps to be taken when repairing plaster cracks and we will be recommending some of these to help you sort things out.
All structures move slightly and it is a good thing they do otherwise buildings would crack and break at the first vibration. Sometimes the movement can be a little more than we would want and cause visible cracks in the surfaces, especially in the ceilings. Cracks in the ceiling can be caused by many different causes. Some of them are serious and some are not. Let us run through a list of the different causes and later on we can see if we can come up with some kind of pattern to the phenomenon.
Movement of the house caused by the wind. The wind outside your house blows against the outside walls and roof. The force applied by the wind varies as the wind speed varies and subsequently causes the house structure to twist, deflect and deform. Normally the amount of deflection is minute and is absorbed by the flexible components of the house such as the timber in the roof, floor and ceilings. Sometimes however the deflection becomes large enough to be noticeable and the brittle parts of the building; plasterwork, mortar and concrete are put under enough stress for them to crack. The crack is just a way for the building to release the stress and settle down into a relaxed state. The weakest part will always crack first and the strongest will crack last. That is why cracks in the plaster are most common. If we had cracks in the brickwork and concrete then there would be a major problem.
Temperature variation between day and night. When things warm up they expand and when they cool down they contract. Different materials expand and contract at different rates. So, what this means is that during the day every item included in your house structure warms and expands slightly. The different materials needed to build a house include, metal, brickwork, wood, concrete, plaster and stone. All these expand and contract to different degrees and at different rates. So to give one example, if a sheet of plasterboard (drywall) has been nailed to wooden studwork and subsequently plastered, you have three different materials bonded together and being forced to behave as one. It is obvious that those three materials are not going to expand at the same rate or at the same time, some taking longer than others. The result is a cracking of the bond between the different materials.
The house drying out. When the house has been newly plastered indoors, the gypsum powder will have been mixed with water to produce the pliable paste necessary to bond onto the wall or ceiling surface. Once the plaster has been spread (or laid) and before the plaster can be painted, it must be allowed to dry out. Many gallons of water have gone into producing the plaster necessary to cover the walls and ceilings of a normal living room. The plaster surface will be touch dry in a matter of hours but the whole layer of plaster can take many days to completely dry out. To prevent cracks forming in the plaster it must be allowed to dry out slowly, but this is not always possible. Economic pressures are always forcing the construction team to finish the work as quickly as possible and an inaccurate assessment of how dry the plaster has become will mean the surface is painted quicker than it should be.
The result will be that the plaster dries out at different rates throughout its depth causing a crack to appear, usually along a line of weakness such as a plasterboard join or a course of bricks. It isn’t only new houses that dry out too fast either. Older houses are continually drying and becoming damp again especially if you have a faulty damp proof membrane, leaky roof, faulty plumbing or just had a new central heating system installed. The nett result is for different rates of drying in different locations causing cracks.
Foundations. All houses are built on foundations, some more effective than others. The purpose of the building foundation is to give a strong immobile base to the building to prevent subsidence and other collapse taking place. Usually the foundations are made from a continuous concrete ring poured around the circumference of the house and below all loadbearing walls. The concrete is supported by the subsoil or bedrock deep within the ground. Subsoil is made from compressed particles of clay, sand and silt without the large percentage of organic and humus that topsoil has. As such, subsoil is very stable and is usually perfectly ok for providing support for foundations. Likewise bedrock is solid and immovable and perfect for foundations. Or are they?
Bedrock can be upset by minor earth tremors and forced to crack to relieve the stress build-up. These tremors are surprisingly common and happen throughout the world, some areas more than others. The concrete foundations are bonded immovably to the bedrock so if the rock cracks, so will the concrete. Result is subsidence.
Subsoil is normally compressed so much that it is quite solid and stable. Sometimes however if the local water table rises or an underground stream is diverted, the movement of water can gradually wash the particles of subsoil away until the concrete foundations cease being supported properly. Result is subsidence.
Subsidence means uneven support of the rest of the house and is a very serious problem which needs a structural engineer and a suitably qualified professional builder to sort out.
Different load. Over the years your house has aged gracefully, most of the settlement cracks have happened and been repaired and there has been no movement for years. Then your roof fails, your slates or tiles start to crack and you decide to have a new roof installed. The roof is stripped back to the bare rafters and you find that some of the wooden rafters are rotten too. There is nothing else for it but to replace the rotten rafters and replace the roofing tiles with new. The job is done and all is once again watertight. However what you forgot is that you relieved the walls and foundations of a considerable weight when you removed the roof. The house expanded upwards because of the reduced load, and then contracted again when the new roof tiles were installed.
The roof tiles were modern ones and each one was a tiny bit heavier than the old tiles. Combined together, the tiny increases in weight have added up to a considerable extra load. Your foundations were designed for a certain load and now you have increased the weight considerably. Most times your foundations have been designed with a Factor of Safety big enough to accommodate the extra weight and you will just have a few months of settlement cracks again. Only a job for the decorator, so no need to worry. Sometimes however the extra weight will cause damage to not only the foundations but parts of the building on all floors as the size of rafters, ceiling joists and load bearing walls will also have been calculated to accommodate the weight of the roof as well. This will often occur if you have done some major construction like building a first floor addition to your house. In this case your foundations have not been designed for this much extra weight and you will find that they crack and serious subsidence occurs. Once again this is a job for the structural engineer and the experienced builder.
Additional weight upstairs. You live in an apartment with people living above and below you on different floors. The single person above you has moved out and a family of four has moved in. They have far more furniture and use all the rooms far more than the previous single person ever did. The result is that their floor joists (your ceiling joists) are being subjected to an increased load which will increase the bend and deformation of the wood in the joists. Because wood is flexible and plaster is not, you will have cracks form in the ceiling following the join lines of the plasterboard sheets.
Age of the house. As a building becomes older, the tiny cracks caused by the continual onslaught of different forces on the house, combine and magnify and eventually become visible. These cracks usually end up as the commonly seen ‘spider’s web’ cracks.
We found in the previous section that different types of load variation can cause different movements, deformations and failures within the house. These movements are usually made visible as cracks in the brittle plaster surface. There are different type cracks however depending on the cause and we will talk about those now.
Very fine cracks. Also known as ‘spider web’ cracks. These are usually caused by the natural aging of the structure. Usually caused as a combination of humidity changes and varying load. Nothing to worry about, these are just cosmetic. Very fine cracks are usually considered to be less than 1/16” wide, anything more than this should be looked at by a professional. Sometimes this type of crack is caused by applying a thick layer of drywall jointing compound to add texture to the ceiling. As the compound dries unevenly, so the cracks run randomly across the ceiling.
A fine straight crack. If you find one of these it is probably caused by a badly taped joint between the plasterboard sheets. When plasterboard sheets are fixed to ceiling joists they are butted up to their neighbours. There is always a small gap between the sheets to allow for natural movement and this is filled by plaster jointing compound followed by a fine mesh tape or sometimes a special gummed paper tape to strengthen the joint. The tape is pushed into the jointing compound and smoothed over. Sometimes the tape does not adhere properly and the joint is not strengthened. This eventually causes a crack to develop along the line of the joint. This is not structural or a safety hazard so can be safely ignored or repaired with a thinly mixed jointing compound or even PVA adhesive.
Vertical cracks. These cracks run across the ceiling and vertically down the wall from the same point. Usually these are caused by a weak wall stud, but sometimes they can indicate problems with the building’s foundations. You need a structural engineer or a very experienced builder to determine what is going on here.
A discoloured crack. Sometimes the indoor plumbing or the roof might develop a slight leak and cause water to trickle down between the joints in the plasterboard. The joint tape may subsequently become loose causing what appears to be a crack along with ugly brown or yellow stains. To repair this crack you must firstly find the leak and fix it otherwise the stain will reappear. Then remove the loose tape and replace with fresh tape and jointing compound. You can buy ceiling repair kits from home improvement centres if you want to take the easy way out. Be aware that although plasterboard (drywall) will resist a small bit of moisture, for long term exposure or in the case of a major leak, you may have to remove and replace either a full sheet or cut out a section and replace it with a patch. Remember to replace the tape on the joints of the patch and cover with jointing compound before decorating the patch to match the rest of the ceiling.
A crack with a bowed ceiling. These are usually caused by a weakness in the ceiling joists or sometimes even a failure in the joist support in the walls. The crack can be either along the joist or to one side of the joist. These cracks are always caused by a serious overload above the crack. They can either be caused by a far heavier roof than was designed for or by adding extra storeys onto a building designed to be one storey. Either scenario produces the same effect. Both of which are very serious and needs to be sorted as soon as possible.
A crack between the ceiling and wall. The ceiling joists and roof trusses have been designed to move up and down, and expand and contract with changes in humidity and temperature. As the wood moves so the drywall, fixed to the wood, moves with it. If the drywall is nailed to the joists near the wall then the movement will cause a gap to open up against the wall. The answer is to stop fixing the board to the ceiling when near the wall, instead nail the boards to blocks or battens fixed to the top of the stud walls. This is not a structural problem but it can look unsightly. The crack can be left alone or covered with a decorative coving. The coving should only be fixed to the stud wall to continue to allow movement between the ceiling and the wall.
Vibration cracks. If you live on an estate that is still being built, live near a busy road or airport, or live above an underground railway, you will experience vibration from the continual movement of heavy traffic and large vehicles. This vibration will cause your house to move slightly or vibrate in sympathy with the outside traffic. The vibration can cause cracks to appear. The type of crack may be a simple cosmetic type or it may be caused by interference with your foundations. This type is definitely worth contacting a professional to give an opinion.
Cracks can occur anywhere on your ceiling:
If the cracks occur near the edges of the ceiling then they will most likely be caused by aging and settlement. If they are in the middle of the ceiling and consist of multiple, wide and long cracks then they are of more concern and should be looked at by a structural engineer or experienced house builder. It is also worth monitoring the crack to see if the layout changes, by how much and how fast. If the cracks seem to be randomly distributed then it is likely that the cause is a minor one. All this information will be useful to the professional so keep a journal of how and when they change and make a note if you see any relationship with outside influences.
When you have identified a crack in a ceiling that you think might be caused by something serious, you will need to see if the crack widens, lengthens, changes direction or generally moves. Sometimes the surfaces either side of the crack can move out of line too. Length of crack is simplest to note; simply mark on the ceiling the start and end using a pencil. Also draw several lines across the crack at various positions, these are called alignment marks, this will show if the changes are regular or uneven. Keep a notebook of dates when measurements are taken and dimensions of the crack on these dates. If you can draw a sketch of the cracks’ appearance on these dates it will be very useful for the professional to see a record of any changes in appearance.
If you find that the crack is growing wider, longer or if another crack has appeared it will be worth contacting a professional to assess any damage and determine the most probably cause.
If the cracks are simple cosmetic cracks that are not caused by subsidence or problems with load bearing walls then it may just be simpler to buy some decorator’s caulk or crack filler, repair it and redecorate the crack yourself. If however the crack is caused by a structural problem then you will have to get your household insurance company involved. Depending on the terms of your contract you may be able to have all work done to repair the fault paid for by the insurance company (minus any excess payment of course). It is always worth contacting them anyway because if you have a mortgage you will probably have to contact your mortgage lender to inform them of the problem and the steps you are going to take to provide a solution.
The majority of cracks in the ceiling are caused by settlement in the house and expansion and contraction of the building materials during the settling. These cracks are easily repaired with a few simple tools and materials.
Ok, you have repaired a simple crack in the ceiling but it keeps on returning. You have checked to see if there is any major hidden problem causing this, but no, it’s ok, it’s just a crack. Phew! What then can we use to help prevent the pesky crack from returning?
There is a product on the market, and you can buy it in home improvement centres as well as online, and it is called ‘Good-Bye Cracks’. Not a particularly original name, but hey, if it works who cares.
Sometimes the crack is so bad that you just can’t repair it at all. This tip works not only for cracks, but also if you have a piece of damaged drywall, say from a plumbing leak or a hard knock. In this case the best thing to do is to cut out the offending area and install a patch. No matter how good your patch is, it will nearly always show unless you have the whole ceiling or wall skimmed with plaster. You can buy a very heavy duty lining paper to cover your walls which when painted effectively disguises any cracks and patches you may have.
While we are talking about patching drywall, you need something to screw the patch to. You can always do it the traditional way by screwing a partially overlapping wooden frame (made from batten) behind the patch opening or you can buy drywall repair clips and use those to support the patch. Just follow the instructions on the pack.
If you want to, you can cover over any imperfections with a textured finish. This even works with fine cracks without being repaired. There are three ways of doing this:
Buy a hand pump texture gun from home improvement stores or online and spray on a layer of texture. You can buy purpose made texture or just water down some jointing compound. The texture gun needs practice to finally get a good finish so practice on cardboard first.
Now this one is really simple. Use exterior textured wall emulsion paint to paint your cracked drywall. The texture hides any imperfections on the drywall and provides a good painted finish at the same time. Apply the paint with a foam or lamb’s wool roller for the best finish. Be warned, most external emulsion paints contain special water proofers and fungicides which give off fumes as they dry. Ventilate the room well until the paint has dried completely.
If you just need a small repair making good, then buy a tub of ceiling patch and dab this on it. It works really well on popcorn textured ceilings and you can just add more if you want.
If you have a stained ceiling as a result of water leaks, then you need to cover the discolouration with something before you use emulsion paint. You can buy an aerosol stain blocking primer in good home improvement centres but why not just try brushing on a couple of coats of oil based primer or undercoat paint. Once the undercoat is dry you can paint over the top with normal emulsion to match the rest of the ceiling. Don’t be tempted to use a gloss finish oil paint as the stain blocker because the emulsion will not bond to the gloss.
Another way of patching ceilings that is available to buy is known as ‘instant patch’. These are self-adhesive metal patches that just stick over the damaged area. Once it is stuck you use joint filling compound and mesh tape to blend it into the rest of the area. These are sold in sizes ranging from 4”x4” to 8”x8”.
What are you going to do if you aren’t able to do these repair jobs yourself? You might be too old or infirm to climb up a ladder to your ceiling or you may just not have the time. Whatever the reason, you must realise that you can always call in a contractor to do the work. There are a number of contractors qualified to repair drywall and whichever one you prefer to call will surely give you a good quotation. Some of the contractors you could call would be:
All these people will have the experience and tools to complete your job to a satisfactory standard so it is up to you to find someone suitable.
Ask around among your friends and family for names of suitable candidates. You never know, someone you trust may have already had some work done by a suitable person.
Try to find about three or four different contractors or companies and then start to do your homework.
There are many factors affecting the cost to repair your damaged ceiling. Amongst the most common are:
The ceiling’s condition. If the condition of the ceiling is bad to begin with, then a few crack repairs won’t really make a lot of difference. Have you considered having a full replacement ceiling?
If the existing ceiling is made from drywall (in the UK this is called plasterboard), then what is needed is for the existing drywall sheets to be pulled down and replaced.
If the existing ceiling is made from lath and plaster then you can still pull it down, but the job will be dustier and make more of a mess.
Before you attempt either of these it is a good idea to remove all the furniture, roll up and store the carpet somewhere safe and seal all internal entrances to prevent the spread of plaster dust within the house. Don’t forget to protect yourself as well by wearing a dust mask and safety spectacles.
Internal and external corners. If you have to replace the ceiling then you will have to cut the drywall sheets to fit around internal and external corners and projections along the walls. If the required work is just crack repair and they are clustered along the edge of the ceiling by the wall/ceiling junctions, then you will find that there will be more work if you have more than just four internal corners like a simple ‘box’ shaped room.
Size of the room. You often find that larger ceiling areas have more cracks. This is because the length of span of the ceiling joist will accentuate and amplify any vertical movement (or bounce) by the joist. As we discussed earlier, cracks can be caused by the vertical movement of joists when they reach their maximum unsupported span.
The ceiling surface style. The ceiling surface may either be very well plastered with a smooth finish or have an ornamental texture or pattern to it. Either one will make invisible repairs very difficult to do. You may have to hire a skilled plastering contractor to provide a first rate repair or you may have to consider changing the ceiling surface to one which is more conducive to hiding mediocre repairs. A random texture pattern is good for doing this.
Quality of product. As we discussed elsewhere in this article, there are many different ways to make a ceiling repair. Different methods require different products and each of those have their own pros and cons. Some products are designed for the quick fix DIY market while others are designed for the good quality professional. It is up to you as to which type of finish you require and which quality you will be happy with.
Access. The question of how easy it is to access your ceilings will have an effect on the cost to repair them. Most modern houses have rooms of about eight feet high. If you live in a period house or one that is a converted commercial building you may have ceilings that are higher and very difficult to get to. You may need scaffolding erected to allow access. This will add to the cost of the job.
Contractors. The type and experience of the contractors will affect the price considerably. As a general rule, handymen will probably be less expensive than carpenters and drywall contractors, but this may not always be the case. Expect some variation in the quoted prices. The contractor’s rate will also vary depending on how much work they have and what time of year it is. All contractors tend to prefer outside work during the warmer months and inside work during the wetter and colder months. They will therefore tend to be choosey when it comes to working on an indoor ceiling repair.
The costs to buy materials for repairing or patching cracks and other damage will vary depending on where you buy them. Often you can buy cheaper versions of the more expensive branded products so keep your eyes open for possible bargains, especially from discount warehouses and online retail stores.
|Good-Bye Cracks||4oz. spray||$12|
|Wall Liner heavy duty wallpaper||396”(33ft) x 20.5”||$22||Prepasted|
|Smoothing tool||each||$5||For applying wallpaper|
|Drywall finishing tool set||set||$60||Incl. Stainless steel mud pan, taping/jointing knife, sanding sponge, mud mixer|
|Drywall mesh tape||300ft x 2” roll||$6||Fibreglass mesh, self-adhesive|
|Drywall repair patch||8” x 8” single patch||$5||Self-adhesive, aluminium|
|Drywall repair clips||Pack of 6||$5|
|Drywall backing plates||Pack of 200||$55||Plastic|
|Spray texture touch up kit||each||$15||Incl. Sprayer, small mud knife, premixed spray texture|
|Popcorn ceiling patch||1 Quart tub||$10|
|Gypsum jointing compound||1 Quart||$12|
The cost of hiring a contractor will vary depending on the area of the country in which you live and the contractor’s speciality. Typical rates are shown in the following table.
|Hourly rate||Typical range|
|Average cost to repair a ceiling||$325 to $1,030|
|Average cost to hire a carpenter||$60 to $300 per hour|
|Average cost to hire a decorator||$60 to $120|
|Average cost to hire a drywall specialist||$60 to $90 per hour||$270 to $750|
If you are intending to repair the cracks in your ceiling or replace the drywall sheets then there are a few safety considerations you must follow.
Plaster dust will be produced when you clean out the cracks, sand down the surfaces and when you mix dry powder with water. Although the powder in itself is probably non-toxic, it is alkaline and the presence of dust in your lungs will not do them any good. If you are tearing down an old ceiling then lots of dust will be produced which will do you no good at all to breathe in. Old ceiling lath and plaster tends to contain horsehair for bonding purposes and many decades build-up of bacterial and fungal spores.
Dust floating around in the atmosphere has a habit of ending up irritating your eyes. Plaster dust particles are not only of such a small size that they will irritate, they are also alkaline so will greatly add to the irritation. When mixing plaster dust with water to produce workable slurry, be careful that splashes do not land in your eyes.
Gypsum plaster is alkaline so try to avoid having direct contact with your skin. Always wear protective gloves.
You might need help accessing the ceiling to work safely. Take care when using ladder and scaffolding as even falling from a height as little as four feet from the ground can cause serious injury.
Working with wet plaster is dangerous if you are near exposed electrical cables such as ceiling light fittings. Be careful of touching and cutting cables with metal trowels and remember that water conducts electricity.
When producing dust always ventilate the room as much as possible and clear up regularly.
Today we learned about ceiling cracks. There are two types of ceiling crack, those that are purely cosmetic and can be easily repaired and those that are caused by something more serious. The latter cracks should not be repaired until the underlying cause has been fixed. It will take the skills and experience of a structural engineer to determine the causes of these cracks and need the skills and experience of a construction contractor to repair the causes. Once those have been fixed then the cracks can be repaired.
The other type of crack can be repaired either yourself as a DIY project or by a contractor. We talked about the different types of contractor whose skills would be acceptable when dealing with ceiling cracks.
There are various products available to buy when repairing ceiling cracks and each one should only be used for its specific application as specified by the manufacturer.
When using the commercially available products always follow the manufacturer’s instructions and follow some simple, basic safety procedures to ensure you and your family stay safe.