How to fix a damp ceiling – Should you replace or repair?

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how to fix a damp ceiling

Damp can occur anywhere in our homes and it can be caused by a variety of factors. However, a damp ceiling can be a particular area of concern. After all, nobody wants their ceiling falling through and this is a very real risk if there is major damp present.

Fixing damp on a ceiling is usually quite a simple process. The first thing you will need to do is stop whatever is causing the damp.

Once the underlying issue has been repaired, there are two main courses of action you can take:

  1. If the damp is minor, you may get away with drying the area out and redecorating.
  2. For more serious damp, you will need to replace the plaster board. Depending on the extent of the problem, this could involve a small patch, a full board, or even a full ceiling.

Finding and fixing the damp issue

Before you do any work on the ceiling, you will need to figure out what is causing the damp. This is usually quite simple, as there are only a few possible causes.

First you need to consider which floor you are on and what is directly above you. If you are on the top floor, then a roof leak is a potential issue. Alternatively, if you are on a lower floor, then this is far less likely.

If you have ruled out the roof, next you should look for other potential leaks. Below are a few things to consider:

  • Is the damp on your ceiling below a bathroom? If yes, you should inspect the pipes behind your bath, shower, sink and toilet. Are there any leaks?
  •  Check all the radiators for potential leaks.
  • Look for any burst or weeping pipes (this may require you to lift floorboards).
  • Consider where the damp is located. If it is towards the edge of the room, it could be penetrating damp coming from outside.

Once you have identified the cause of your damp ceiling, you should completely fix the problem to avoid it returning in the future.

What if you don’t know the cause?

If you are unable to find and repair the issue yourself, a good solution would be hiring a local trades-person to find and fix the problem.

Who you hire, will depend on where the water is coming from.

For example, if you think it is caused by leaking pipework, you should hire a plumber. For issues with the roof, a roofing contractor, and if you suspect penetrating damp, then a damp proofing company will be your best choice.

However, if you are completely stuck and have no idea where it is coming from, a local handyman may be the best choice.

Handymen are usually more affordable and will be able to locate the problem for a small fee. They will also be able to carry out most minor repairs. If the problem is more serious and beyond their area of expertise, they will usually be able to point you in the right direction of a more specialist trades person.

If you don’t already know a good trades-person for the job, the best way to find one is via an online comparison site. These sites allow you to compare local professionals and read past customer reviews.

They also tend to work out much cheaper than calling local companies direct, as they all know they are competing for the same jobs.

To get up to 5 local quotes from handymen, plumbers, roofers, or any other job you need doing Click Here.

How to repair your damp ceiling

Once the underlying cause of damp is fixed, you can start to repair the ceiling. At this point you will have two choices:

  1. Dry out the damp patch and redecorate
  2. Replace damaged plaster

If the damp is very minor, you may get away with drying out and redecorating. However, it is important to realise, that even a small amount of water can cause plasterboard to deteriorate quite considerably.

Assessing the damage is usually quite easy. You should look for any obvious sagging or swelling in the ceiling. If either of these are present you will need to replace the plasterboard.

You can also check the plasterboard with a bradawl or small screwdriver. If it is soft and the tool inserts easily, this is another sign that the board is damaged beyond repair and needs replacing.

The area of plaster you replace will depend on the level of damage. In some instances, you may be able to cut out a section with a pad saw and patch with a small piece of new board. If the issue was bigger, you may need to remove an entire board, or even the whole ceiling.

All of these are jobs that can be achieved with some DIY knowledge. However, boarding a ceiling is heavy work and you will need two people to replace full boards or a whole ceiling.

It is also likely you will need a plasterer to skim the ceiling following the new boards. If in doubt, it is recommended that you just hire a plasterer to do the entire job.

Again, you can find good local plasterers quite easily online.

Click here to view plasterers in your area

What if your damp ceiling is old lath and plaster?

If you are in an older property it is possible you don’t have modern plasterboard in your ceiling. Instead, you may have lath and plaster.

If this is the case, you have two options:

  1. Pull down and replace with plasterboard
  2. Completely dry out and overboard

In most cases we would recommend the latter. Removing lath and plaster is possibly the dirtiest job in the entire building trade. The amount of thick black dust it causes is significant and if you are living in the property, removing the ceiling should be a last resort.

If on the other hand, you are refurbishing a property, pulling down and replacing is an option. Just be warned, it is a filthy job and very unpleasant. It is recommended you use masks, goggles, and even protective suits to stop the dust.

Following this there will be a lot of clean up. In many cases you will wish you just over boarded.

Basically, if you have the choice, leave the old ceiling up and fix boards over the top.

Depending on the thickness of your ceiling and new boards, as well as the amount of sag in the ceiling, this will determine the length of screws you need. Anything between 50mm and 75mm will usually do the trick.

In most cases the new boards will pull right up and eliminate any sag that exists in the ceiling.


In most cases fixing a damp ceiling is a simple job, but you should always make sure you fix the cause of damp before you carry out repairs. Also, if in any doubt hire in professional help, especially for heavy work like boarding ceilings.

Finally, if you do have old lath and plaster ceilings, it is highly advised you ovoid pulling them down where possible.

Pulling old ceilings down is not a fun job. You will quickly regret it if simply over boarding was an option