Is damp on a ceiling dangerous?

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is damp on a ceiling dangerous

Whenever you notice damp anywhere in your home, you should always try to resolve the issue sooner rather than later.

Most problems caused by damp are cosmetic. However, in some instances it can cause more serious issues, such as damage to brickwork and structural timbers.

Damp ceilings are another area that can cause problems. When only small levels of moisture are present, there will usually be no issue. However, if the ceiling is holding a lot of water, then there is a risk of it falling through.

Also, following damp exposure there is the future risk of mould growth, which can cause further problems.

Are Damp plasterboard ceilings dangerous

In most modern properties, ceilings will be made of plasterboard and skimmed with a finishing plaster.

The boards will be fitted to the ceiling joists above. This is generally done with dry wall screws, which are screwed into the boards at regular intervals, fixing to the timber joists.

Screws are usually fixed in 200 – 300mm intervals, along the length of each timber joist. This means that when your ceiling is dry and free of defects, it will be very sturdy.

The problem with plasterboard, is it is extremely porous and takes on water very easily. Once the board becomes saturated, it can also take a long time to completely dry out.

Even if you do manage to dry the board, it will have lost a large amount of its original structural integrity. The material in the board will swell and start to sag. At this point you may even notice small depressions in the surface, where the fixings are starting to pull through the damp plaster board.

The main problem here, is the screws are the only thing holding your board up. If the board is weak around the fixings, its weight can cause it to pull through and come away from the joists. At this point, there is a very real danger, of this section of the ceiling falling through.

With all of that said, most ceilings will be able to handle a small amount of water, from something like a minor leak. If you can stop the water and completely dry the area, there is a chance you won’t need to replace the boards.

However, you will need to keep an eye out for mould growth, as this can easily spread and further damage the plasterboard’s.

How to replace plasterboard in a ceiling

If in doubt, you should just replace the board. It is always better to be safe than sorry. Obviously, you should make sure that the issue causing the damp is also completely rectified.

This could include any of the following:

  • Internal leak (pipes, bathroom, radiators, etc)
  • Penetrating damp through walls
  • Leaking roof
  • Water leaking from another property above (flats)

Replacing a section of board is not usually a big job. Most decent plasterers will be able to remove the old defective board, fix a new one, and skim over in the same day.

It may also be a job that can be done by a competent DIY’er. To do this, you will need to trim back to a point where the board is dry, showing no signs of damage. You can see a short video of someone replacing a small section of board below:

If you don’t have the right tools, or if you just aren’t confident to do the job yourself, hire a professional plasterer.

You can easily find a local plasterer online via local job comparison sites. These tend to be the most reliable and affordable way to hire this type of trades person.

You can check all their previous customer reviews, plus it tends to be much cheaper, because your comparing multiple quotes.

To check out our favourite comparison site and get 5 local online plastering quotes click here

Are damp lath and plaster ceilings dangerous

If you have an older property that has suffered with a damp ceiling, it may be constructed with lath and plaster.

This is an old method of plastering, that is still present in many properties throughout the country. Basically, thin timber laths are fixed (usually nailed) to the joists and a lime plaster is applied to the laths.

If you have this type of ceiling and it has suffered badly with damp, the process is not quite as simple.

It is highly likely that you will need to remove the old ceiling and add a modern plasterboard ceiling.

The major problem with this method is the mess. Pulling down lath and plaster ceilings is an extremely messy job. There is usually years of black dust built up, as well as all the lime plaster itself.

If the damp was only minor and you are confident it is completely dry, with no mould, another option is to board over. You could even use foil backed vapor barrier boards as an additional precaution.

However, if there is any doubt about existing damp, or future damp and mould, it’s probably better to bite the bullet and pull it down.

If you decide to do this job yourself, you need to make sure you prepare before you get started. The following are all advised:

  • Dust mask
  • Goggles
  • Full body dust suit
  • Thick dust sheets (cover everything)
  • Open windows for ventilation

Anybody that has done this before, is likely to tell you that this type of job is horrendous.

The dust created is thick and black. I don’t think it is an exaggeration, to suggest this is probably up there, as one of the worst jobs you could ever wish to do.

It is extremely messy, and dust will be showing up long after the work is completed.

Don’t want to do this yourself?

Click here to get 5 local online plastering quotes


Damp ceilings can cause several problems. Most will involve damage to decorations and issues with mould. However, in some more serious cases damp on a ceiling can be dangerous.

In the worst-case scenario, your ceiling could fall through. Therefore, if you are worried about the integrity of a ceiling after damp, it Is probably best to seek the advice of a professional.

You should also make sure that the cause of damp is completely fixed to avoid future problems.