Can a house collapse from damp?

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Damp can cause all kinds of damage. It has the potential to enter your house in many ways. Most issues with damp will be cosmetic, but there is a more serious side and some of the consequences can be quite severe. Especially when left untreated for extended periods. So, can a house collapse from damp?

It is very unlikely that a residential property would collapse due to damp. The structural damage would have to be extremely severe for this to happen. However, damp can definitely cause structural issues, so in theory it is possible given enough time.

We have probably all seen abandoned, old buildings, that have deteriorated over time. Even then they are usually still standing.

One common example is abandoned buildings in farmers fields. These are very common in rural areas. However, they are often just barns or farm buildings. This means they are not usually intended for residential use. But it does show that time and neglect can lead to these types of building collapsing, and damp will certainly play a role in this process.

Types of structural damage damp can cause

can a house collapse from damp

There are two main structural materials that damp commonly affect, these are masonry and timber. Some of the main issues you might find include:

  • Damp floor joists
  • Damage to masonry such as spalling bricks
  • Problems with roofing timbers

Below we will look at each of these in more detail, as well as some solutions.

Damp in floor joists

This is quite common and will usually occur at the ends of joists. In many properties these structural timbers are housed in holes in the external wall. In some other cases, they will be fixed to a timber wall plate with joist hangers. Either way, the timber is in contact with the masonry, so if water penetrates, it can easily saturate the timber.

This moisture can penetrate through a defect in the building, this is known as penetrating damp. Also, in floating ground floors made of timber, they can also be affected by rising damp.

Once the timber becomes damp, it is an ideal place for mould and rot to form. It can also make it appealing to several wood burrowing insects. Including species of woodworm that prefer damp timber.

Any of the above will gradually weaken the floor joists. This can lead to the floor becoming unsafe, where some joists aren’t attached to anything. In the worst-case scenario, it is possible for a floor to collapse if it is left long enough.

How to fix damp floor joists

Fixing floor joists can be a big job. In most cases you should seek the help of a professional. The extent of the repair will depend on the extent of the damage.

If there is only one or two joists affected, you may be able to fix it with less disruption. However, you will still need to remove floorboards. If the issue is bigger, you may end up replacing an entire row of joists. Also, if the problem is above ground floor level, there will be the ceiling from the floor below to contend with.

Affected joists will need replacing or cutting back and overlapping with a new joist.

When overlapping, the two joists will be bolted together and should have a decent amount of overlap each side.

If you plan to hire someone for this job you have two options:

  1. Hire a joiner/carpenter
  2. You can hire a damp proofing company

In most cases the latter will probably be the best option. There is an underlying reason that joists are damp, and this must be fixed before you replace them. If not, the problem will return.

Most damp companies will usually employ regular tradesmen such as joiners. As a result, they can provide a more thorough service.

The best way to hire a damp company locally, is to compare online. Most reputable damp proofing experts will be on trade comparison sites, and this works out even better for you, because the prices tend to be much lower when you hire this way.

Each company is competing for the work, so their quotes tend to be much more competitive. Also, other people will have hired them in the past and left feedback, which can be helpful.

To compare damp proofing quotes in your local area, Click Here

Damp causing structural damage to masonry

Your home is open to the elements and the materials it is made from are often porous. For example, stone, concrete, and bricks can all take on a certain amount of water.

Some materials such as slate have extremely low absorption, hence their use in roofing. However, an old clay building brick could have an absorption rate of up to 35%.

Water will enter building material via small pours and capillaries. For the most part, this is fine, and it is a good thing that your property is breathable, as this moisture can easily evaporate away.

Problems can arise when a surface lets in too much water due to a defect. This could be any number of things, such as a cracked brick, or damaged pointing. When your masonry is holding a lot of moisture it can begin to deteriorate. This is most affected in winter, as the moisture will expand when it freezes and cause the bricks to crack. This process is known as spalling and once water gets in it can spread to other bricks.

Obviously, this can be quite destructive, and it can cause structural issues. However, it would usually need decades to cause any serious structural issue. Even then, the house wouldn’t be anywhere near collapsing.

With that said, it is an issue that needs fixing, and you will need a builder to carry out this work safely. Again, the best way to hire your builder is via a comparison site. This will get you the best local tradesman at the best possible price.

Click Here to get online quotes from local builders

Damp causing structural damage to roof timbers

Another area prone to leaks and penetrating damp is your roof. When your roof is in good condition, it is one of the most protected areas of your home. Roof tiles and slates are often very low absorption materials and water simply runs off the surface.

Unfortunately, even a small defect can allow water in, at this point gravity will do the rest. Often roof leaks are small, slow, and persistent, this means that you might not even know the roof is leaking until it is too late.

Just like other structural timbers such as floor joists, the roof trusses can suffer with damp, mould, rot, and insect infestations.

If you do spot a leak, you should aim to get it fixed as soon as possible. If not, it is not only your roof timbers that could suffer. It could also result in serious cosmetic damage, as water leaks down into other areas of your home.

Roofing is a job for the professionals. Accessing the roof is dangerous without the right equipment. Also, if you don’t know what you are doing, it is very easy to make leaks far worse. Therefore, you should always hire a professional roofer.

To get local roofing quotes and see how much you can save Click Here


Structural damage cause by damp can be quite serious if it isn’t treated. The problem will usually get worse the longer it is left. As a result, the longer you leave structural problems the more dangerous the issue will become.

Whilst it is serious, it is extremely unlikely that damage would get so bad, it could cause a house to collapse.