How Quickly Does Rising Damp Spread?

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Rising damp can be a particularly destructive problem. It can cause mould, ruin walls, wreck plaster, and lead to serious health problems if mould grows from the damp. Rising damp also spreads. It can leach its way up a wall, making the problem worse before you even catch it. It is caused by moisture and salts in the ground rising up through a wall. Moisture rises into the brickwork. This moisture then soaks in, causing damp on your internal walls, and ruining the interior side.

Rising damp can spread, and fast. The moisture can take some time to become visible, taking months or years before symptoms like damp become present. Once established though, the mould and damp can spread much quicker.

The mould that the moisture causes spreads very fast in the right conditions. The rising damp itself will spread and rise over the course of a few months if left completely untreated. Over a few months, it can rise up to 1.5m if nothing is done about it.

What Affects the Speed of Rising Damp?

Rising damp spreads quick, but a few things decide that speed. This form of damp rises through holes in mortar, cement, and bricks. They draw water upwards where they become moist. The speed of rising damp depends on what you do to slow it and how vulnerable your walls are.

The damp itself is going to spread if left untreated, but it will do so slower if you take some measures to stop things. If left alone, it will go about as fast as the moisture levels and your bricks and mortar will actually allow. It depends on how well your walls have ben damp-proofed in the past.

To slow down rising damp, you need to try and deal with the moisture before it soaks into your walls and becomes damp. While fixing the issue with your walls is the overall solution, you can use good ventilation to mitigate the problem in the short term.

You need to allow the moisture to circulate in your air, particularly low down. This will mean keeping air flowing around a basement if you have one and removing things from the base of the wall at the floor. This can slow down the spread of rising damp but not stop it.

How Can You Spot Rising Damp Early?

Since rising damp gets worse the longer that you leave it, you need to spot it early. You should watch for symptoms on the exterior of the wall. You can’t exactly shove your head into the wall to take a look at the tiny holes themselves, so you’ve got to watch for some key symptoms. These are the key signs of rising damp:

Smell – The smell of damp is pretty easy to pick up on, keep a nose out for this.
Damp Patches – Of course, one of the tell-tale signs of damp is things being actually damp! Damp patches at the base of the wall are the clearest sign.
Mould – Mould will develop on the damp patches if rising damp has gotten into an advanced state.
Rotting Wood Frames – Moisture spreading up a wall will soak into the wood and cause it to rot, keep an eye out for this.
Warped Skirting Boards – Water is going to have this effect on your skirting boards over time.
Paint Peeling off – Moisture will result in the paint peeling off affected walls eventually.
Mould on Furniture Against Walls – Mould can spread to furniture that is pushed against a damp wall.
Plaster – Plaster will bubble and crack when the wall behind has a problem with damp.
Tidemarks on Walls – This is the easiest sign that rising damp is your problem rather than condensation. These tidemarks will show how far the moisture has risen in your wall.
White Chalky Substance on Walls – This is caused by the moisture in your walls bringing salt upwards, which turns into a white chalk-like residue.

How Can You Prevent Rising Damp?

Preventing rising damp entirely can be a bit complicated. It requires quite a bit of knowledge over the health of your walls. This can be a bit of an issue if you’re in an older house.

Prevention of rising damp is easiest done. When building a house in the first place DPCs are added as physical barriers to rising damp. However, over time even these can fail and allow some moisture to get in and become damp. When trying to prevent rising damp in your walls, you can install a course of damp proofing treatment yourself. Since you need to remove the plaster to do this, plastering is a great time to put a course of DPC in.

How to Fix Rising Damp

How can you fix rising damp? There are a few ways to fix rising damp.

Add a new DPC. This is a big job and will likely require the help of a builder. It could also be quite expensive.
Adding a chemical DPC. This is much simpler and can be done as a DIY project. You can read more about chemical DPC injection here
Your final option is damp proofing rods. This is the easiest option, if you can drill holes, you should be able to do this yourself.

Below you can see the steps required to install damp proof rods yourself:

Remove the plaster from the wall so you can get at the brick and mortar, along with getting rid of any damp, or mouldy areas.
Figure out how thick your wall is. You’ll need this information to make sure you treat the entire wall inside safely.
Drill holes into your wall’s mortar. This should be on the horizontal joints rather than the vertical. Drill them 150mm apart, 150mm up the wall.
Make sure you don’t drill through the entire wall. If your wall is 10inches thick, drill around 8.5 inches in!
Use a hoover or compressed air to get any debris out of these holes. This step isn’t essential, but it helps you do a cleaner job of the entire removal.
Cut damp-proofing rods to the size of the holes you’ve drilled in the wall. These work really simply. Once inside your wall, they release a silicone material that fills holes and gives you a layer of damp proofing. This substance reacts to moisture, so it works to remove your damp and stop the damp from rising in the future.
Cut the damp-proofing rods into the proper size for your holes.
Insert the rods into the wall.
Seal up the holes that you drilled.

This solution isn’t instant. It takes a little while to get to work, and one course of damp proofing alone isn’t always enough to permanently stop the problem. Sometimes you’ll have to repeat this. However, while slow, this method does work and it is a solution you can enact yourself, relatively easily.