Why is a Cool Basement Often Damp in the Summer?

by Charlie
Why is a Cool Basement Often Damp in the Summer

Having a basement is undoubtedly an asset in most cases, because they offer extra storage or living space without taking up additional room on your plot. They can be converted to extend the home, or simply used to store bulky household items like washers, dryers, and more. However, they have a significant drawback: dampness.

Dampness in a basement can be a real problem, whether it’s coming through the walls or forming for other reasons. Nobody wants to be dealing with dampness, because it leads to mold issues, and could even cause structural damage. Most of us associate dampness with winter, but what do you do if your basement is damp during the summer?

Why is a cool basement often damp in the summer? Dampness during the summer tends to be caused by humid air coming in through open windows and condensing in the cooler basement. This leaves water droplets on everything, and makes the basement feel damp and uncomfortable. It can cause a lot of problems if it isn’t addressed promptly.

Why Do Basements Get Damp in the Summer?

Dampness in your basement during the summer months is generally a result of condensation. The outside air is often pretty humid and warm. When this warm air enters your basement, which is cold, the water vapor that the air contains condenses back into a liquid, making the basement feel damp.

This will often happen on metal and stone, since these tend to be the coldest parts of any room, and you’re likely to see droplets on pipework or unfinished stonework in the basement. It may look like dew or rain forming on these surfaces.

You might also notice a damp smell, or a creeping feeling of dampness. The carpets may start to form mold spots, or you might find that items that have been stored in the basement get damaged by the excess moisture.

These are all concerning signs, and you’ll need to take action. Start by drying anything you have found that feels wet, and then begin looking for the solution. If the dampness seems to be happening during the summer, condensation is almost certainly to blame.

How Can You Prevent Summer Dampness in Your Basement?

Fortunately, there are quite a few things you can do to tackle dampness in the basement. One of the first and simplest steps involves closing the windows, especially on humid days. A lot of people open the windows, thinking this will create a drying breeze, but it only works if the air itself is dry.

In many cases, it will instead introduce more moisture to the basement, as the warm air blows over cold pipes and steps, and the vapor in it condenses back into water. You should therefore aim to keep your windows shut, except on very dry days. This is particularly true if you live somewhere with humid summers.

Next, avoid using a sprinkler in your garden, especially in the area around your basement. This will increase the amount of water in the air, and this air can then get into the basement. Try to only water your garden when you really have to, and choose days when it will dry out reasonably quickly.

You should turn on your air conditioning system when you can. This will introduce a flow of dry air, which will help to pull moisture out of the basement, but will not add more moisture (as opening a window might do). You might also want to try a dehumidifier, as this will help pull water from the air and leave it drier overall.

This is particularly important if you notice any dampness spreading in the basement; take prompt action. A dehumidifier isn’t a long-term solution, but if you know the dampness is just being caused by humidity (and not, for example, external moisture seeping in), it’s worth trying.

You should also check that the moisture is not originating in the basement. If you’ve got a dripping tap, or if you use your washing machine frequently, you may find that your setup is causing internal moisture to form.

What Other Solutions are There?

Because the condensation is caused by your basement being cool when the outside air is warm, heating the basement up may help. This does not mean you should be running your heating in the middle of summer, but it may mean looking at insulation options.

For example, insulating your walls or stone steps might reduce the amount of water that settles in the basement, and make it a more comfortable and practical space. Pipes can be wrapped in foam or fabric to make them warmer, and this might also make the room feel more comfortable.

It’s also a good idea to regularly check your gutters and drainpipes to ensure they are clean and fully functional. This is true throughout the year, not just during the summer months. Clear away any leaves or other debris that has got into them so they can effectively funnel water away from your basement.

What If the Dampness Continues?

If you continue to experience issues with a damp basement in the middle of summer, you should get an expert to come and assess the space. They will be able to identify if there is a problem with the walls or the floor, and they will look at whether any foundation cracks need sealing.

Regardless of what they say, they should give you suggestions that will help you tackle the extra moisture. In some cases, you might be able to do this just by changing your behavior – for example, leaving your windows shut on particularly humid days.

You can often save yourself a lot of trouble by asking an expert for their advice before you start trying to solve the problem yourself.

Final Thoughts

The summer months can cause dampness if your basement is cold, because the water vapor in the air will condense back into water when it hits cold spots within the basement. This water then lingers, unable to escape (especially if the window has been closed), and may start to form mold and mildew.

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