How Does Humidity Affect the Building Structure of a House?

Excessive humidity can be damaging to the structure of your home. If you live in a climate with higher humidity levels, it’s important to understand what this means to you and your home. How does humidity affect the building structure of a house?

Humidity affects the building structure of a house by penetrating the exterior and working its way inside of your home. An over-excess of moisture buildup in a house leads to the deterioration of the building’s structural integrity such as insulation, drywall, floorboards, and wood. 

How Does Humidity Affect the Building Structure of a House?
Humidity can affect more than you think.

A house needs to breathe, so shutting out 100% of the moisture is not realistic. Yet when there is too much moisture penetrating the inside of a home’s structure, problems can arise.

There are many ways that high humidity can destroy your house.

Knowing what preventative measures to take to avoid moisture damage to your home will save you money in the long run.

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How Does Humidity Affect the Building Structure of a House?

Too much moisture inside a home can potentially deteriorate the home’s building structure, and there are things you need to watch out for.

The most common things that may be affected by high humidity in a home’s building structure are:

  • Insulation
  • Walls/drywall
  • Floorboards
  • Wood damage and dry rot

Insulation in the attic and walls can rot and lose its ability to resist temperature change. Mold can grow on insulation, wood products, and drywall and destroy the strength of these building components.

Besides making walls and ceilings sag and crumble, moisture can rot the wood. During the summer months, the walls of your house may be damp, so they tend to be a perfect breeding ground for mold.

This moisture can also cause the insulation to deteriorate and breed mold. 

When the temperature decreases by even a few degrees, the relative humidity increases. This increases the chances of bacterial, mildew, and mold growth.

It is important to keep your house free of moisture to avoid these problems.

The relative humidity is often measured in percentages, with 100% being the highest. It is a measurement of the amount of water vapor in a certain volume of air.

The difference between relative and absolute humidity is significant, as it is difficult to separate the relative humidity of space from the absolute humidity of the same space.

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This difference in moisture content can cause structural damage to the house.

High humidity can damage building materials. It can cause the rotting and warping of the wood. It can cause water-soluble building materials to return to the solution.

The higher the relative humidity, the more water-soluble the material.

The higher the RH, the more likely it is to become damaged. Greater relative moisture will result in more expensive repairs, more damage, and increased health risks.

The high relative humidity is dangerous because it can destroy the building’s structure.

However, there is no one-size-fits-all solution. The main problem is that the humidity in a building can cause problems.

For example, if the humidity inside the house is over 60%, the moisture will cause mold. Furthermore, it can damage floors, brickwork, and furniture. 

Related Article: What Happens if Indoor Humidity Is Too High?

How Does Humidity Damage Drywall?

There are many ways that high humidity can damage drywall in a home, so it’s important to understand how to prevent moisture in the air from damaging your walls. How does humidity damage drywall?

High humidity can damage drywall causing the paper on drywall panels to swell, buckle, crack, and bubble. This prevents the paint from adhering properly to the drywall which produces an unsightly finish. Moisture can seep into gaps between wall studs and into electrical wiring which can be dangerous.

Humidity damage to walls is the moisture in the air that seeps into porous surfaces. This moisture can cause serious damage if not treated by professionals quickly enough.

The moisture needs to be removed from the wall, and it must be done before the moisture damage spreads to other parts of your home’s structure.

There are a few ways that moisture affects a home:

  • Water penetration from a leaking pipe through holes in walls and ceilings.
  • Moisture coming up from the crawlspace below
  • A roof leak or flooding into your home from outside during heavy rains or more severe weather.

High indoor humidity can also be caused by poor indoor ventilation when taking hot showers and baths and when cooking.

High humidity can cause moisture to be pulled into drywall and insulation and can lead to moisture damage to the studs and framing of your home.

Humidity moisture damage requires professional moisture removal treatment to prevent further damage.

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Water infiltration moisture problems require plumbing or roofing repairs to resolve moisture intrusion, while high humidity within walls requires moisture extraction systems.

Moisture damage can cause a mold growth problem on and within your walls, so you will want to make attempts to dry the damp drywall as soon as possible.

Mold needs moisture and darkness to grow and porous plasterboard is a prime breeding ground for mold.

Excessive dampness and moisture in any part of your home can lead to mold and mildew.

Mold is a common household allergen and can cause mild to serious health problems, especially for those suffering from asthma.

How Does Humidity Damage Insulation?

Mold growth can show up on many different types of building materials, including insulation. If you have a problem with wet insulation, you need to act quickly. How does humidity damage insulation?

High humidity can damage insulation by preventing the insulation from effectively being able to slow the transfer of heat. The wet, porous material is also a ripe breeding ground for mold and mildew, which can easily spread to other building structure areas of your home.

Most of us have had mold and mildew in our homes, as mold is a very common yet annoying part of life.

Mold can damage building materials and cause them to decay and pose a health risk to those living in the contaminated area.

Depending on what type of insulation you have will depend on how your insulation is affected by water damage.

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Fiberglass Insulation

Fiberglass insulation is common and made without any harmful chemicals or materials.

Fiberglass insulation is used around ducts in an HVAC system to help keep conditioned air where it belongs as well as in walls to protect the home from outside temperatures.

What to do if your fiberglass insulation gets wet?

Because fiberglass is made up of small glass strands, it does not absorb water. When moisture fills the gaps between the fibers, however, the insulation’s capacity to inhibit heat transfer is compromised.

Wet fiberglass insulation is about as effective as no insulation at all since water is a conductor.

What to do:

  • Use a dehumidifier or fan close to the wet insulation to help dry out the area.
  • If the water damage is pretty bad, consider removing the batts and laying them out to dry in a warm room.
  • Replacing the insulation may be necessary if you notice a bad odor after the drying process. This can happen when polluted water comes into contact with the insulation.

Foam Insulation

Foam insulation is created when gas bubbles are injected into a liquid which then becomes solid.

This process creates what is known as expandable polyurethane foam, one of the most common types of this insulation.

If the wall and floor cavities are filled with hard white foam, your property has spray foam insulation. 

What to do if your foam insulation gets wet?

Even though spray foam acts as a moisture barrier and forms an airtight seal, the leak is still a concern since water can harm the wood around the insulation.

Try the following to take care of the problem:

  • Locate and seal the hole where the water is coming from.
  • Dry the area with a dehumidifier, a fan, or both to help remove the moisture.

Cellulose Insulation

Cellulose insulation is made from cellulose fibers that are compressed and come in many forms, including cellulose spray foam and cellulose blown-in panels.

Cellulose insulation is ecologically friendly because it does not contain formaldehyde or fiberglass.

If you observe loose gray fibers in the wall and floor cavities, you have cellulose insulation.

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What to do if your cellulose insulation gets wet?

Cellulose is a plant-based product made mostly of recycled newspaper that can be difficult to recover after getting wet.

You might be able to remove the wet cellulose insulation, let it dry for a few days, and then replace it if the area is small enough.

If the leak was more severe, a larger section of the insulation may have been soaked.

Mold can start growing in as little as a few days, necessitating complete removal and replacement.

How Does Humidity Damage Floorboards?

When high humidity levels are present, wood such as floorboards has a high chance of being damaged. How does humidity damage floorboards?

Humidity can damage floorboards by causing warping, buckling, crowning, or cupping. Floorboards absorb the moisture from the air which expands the wood, and when humidity levels decrease, the wood contracts. This fluctuation stresses the floorboards promoting unsightly damage.

If the air in your house has high relative humidity, the wood in your home will absorb excess moisture.

As a result, hardwood floors can swell, which creates pressure between the planks.

When the moisture content in the wood fluctuates between high and low levels, there is a high chance that cracks will appear on the boards.

These cracks can increase if high humidity levels remain for several days or weeks at a time. Wood that is high in moisture content will almost always be soft, and it can even have a spongy texture.

If high humidity levels are going to occur frequently, you should seal the wood.

The best time to protect your floorboards from high humidity is during installation. Wood that has been treated for protection against high humidity will not only last longer but will also require less maintenance.

Sealing the wood is just one method of high-humidity protection that is used by professionals.

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It is also possible to use high-humidity protection products after the installation has occurred.

The most common high-humidity product used by homeowners is high-gloss polyurethane.

This sealant provides high-humidity protection for high-use areas where high humidity is likely to occur.

It can also be used in high-humidity climates. The sealant will not only provide high humidity protection but also makes the floorboards look shiny and new.

How Do You Know If Your House is Too Humid?

There will always be some level of humidity in the air, but how much is too much? How do you know if your house is too humid?

Your house is too humid when you feel the moisture on your skin or steam rising from objects, as well as the condensation on windows or the smell of mold and mildew. The air in the house will feel heavy and wet, and breathing can be a bit uncomfortable due to the narrowing of the airways.

If humidity becomes too high indoors, it can damage objects and make people uncomfortable.

To find out whether indoor humidity levels are too high, take these measures:

1) Check the humidity level in the house by using a hygrometer.    

2) Look for signs of moisture, such as condensation on windows and walls, water spots on the ceiling, and black mold.

3) Inspect items inside your home that can be damaged by high humidity levels.

Signs of too much humidity indoors are warped wood flooring or cabinets, mold or mildew on books and drywall, rusty metal tools, and brittle leather.

Humidity is measured with a meter called a hygrometer. Another way to measure humidity is with a sling psychrometer.

It contains two thermometers: the bulb of one is wrapped in moist cloth; the other has a dry cloth over its bulb. The difference in the readings indicates relative humidity levels.

Relative humidity is a measure of how much water vapor there is compared to the amount that air can hold at that temperature.

When it’s close to 100 percent, then the air is “saturated” and moisture will be released as condensation. That’s why dew forms on grass and other surfaces at that temperature. 

Related Article: If you feel you have high humidity in your home, testing your humidity levels in your home is recommended. Where to Place a Hygrometer in a House?

Ventilating a home is very important, especially when cooking and bathing. Opening windows or turning on ventilation fans will help keep the humidity levels down.

Trina Greenfield, Author
SmackDown Media LLC

About the Author:
Trina Greenfield, the owner of SmackDown Media LLC, is passionate about providing information to those interested in the air quality in and around their homes. Trina writes content about things she’s passionate about, such as safe, in-home air, educational platforms for children and adults, as well as all things family-related.