Can air pass through drywall?

Author: Richmond Koch  |  Last update: Sunday, August 3, 2025

Gypsum board drywall is, itself, a suitable air barrier material. The taping of drywall seams results in a plane of airtightness at the field of the wall. However, several steps must be taken to use this material property to create a continuous and complete air barrier system.

Can air pass through walls?

Even the wind load of strong storms cannot transport air through an intact outer wall - on the contrary: masonry and plastered walls are just as airtight as concrete or professionally finished prefabricated walls.

Does drywall count as a vapor barrier?

Class III vapor retarders are identified by the IRC as latex or enamel paint. However, research shows that standard painted drywall is commonly vapor permeable (greater than 10 perms, up to 40 perms) – a benefit during the cooling season, but a potential concern during the heating season.

Can humidity pass through drywall?

The humidity levels can also affect the finish of the sheetrock. When the air is moist, it can cause the paint or wallpaper to bubble, peel, or become discolored. The moisture can sometimes seep through the sheetrock and damage the insulation or framing behind the walls.

What is the air permeability of drywall?

The permeance of unpainted drywall is very high, generally between 20 and 90, so it's not a vapor retarder at all. Meanwhile, air leakage through a 1 square inch hole in a sheet of drywall allows 30 quarts of water vapor to pass through the drywall under the same conditions.

Airtight Drywall

Can air go through drywall?

Gypsum board drywall is, itself, a suitable air barrier material. The taping of drywall seams results in a plane of airtightness at the field of the wall. However, several steps must be taken to use this material property to create a continuous and complete air barrier system.

Is drywall breathable?

For all intents and purposes air will not flow through it if installed correctly, however the importance of being air tight is to control moisture and condensation from forming inside of your walls.

How do you know if moisture is behind drywall?

Moisture and water that get behind the wall cause the backside of the drywall to soften and even become mushy. Look for soft spots or wet spots in the drywall and gently press into them. If the drywall depresses, there is most likely water damage. Mold on your walls' surfaces.

How do you stop moisture from coming through walls?

Preventing Damp Walls
  1. Condensation – ensure good ventilation and minimise creating moisture internally.
  2. Good outdoor maintenance to your property.
  3. Monitor external vegetation to reduce the risk of it damaging masonry and render.
  4. Don't plant large plants near your house as roots may damage foundations or damp proof courses.

Can mold grow through drywall?

If you find mold on your drywall, you'll most likely need to get it replaced. Mold on drywall can indicate a deeper problem in the stud space behind your wall since it can penetrate the surface. In this case, you'll need to cut it out and replace the drywall in the affected and surrounding areas.

Should you put plastic under drywall?

Yes, covering your insulation with a vapor barrier plastic before installing drywall is crucial. It prevents moisture buildup that can lead to mold, rot, and even structural damage. A polyethylene vapor barrier also adds a layer of fire protection, making your home safer.

Does heat pass through drywall?

Materials that offer better thermal resistance are naturally better insulators than those with lower thermal resistance. Frankly, while drywall is a wonderful material for many reasons, it isn't much of an insulator.

What is the difference between air and vapor barrier?

Quite simply an air barrier reduces the flow of air, a vapor barrier reduces the flow of water vapor and a water resistive barrier reduces the flow of liquid water. Each function is completely different.

Does drywall act as a vapor barrier?

To explain this further, Gypsum board (drywall) is vapor permeable, but stops air flow. This means water vapor can diffuse through it, but air cannot pass through it.

Can moisture travel through walls?

Of the several mechanisms that can cause wetting of a wall, it is generally acknowledged that the direct movement of warm, moist air from the interior of a house through the wall cavity is one of the most important.

Does air pass through plywood?

In a related project, NRC measured the air permeance values for North American plywood and OSB and found both to be “very air-tight materials.” Specifically, the six plywood products with thicknesses from 3/8 inch to 1/2 inch had air permeance between 0.00013 and 0.010 L/(s.

What draws moisture out of walls?

Use fans to move air around the damp walls. Also use dehumidifiers, which can help remove moisture from the air and walls. Professionals use tools like moisture meters, infrared imaging devices, dehumidifiers and heavy-duty fans. That ensures the walls are truly dry before further repair, painting or refinishing.

What can I put on walls to stop damp from coming through?

You'll need to use a dedicated mould remover in order to kill any patches of mould on your walls. You can then use paint to stop damp coming through your walls. In fact, damp proof paint is a great option for any home that is prone to damp.

Will a dehumidifier draw moisture out of walls?

Dehumidifiers can indeed aid in drying wet walls. After a flood, leak, or a spell of extreme humidity, damp walls can develop. A dehumidifier removes extra moisture from the air, lowers the humidity, and stimulates evaporation.

How to tell if mold is behind drywall?

Musty Smell

If you think there's mold in your walls, get on your hands and knees and smell the electrical outlets. This might sound silly, but it may help you sense mold if it's growing within walls. Outlets have better access to the area behind the walls. Thus, smelling them can help identify the mold problem.

How do you fix moisture behind drywall?

Dry the water damaged walls

Use high-efficiency blowers and dehumidifiers and open the windows and doors. Use fans to increase air flow behind walls and leave them running for at least two days so the studs and flooring can completely dry.

Is there an app to detect moisture in walls?

The moisture mapping app records wall and concrete floor moisture reading details in all areas, making it easy for users to get the details they need quickly and easily from any mobile device.

Can air travel through drywall?

Air can get through where the drywall meets the bottom plate. Since air can get under the drywall.

What are the side effects of breathing in drywall?

Over time, breathing the dust from drywall joint compounds may cause persistent throat and airway irritation, coughing, phlegm production, and breathing difficulties similar to asthma. Smokers or workers with sinus or respiratory conditions may risk even worse health problems.

Can moisture go through drywall?

Drywall's Vulnerability: Moisture

While it is relatively resilient, it is not impervious to water damage. Exposure to water can compromise its integrity over time and cause drywall damage.

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