10 Ways to Prevent Moisture (1)


Most vault rooms are located in the basement of a home. Unlike a closet-turned-safe room in the dryer parts of your home or business, moisture is always a concern in a basement. Controlling moisture in a vault room is crucial in preventing damage from mold, mildew, and corrosion. Moisture is a silent intruder and can cause thousands of dollars in damage without you knowing. And lets be honest, do you really want to invest your hard earned money on a premium product like our Titan Vault Door, only to have everything behind it ruined? But how can you protect your vault room from moisture?

Top 10 Ways To Prevent Moisture Problems In A Vault Room:

  1. Consider the Basement Walls
  2. Proper Sealing and Moisture Barriers
  3. Drainage and Grade
  4. Dehumidification
  5. Proper Ventilation
  6. Temperature Control
  7. Moisture Absorbing Materials
  8. Water Leak Detection
  9. Proper Storage
  10. Regular Maintenance
  11. Conclusion

Consider The Basement Walls

One major thing to consider is what type of walls will be used in your vault room. The 3 most common types of foundation wall are:

  • Concrete Masonry Unit (CMU) blocks can be a cost effective and attractive basement wall option. However, CMU blocks are more porous than poured concrete. According to the ASHRAE handbook, CMU blocks typically have a permanence (moisture permeability/thickness) of around 2.6 perms (higher is more porous). A poured concrete wall 8 to 10 inches thick has an 80% lower perm rating at 0.3-0.4. Any perm number from 1-10 is considered semi-permeable. One way to improve the perm rating of a CMU wall is to slurry the hollow parts of the CMU with concrete, which might improve the perm rating by 50%. Another problem with CMU block is that it has many seams which make it harder to seal against moisture. 

  • Poured concrete is a common wall option. An 8 or 10 inch poured concrete wall will let through 80% less water than a CMU black wall, at 0.3-0.4 perms. Also, poured concrete is a solid surface with few cracks, making it easier to seal.

  • Insulated Concrete Form (ICF) walls use polystyrene foam panels to form a casing around a concrete poured wall. ICF walls tend to be stronger than standard poured concrete walls and are more resistant to cracking. That resistance to cracking makes it better suited to keep moisture out than a standard poured concrete wall.

Proper Sealing And Moisture Barriers

Sealing the exterior surface of the basement wall is the first step in controlling moisture in your safe room. Before your foundation is poured, have a plan to seal the exterior surface. Regardless of the wall type, adding an exterior layer of waterproofing is critical for long term moisture protection. There are 3 main ways add an exterior moisture barrier:

  • Waterproofing Paint or Sealers: Commonly used and available, water proof paints and sealers can be applied directly to the surface of the basement wall. When correctly applied, these products protect the concrete from external water intrusion but still let the concrete breath. Allowing the concrete to breath prevents moisture build up inside the concrete. These products can last 10 years or more when a high quality product is applied on a clean well prepared surface.

  • Waterproof Membranes: These membranes come in sheets or rolls and can create a watertight seal on concrete or block surfaces. The membranes are typically made of rubberized asphalt or modified bitumen. They can be more difficult to apply than paint or sealer but are thicker and more resistant to damage.

  • Cementitious Waterproof Coating: These coatings are cement based and are applied directly to the concrete surface. A waterproof barrier is formed when the coating chemically reacts with the concrete. This type of coating can withstand greater hydrostatic pressure and is suitable for areas with high water tables. One drawback is that this type of sealer is less flexible and can crack if expansion and contraction of the basement is too large.

Once the exterior walls are waterproof, the next step is to check the ceiling and interior walls for intrusion points. Take time to look for cracks or gaps in walls, floors, ceilings, and seal them with the appropriate material.

Drainage And Grade

Every building should have a drainage plan and grade layout. Most contractors are very familiar with the drainage and grade needed for homes built in their region. However, if you’re installing a vault room it’s good to keep a few things in mind.

  • Make sure the basement has adequate drainage to keep exterior water from the basement naturally.

  • Make sure your vault room isn’t located in a low spot in your basement. The safe room should be the last area that should see water if the basement floods. Ideally the vault room has the highest elevation in the basement.

  • Consider building your vault room floor higher than the basement floor. If the basement floods that will make the safe room the last part to see water. Also consider the grade inside the vault room. Make sure any excess water drains into the basement and doesn’t get stuck in the room.

  • Consider installing a drain in your vault room - but be careful. A drain in the vault room is a logical way to reduce the risk of flooding but water can back up in the drain line and still flood the room. If you decide to add a drain line, consider putting in a one-way valve to prevent the drain from back feeding.


After choosing the correct sealing and drainage, the next step is to consider adding a way to dehumidify your vault room. Even with the best sealing and drainage, basement air is typically high in moisture. The simplest way to dehumidify is to add a dehumidifier. These units are common at large retailers and provide a simple and effective way to keep air moisture under control. A dehumidifier located anywhere in the basement will keep any air entering the vault room under control. However, if you have items that are more sensitive to moisture or your basement walls tend to allow more moisture in, you might consider putting a dehumidifier in your vault room. In either case, you will need to consider a few things:

  • Make sure you have a plan to empty the dehumidifier water trap periodically or pipe the dehumidifier to a drain.

  • Verify that the dehumidifier you select is big enough for the space you’re trying to control. A whole basement will take a larger unit than just the vault room.

  • Plan ahead to have power outlets near the area that you plan on setting the dehumidifier

Proper Ventilation

Good ventilation can go a long way in preventing moisture issues. Stagnant air tends to be damp. Mixing fresh air will prevent high humidity pockets. First, ensure you have good ventilation inside your vault room. This can be as simple as running a fan occasionally. Next, make sure fresh air is occasionally added to the vault room. This may happen naturally if you enter your safe room daily or even weekly. But if you sometimes go weeks without opening your vault door, you might consider leaving it open once a week to mix in fresh air. Another option is to add a vent from your home's existing HVAC system to circulate air into and out of the vault room. If you decide to plumb in HVAC venting, be sure to attach the vents properly to keep any flames out of the vault room in case of a fire.

Temperature Control

Controlling the temperature of a vault room provides stability and prevents condensation from large swings in temperature. There are several ways to control the temperature in your vault room.

  • Connect your whole home HVAC system to the vault room: This is a cost effective and easy option. Make sure your contractor knows to pour the openings in place for the vents. The main drawback is that this could expose the safe room to a fire risk if the vents aren’t correctly attached or if smoke back feeds in the HVAC vents.

  • Put a small source of heat in your vault room: The idea here is that the heat will keep the vault room warmer than the rest of the house and significantly reduce the risk of condensation inside the vault room. This could be as simple as an incandescent light or even a small space heater. There are several drawbacks to this though. First, any heat source could become a fire risk. Even an incandescent bulb can get hot enough to light paper on fire. A newer LED would never do that. Second, it requires a planned electrical outlet dedicated to running something everyday, all day.

Install a dedicated HVAC system for your vault room: This option is the most expensive but the most robust. A thermostat and humidistat inside the vault room would keep the temperature and humidity exactly where you want them, unlike a whole home unit. Also, if the register unit is installed inside the vault room, like a mini-split system, the risk of external fire is much less. The main drawbacks include upfront cost, operating cost, and maintenance costs.

Moisture Absorbing Materials

Desiccant packs and moisture absorbing materials are another option for moisture control in a vault room. A smaller vault room may only need these materials to protect against moisture. Another option is to use moisture absorbing materials for smaller enclosed areas inside the vault room, like a safe or closet. These materials have drawbacks though. For medium to large vault rooms, these materials aren’t enough to control moisture. Another issue is that they can only absorb a fixed amount of water and need to be replaced periodically, adding cost and maintenance.

Water Leak Detection

Even the best construction for your basement and vault room can’t stop bad luck. It’s always best to have a back up plan. Installing a water leak detection system is a great way to add another layer of protection. For under $30, a simple water leak detection system can sound a loud alarm when water is sensed. The simple units are battery operated and can be placed on the floor inside or right outside of your vault room. Some units can even tie in with your smart home or security system to give you an alert if you’re not at home. Other high end units can detect the flow of your plumbing system and alert you if there is a leak in your plumbing, and shut off your water automatically. A simple and effective monitoring system can prevent thousands of dollars in damage. Another simple addition is to add a battery backup system to your sump pump. If the power ever goes out during a heavy rain storm, the battery system can keep the sump pump running for hours or even days.

Proper Storage

Another way to prevent water damage is to review how the items in your vault room will be stored. A few simple rules:

  • Don’t store anything that can be damaged by water on the floor.

  • Try to use waterproof storage, like plastic tubs, whenever possible.

  • Consider making any displays or shelving at least one foot off the ground.

  • Store very fragile items in a waterproof container designed specifically to block all water intrusion. These will have seals and latches for positive closing. This type of storage is recommended for any critical paperwork or digital storage like external hard drives and USB sticks.

Regular Maintenance

Every home requires regular maintenance to keep operating. One of the best ways to prevent water issues in your vault room is to keep up on maintenance. Here are a few of the maintenance items that can directly affect your vault room:

  • Check sump pump and drain outlets annually or quarterly

  • Keep eaves and downspouts clean and running. Any water not drained properly may end up in the basement

  • Inspect the basement area for small leaks. These can show up as puddles or just small discoloration in the basement ceiling or walls.

  • Make sure any humidifiers are tested and cleaned annually

  • Have an HVAC expert inspect your AC and heating units annually 


Building a vault room can be an exciting and sometimes overwhelming experience. A little planning can go a long way to make sure your safe room is protected from moisture and humidity. Go through each point above and make sure your vault room is protected!

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Since 1982, Smith Security Safes has been proudly making top-notch vault doors and safe room doors in the USA. Our doors are not just about locks and steel; they are about trust, quality, and peace of mind.

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