If you are struggling to tolerate the offgassing of a new house after using the strategies in the article on how to bring down new house offgassing you can create a sealed off “safe room”.
This is often done for folks who have extreme environmental sensitivities.
There are a few ways to make a safe room in a house. You can use something impermeable to seal off the walls, use positive pressure to push contaminates out, or replace all the materials in that room.
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1. Using an Impermeable Barrier on the Wall
These materials block VOCs.
Heavy-duty aluminum foil is much easier to work with than the thinner type used in cooking and grilling.
You may need several layers to totally block smells, though for most people one layer will suffice.
Attaching the foil with tape
The most obvious and temporary way to attach the foil is with tape. Though tape does offgas.
You want to use green painting tape for this as it will not damage the walls and is easy to remove – a healthy person could rip off/take down the whole room in probably 20-30 min.
The blue tape is more toxic so I wouldn’t use that. You could use aluminum tape but it is very sticky and will leave a residue and will be hard to take off.
Aluminum tape also smells much more than green tape, though the aluminum blocks most of the smell, the smell/VOCs do come in through the edges.
Another very tolerable tape which claims 0 VOC, but still smells a little like glue is SIGA Rissan. That is the most tolerable tape that is going to hold up, in my assessment.
Don’t underestimate the smell of the tape when you have a whole room full of it. I can tolerate any tape in small amounts sniffing it right to my nose. I am unable to tolerate any tape when there is a whole room full of it. The larger the sheets of foil the less tape you will have.
Attaching the foil with an all-natural glue
I have also used the all-natural gum arabic to make a totally benign glue. As long as this can dry to the inside of the wall from the interior that will be fine to use. Do a test piece, let it dry, remove it and see how easy it is to remove the gum arabic paste.
I would not use foil on the walls where you have colder air inside than outside (AC use), though it does depend on your outside humidity and dew point. This can create condensation and mold behind the foil.
If you have central HVAC you won’t be able to isolate this room properly. You can in most instances block up one or more vents, but this can also cause trouble to the whole HVAC system.
Note: You can use foil on isolated areas to block offgassing. I have used this successfully on smaller areas that were offgassing like a new door.
Other materials to block offgassing
You can also use glass panels, aluminum sheets or tile on the walls.
2. Using Positive Pressure to “Push Out” VOCs, Fragrance and more
Positive pressure means you are bringing in more outdoor (or filtered) air than you are exhausting from the room.
Some people tile a room or put aluminum walls or glass up as a more permanent version of foiling walls. (You have the same risks with interior vapor barriers when doing this).
While this can be quite effective in pushing offgassing out of that room it comes with risks of condensation as mentioned in the above section. It should not be used with it’s warmer inside than outside (generally), you can push warm air toward the cold exterior layers and cause condensation and mold.
If it’s hot and humid outside you would be bringing in hot humid air, which could also be a problem.
Strategies to make positive pressure successful
The simplest way to create positive pressure is with the IQ Air. On the accessories page scroll down to Health Pro Plus and you will see the InFlow W125.
As pictured left, this draws air in from outside and then through the air purifier and into your room, bringing you outdoor air that is filtered and creating positive pressure.
As long as you have adequate isolation from the rest of the house creating one safe room that has positive pressure can work well.
Keep in mind, mold VOCs (mVOCS) come through the air and cross-contaminate much easier than VOCs. This strategy is for chemical VOCs from building materials (or to keep out a neighbor’s contaminants).
This should not be attempted in a significantly moldy house. I can smell and react mold off most houses up to 100-200 ft away.
3. Types of Safe Rooms
The first way to create a safe room is to put foil up on the walls like in the first section. These are some other ways to build out that safe room.
A. Build out the room with new materials
B. Room within a room
Things are simplified if you have positive pressure within your room within a room.
I have created a smaller room with sheets of rigid foam. You can also use polyethylene plastic, house wrap like Tyvek, foil/radian barrier, a glass greenhouse, acrylic panels, a large canvas tent or any other air barrier. Basically, create a giant tent within the room.
Having a room within a room simplifies problems you could cause by creating an interior vapor barrier (humidity, condensation in walls) as well as pushing air into walls with positive pressure.
You want the room to be big enough to be able to put in a dehumidifier if needed and a heater.
In this scenario, you bring in that outdoor air into your inner tent and you would open a window in the main room to equalize pressure.
C. Double room for extreme containment
If you need to go to extremes to control for cross-contamination you need an entrance room to your safe room.
Use zipper doors to create a vestibule.
When using a double room system, pressurize the main room at 2 pascals for pressure – as recommended by Carl Grimes.
When using the entrance room, pressurize that with the air from the main room to control contamination from the main house.
The air that you are bringing in needs to be clean.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.