If you are struggling to tolerate the off-gassing of a new house after using the strategies in the article on how to bring down new house off-gassing 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.
The detailed Safe Room Series:
- Using positive pressure to push out VOCs
- Using air exchange to dilute VOCs
- Creating a room within a room
- Sealing up a room
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1. Using an Impermeable Barrier on the Wall
Aluminum foil
To create a non-toxic room in your home you can use heavy-duty aluminum foil, or other barriers on the walls/ceiling/floor.
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 off-gas.
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 smellier 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 was 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.
Drawbacks
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 off-gassing. I have used this successfully on smaller areas that were off-gassing like a new door.
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.
This is done with a fan specific types of fans, ERVs, or special attachments on air purifiers which I explain and link to on Substack.
While this can be quite effective in pushing off-gassing out of that room it comes with risks of condensation in some climates.
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
Other limitations
This strategy is for chemical VOCs from building materials (or to keep out a neighbor’s contaminants).
I can’t say that I recommend it in a significantly moldy house.
3. Using Targeted Intense Air Exchange
Another strategy is to use point-of-use air exchange in one room to overturn a tonne of air in that one room.
In this strategy we also need to mediate the temperature and humidity of the incoming air so that the room is still liveable.
I reviewed all the smallest air exchangers here that you can install in a single room without breaking walls.
4. 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
You can redo one room with all safe materials.
Going as far back as redoing the drywall, insulation, and floors. Using all safe materials.
This is a upcoming article in Substack.
B. Room within a room
In this strategy we are creating a smaller, usually more temporary room within your regular room.
We then add positive pressure within your room within a room to isolate that from the bigger room.
Having a room within a room can simplify the problem you could cause by creating an interior vapor barrier (humidity, condensation in walls) as well as pushing air into walls with positive pressure.
You may need to add a dehumidifier, heater or AC in this scenario.
This strategy is outlined on Substack.
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.
This is shown in Substack as well.
Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.
Join the top Substack on healing from MCS and mold!
Kb
Is there any issue with creating positive pressure when it’s hot or cold out?
Corinne Segura, Building Biologist
yes, mentioned in the article
R. Baffo
Please help with a very stressful, complicated, and confusing situation. I am a senior with severe respiratory illness with critical decisions to make about resolving contaminated (odorous) bedroom air–and I am not a chemist. The bedroom was slated to be used by me and a person who is immunocompromised; it was previously used by me but had to be vacated after the contamination (about 9 months ago). Based on my understanding of in-depth research and consultations, the odor of the room was produced from reactions between the ozone in an ozone generator (OG) and items and materials / compounds in the room. Backstory: In late April, 2025, a window vendor replaced a window in the bedroom and used an unknown, strongly toxic-smelling agent (supposed by the landlord to be window cleaner, but it was very intense). The ozone OG was supposed to get rid of the window-related odor. The OG was used for about a week as it did not remove the initial window-related odor – actually, instead, window odor appeared to morph into a different odor. The morphed odor, which has persisted, can be described either as a pool or chlorine smell or even a sweet smell (kind of like an old tavern). This description occurred repeatedly in my research, identified as that from an OG. This odor has persisted even with almost constant ventilation over 7-8 months. Then we tried “EXPEDITED OFF GASSING / BAKING ” – as recommended by an environmental hygienist: heat the room to 80, let sit for an hour or more, then turn off heat, open window / place fan in window, blowing outward. As recommended by many environment-friendly sources, we’ve tried removing potential reactants to the ozone in the OG – basically everything in the room. The carpet was removed later in the game, on 12-23-25. Though we didn’t sniff the carpet, other items we sniffed, including mattresses, mattress pads, and clothing all emitted the same odor as described (some more than others). The only things left in the room are a baseboard heater and blinds. The baseboard heater sits directly below the window that was replaced (please recall, it was odor discovered after this replacement that led to the use of the ozone generator). As the odor still persists all these months later,
1) Would you recommend removing / replacing the baseboard heater and the blinds (the only items left in the room). I noticed that, when I used a space heater in the room instead of the baseboard heater, I detected an odor different from what I described.
2) I wasn’t quite clear on your method of baking …please see my description of “EXPEDITED OFFGASSING* above. Could you please explain your off-gassing method in different words?
3) Would you please explain how / where exactly to position the fans for ventilation? Would this be the same as creating positive pressure? For general ventilation, Would I put one fan in the window to vent outside and another in the window facing inside? Or one in the window, one in the room? Btw, kept the door to the room closed for 9 months.
4) Painting has been recommended as a way to trap the off-gassing OG VOCs producing the pool odor. An environmental hygienist consulted recommended oil paint, but it is high VOC and otherwise not feasible (for me, at least). However, he also said latex paint might work – maybe just not as well as oil. As a result, I am considering using ECOS Air purifying paint as it is formulated with zeolite, which the company states capture VOCs such as formaldehyde (a known secondary pollutant from OG ozone reactions). Does this sound like a viable option?
Andrew Greenhut
I have two things to add:
(1) If you want to use Aluminum tape (very useful to have on hand), a tip is to buy it before you need it and leave it outside for a month or two out of the sunlight. It will naturally offgas most of the glue smell so that when you use it you don’t have to worry as much.
(2) I buy activated-carbon filters and add them to the intake of box fans, air conditioner filters, and car cabin filters. They soak up VOCs for a while, and when they start wearing down you can just replace them. It is relatively cheaper to add the carbon layer to air filters than to buy expensive high-end ones, and you can replace the carbon more often. https://www.amazon.com/dp/B0835QCV9L?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Sarah
Corrine, I have a few questions on this topic as I’m going to need to have containment put together in my home soon.
Plastic: A contractor needs to build containment out from some large, tall windows where we anticipate potential issues (water intrusion and all that can go along with it) when the old windows are removed. No evidence of water on the interior of the home, but a cursory investigation by the window installers on the exterior revealed water intrusion so they sealed it back up and off we go trying to figure out the next steps…. Although I usually use the shower curtain approach as described in a prior comment, it may not be feasible for this because they’re slightly thinner than the minimum mils for this kind of job and are not something the contractor’s team is used to working with. Do you know of any containment product that might not stink has horribly as the traditional plastic that’s used? I cannot tolerate the smell of it. It makes me ill.
Tape: Since the containment will be really tall, will be on three sides due to having an open floor plan and few walls to attach things to, and there’s weight to consider, I doubt green tape will support the weight. Is the SIGA tape stronger? And, although I realize this is subjective, so you think it smells more or smells less than the green tape (as a point of reference)?
Corinne Segura, Building Biologist
SIGA tape is strong and the best i found when i was super sensitive but other tapes from 475 might also be good or even better.
Tyvek house wrap is another option.
Sarah
Thanks, Corrine. I was wondering about Tyvek and started some cursory reading. It seems like it “breathes” and wonder if that’s a deal breaker if used for containment where there could be mold. (Don’t know what we’ll find when the old windows get pulled.) Also not sure if it’s at least 6 mils. Do you know? Also, what’s your opinion on odor compared to traditional plastic sheeting used for containment? Meanwhile, gonna buy a roll of that tape and see what I think. If it’s strong and not stinky that will be a great find!
Corinne Segura, Building Biologist
it blocks all spores
Sarah
Thank you!
Sarah
This isn’t exactly related to a safe room, but it seemed the closest subject to drop this tip that has to do with the challenge of containment during remodeling or remediation. Usually, plastic is put up using blue tape. Ick. And ugh. Here are a few alternative materials I’ve used that helped quite a bit. Instead of the typical plastic that’s used, I buy several PEVA or EVA shower curtains. (Most are 72×72, but you can find some on Amazon that are extra long, as in 180″.) There is hardly any odor, though I still take them out of the package and let them off gas a bit before I need to use them. Instead of blue tape I used green tape, however that isn’t as strong as the blue. If it’s not sufficient to support the size area you need, supplement with Zip Wall kits. These will allow you to support the shower curtains in position enough such that the green tape will work well in conjunction. This system has saved me a lot of grief over the years and thought I’d share should anyone else benefit from it.
Corinne Segura, Building Biologist
thanks for the tip. another tape option that is good is Rissan
Sarah
Thank you. I’m going to order a roll this week-end and try it out. Containment is always a huge challenge and the more elements that can be neutralized, the better!
Telkom University
Are there any successful case studies or examples of existing “Safe Rooms” for individuals with severe environmental sensitivities that can serve as models for future designs?
Corinne Segura
On EI Wellspring