Problems and Solutions: Frequently Asked Questions

FAQ About Sealing and Insulating Your Crawl Space with STS

I rarely get water in my crawl, but I get spiders, silver fish and other insects coming up into my house. What should I do?

Installing the STS Liner System will seal your crawl space. Insects and other pests can not eat through the liner, making it harder for them to find there way into your home. The other added benefit, is that, you now have a clean, dry, new found useable storage area in your home.

I have a dirt crawl space and when there is a heavy rain, I get standing water in my crawl space. What should I do?

If you do not have a sump pit and pump, you need to install one with drain tile. Then install the STS Drain Fabric prior to installing the STS Liner System, this will allow water trapped under the liner to travel to the sump pit, preventing any more water problems.

I want to install your liner system in my crawl space, but there are some cracks in my foundation walls. Should I have them fixed first?

Yes. It is always a good idea to seal up cracks and preventing them from getting worse, but it is not mandatory! With our concrete crack injection kits, it is a simple process to repair cracks. But, if you decide not to fix the cracks and still install the STS Liner System, the liner will allow any water seepage to run down the wall and drain harmlessly into the soil under the liner or travel to the sump pit.

I have just recently received a quote for finishing my crawl space with concrete. It was a little pricey, but they told me that this would solve my problems of any future water problems. Is this true?

No. Concrete when pumped into your home will create an over abundance of moisture in your crawl space and inside your home until the concrete fully cures. Moisture is what you are trying to keep out. Concrete over time cracks and allows moisture seepage, as well as, forming a chalky surface which increase the dust and allergens in your home . The STS Liner System will not crack or create dust, keeping your home dry and healthy!

I just bought an old house that has block walls for the foundation and there is signs of water problems in the past. What should I do to prevent future problems?

Installing the STS Liner System will prevent future water problems, but before you install the liner, you should drill holes (through 1 side) in each block at the bottom of your foundation at least a 3/4” (drill bit is included in kit to install anchoring pins) to allow any water that may be trapped in the blocks to drain out under the liner and drain harmlessly into the soil or travel to the sump pit.

I installed a new sump pump because my old pump went out. All of the water is gone now, but I still get a musty smell when I open the door to the crawl space. What can I do?

Odors and gases coming up from your crawl space will reduce the over all air quality in your home., causing possible allergies and respiratory problems. Installing the STS Liner System will seal out all odors and gases from coming up through the soil and into your home, improving the indoor air quality of your home and creating a healthier living environment for you and your family.

Once I install the STS Liner System, should I close the air vents in my crawl space?

It all depends on if you have any gas fired appliances ( hot water heater, like I have in my house, furnace, etc…) that draws air for combustion from the crawl space! If this is the case, NO, you can not close the fresh air vents. Closing the vents if you have a gas fired appliance could create a dangerous carbon monoxide problem in your home. If you are not sure if you should close the vents, contact a local licensed HVAC contractor and ask for them to check out your crawl space for any air draw issues. If there is no items drawing air for combustion or other needs, Yes, by all means, close the air vents. This will stop moisture, insects and cold air from entering your crawl space.

What is the best way to close crawl space air vents?

Closing the air vents should be done from the inside by cutting a piece of the STS Liner to the size of the vent, then applying STS Super Bond to the inside of the air vent louver, covering all for side and the middle, place the pre-cut piece of liner up to the vent, foil side facing out, pressing liner into the Super Bond adhesive. This is the best way to seal your vent, but in the event you were to ever need the vents, all you would have to do is remove the liner from the vents.

I read on your site that your liner could be used to help keep my floors warmer. Shouldn’t I just insulate my floor joists with a fiberglass insulation?

No. Fiberglass insulation is a breeding place for mold and mildew. It traps moisture causing the wood to stay damp and start decaying over time as well as it does not reflect the radiant heat. To reflect radiant heat there must be an air space. Using the STS Liner as a Heat Shield, place the liner with the foil side facing up towards the bottom of your floor, staple the liner to the bottom of your floor joists. This will create an air space between the bottom of the floor joist and the floor. The air space in between will allow the heat that radiates through the floor to reflect off the foil side of the liner and back up into the floor.


After installing the STS Liner System I noticed a couple of days later that the liner looked like it had a big air pocket in it. When I called STS they told me that I most probably had Radon Gas getting trapped under the liner and that I should get it tested right away. Then I asked what should I do if it is Radon Gas?

The first thing that needed to be done was confirm it was Radon Gas being trapped under the liner. After confirming it was Radon Gas, the next step was to install a vent pipe from under the liner to the outside, allowing the Radon Gas to escape harmlessly into the air outside the home. This is just one reason why it is necessary to install a Zero Perm Liner System. A Zero Perm Liner allows Zero Moisture, Zero Gasses and Zero Odors to pass through and enter the home. If Radon Gas, moisture and odors are allowed to enter the home, not only will they effect the quality of the air and the health of everyone in the home.

Crawl Space Encapsulation|Crawl Space Vapor Barrier|Crawl Space Insulation