Hi guys, new poster here and need some help

About 9 months ago we bought a ICF home from a builder. The home is 2-story with a spray foamed attic and sits over a crawl space that is semi sealed.

He basically layed down clear plastic that was not taped, there is a small hvac supply on one end and a mechanical "relief vent" on the other end. This opens everytime the 1st-floor hvac calls for service or you run the fan. This vents to the outside. 

He also had to cover the EPS foam with sheetrock "code i assume".

Sometime during construction he had a mold problem, the week before we had the home inspected he had a mold company come out and spray some green chemical everywhere . They also removed about a foot of sheetrock all the way around the perimeter of the crawl because of mold. So we buy the home and i proceed to try and fix things.....


I have bought the nice thick floor liner to seal the floor of the crawl. I have mechnicaly fastened the liner to the EPS foam with screws and washers in places. The problem is i need an adhesive to completly seal the liner to the EPS??  What can be bought or what other way can i do this?

I had thought about putting the sheetrock back up around the edge and then sealing the liner to the sheetrock, but this would expose and seal off a portion of the sheetrock under the liner........ i will try and post pics soon showing what the crawl looks like

What adhesive can i use that will work, i have hot melt glue at work, but i doudt the liner would adhere. We cant use petro based products because of the EPS foam, i do have liquid latex, might work?

Can put PlasterMax over the sheetrock, see at www.barrett-inc.com/plastermax/html.  no mold issues with that.  A lot of people use the Barrier under the crawlspace. It has taped sides and can be put in direct contact with the ground or secure it to the underside of floor joists.  Just roll it out, taped edges together.  Good luck

But the problem would still remain... i still have to seal the floorliner,Barrier to the Eps foam? Maybe the floorliner tape would work? I know it will stick to the floorliner and should stick to the foam... not sure if the adhesive is petro based though....

This might work as well.. Eternabond... they use this stuff on rvs for waterproofing the roofs... I just thought of this stuff.... kinda expensive but once attached it aint coming off and will last forever

http://www.eternabond.com/WebSeal-p/cr-wb.htm

the adhesive is made up of Polyolefin and Synthetic Elastomer , would this work with EPS?

I have 2 suggestions for you.  

Check out a product called Permalon  While there is a special tape to seal the seams (fairly pricey), I have used red "Tuck Tape" (I think it is called Duck Tape) in US.  I expect 2 sided 1/16" glazing tape or acoustical sealant  would also be an effective seal between pieces of plastic.

As to how to seal this product to the wall, I have used 1x2's and sandwiched this material between the wood and the ICF every 16".  If this wasn't a retro fix, I would think that a PL series panel adhesive would seal it as well.

I know it isn't a 100% seal but I would expect it is above 90%.   Do you have a sandy soil, or high humidity in your crawlspace?  The green stuff in your photos could be an anti-rot compound as used in PWF lumber.  Photo 1 shows it sprayed on parts of the floor joists, while spots are still "raw".

I would think that with heat in the crawlspace, you shouldn't need exterior ventilation unless it is for combustion air.

I already have the tape to seal the seams of the floorliner for the seams. I also already have the floorliner "white" in the pictures, the lighter clear in the picture is the builder stuff, the white stuff is 12mil.


 The liner tape i have might  work on the "liner - wall"  attachment . I have a whole house  dehumidifier in there now, it still needs a good cleaning  down there, as you can tell in the pics the builder wrap is not taped, etc..... I have the PL stuff for the liner to the concrete, but you cant use that on the EPS if it is Petrol based.

The builder brought in  finely  screened soil , i think there was water trapped in the crawl when he was trying to sell and had the power off for months. Or more than likely he had moisture issues from the soil. Like i mentioned before , the vapor barrier he had down was not sealed or taped.... and the vent only opens and the supply only runs with the hvac... so it want take long in the summer time here with a sealed up crawl.....  I have not noticed any water anywhere since we have been here so far. And i have a humidity sensor located in there now that sends a signal to my base unit. For the last month or so it has been 40-45% , this past summer the dehumidifier would run to keep it at 50% off and on through out the day

 

To be honest, we should have investigated the crawl space issues more and the way it functions. But everything was kinda rushed, inspection..closing... assurance from everybody....etc.... We supposdly have a 1 year builder warranty in NC, but that is only as good as the builder..etc...

Simple solution: take a piece of the liner tape and stick it to the eps. give it a few days and take off. If it is going to react with the eps, you should see the beginnings of the reaction within 48-72 hours.
Is there any type of drainage system in place in the crawl? If not, install one before finishing your sealing. The ground water that comes up into the crawl needs a way out, otherwise, your plastic will be floating on a very shallow indoor swimming pool.

In the year we have been here i have not noticed any water at all. I go down there atleast 4 times a week. What type of reaction between the liner tape and eps would be seen? I know there is a perimeter drainage system, he had access ports throughout the property with tile ... will have to do some digging in the crawl to make sure, but i am sure he did.

Notthing dangerous. The reaction would be a slight deformation of the eps. Melting, if you will.

Is there any ventilation in your crawl space? you may want to install a vent fan on a humidistat control so you can set your humidity at 50% or lower. And if you have an evr or a air to air exchange (which you should and if you dont you should look at getting one.) you should tie it in to your crawl space.

I have a ultraire whole house dehumidifier in the crawl right now. Soon it will be tied into a fresh air damper with flex to ventilate the home. Will have a dedicated seperate return for the de-humid on the main floor and flex attached to the supply side of my main-floor hvac. This will put the main floor under posistive pressure when ventilating

I would strongly suggest a product called FST (foundation seal tape) It can be found at crawlspaceinfo.com it is a very strong and durable product that adheres well to foundation walls, there are also plenty more products available on that site that will help you with properly encapsulating your crawlspace. Also there is a lot of information that will help you ensure that you are encapsulating your crawlspace correctly.

I may be misreading, but it sounds like the crux of your issue is the moisture. If you get rid of that, you'll get rid of the other underlying symptoms. If you live in a moist area (i.e., not desert) and the floor of the crawl space is lower than surrounding grade, it will likely collect water and must be drained. Some sort of gravity drain usually works.

What I most always recommend, is some sort of constant mechanicalle powered ventillation of the crawl space (a fan). That most ALWAYS gets rid of the problem with a very low air volume.
Also, for natural ventillation, IRC requires (I think, may have to check exact) 10 square inches of open vent into the crawl space for every 150 square feet of footprint. That means if it's covered w/ screen, it may need a lot more. As a minimum. Forced air eliminates guessing.