Here are a few points I would like to highlight that would make the sealed crawl space for your home a better product.
1. Try to get at least a 5% grade within your crawl.
-This makes sure rain that comes in before the roof and windows are up doesn’t just sit. Standing water makes for mold on your joists. Muddy crawls also potentially lead to unhappy contractors who would possibly not give the same results because they just wanted to get out of there. Ie: Plumming, Electrical, AC, Gas.
– Grading also allows water to flow down hill to the 1 low point to exit the foundation drain pipe.
-Youy’ll notice the floor is not installed yet and the sealed crawl team has the Thermax up and a skirting of 10 mil white secured behind the Thermax to pull down later. Allowing your crawl team to put thermax up while the floor is off greatly helps the team speed through the process and keep the Thermax shiney and reflectant for better performance. Once the floor is up the sheets would be dragged to the back of the crawl and Thermax many times dont look as good bringing less performance and slightly less eye appeal to the possible new home buyer.
– Try to make sure the graders level the ground properly as it is difficult once the roof is on.
*They usually have a mini track loader to push around dirt quickly.
Many times inspectors will ding them and you will have to go behind and fill low areas with sand. That’s time and $ and delays. Make sure they do it correctly the first time.
– Make sure the graders fill in next to the columns. 50% of the time its left to fill in … crawl space tech are paid by the job so they usually won’t fill them in due to it will take an extra hour.
so your home will have depressions covered by plastic around all the pillars.
– Make sure the final graders with the shovels and rakes get all the big stuff out. Sometimes the ground is hard and wont laydown. If that’s the way they leave it the crawl guys can’t push it around by hand…it would take far too much time, so that’s how it will stay.
2. Make sure plummers come back and seal their sewer pipe as it comes in below grade to the crawl. Many times a poorly performing team or a team in a rush will simply cover it up with dirt and seal the crawl. Down the road that will be the main source of moisture under the plastic and if enough gets in it will pool at the bottom and easily seap through the minute tape holes.
A good crawl team will bring their own caulk and caulk first thing..then seal around it leaving that area exposed so caulk cures… and leave a small roll of tape behind so someone can simply push dirt over pipe penetration and seal properly.
-Under grade penetrations should by hydro cemented by installers. Usually plummers.
If not all the water building up on the foundation face will find its way to that hole the plumbers made knocking a ½ block out of the wall to allow the plumming pipe in. If the sewer pipe comes in the top of the crawl is when most water problems happen afterwards.
3. If the crawl is wet and roof is up I would recommend putting a peice of thermax in the door that seals it and putting a few fans in crawl to evaporate the wetness. If its really bad 1-2 dehumidifiers would pull the majority of water out. I have dug trenches and placed a sump for really wet crawls. If the crawl is sealed with wet muddy ground it takes up to 2 years to dry out. No new homeowner wants to mush around on the plastic sinking into the ground as water seaps muddy through the tape. Never seal up wet. Recognize and mitigate weeks before sealing.
4. Best practice is that AC is installed and ready to run so crawl can be sealed. Try to have crawl door installed before crawl seal team comes. This will ensure the crawl team can seal the entire crawl properly. Within a day or sooner you will want your AC running to port fresh air throughout the crawl. If the turning on of the AC is delayed mold can easily begin to grow through the entire crawl. If so place 1-2 fans inside on high to keep air stirring so mold cant grow easily.
5. If the neighborhood has radon issues…you could test as the floor is installed for $105 Rudy ((919) 619-9448) 3 pCi/L and definitely if there over 4 pCi/L…have the architect team design it into the drawings.. Simply its porting a 3” pipe, 4” for larger homes from the crawl out the roof with no cap on top. During the building process that’s an inexpesive add on… afterwards its costly $$ and stands out being outside the home as a small eye sore.
6. Sill Plate Blue Foam Strip. Between the sill plate and the foundation wall are hundreds of gaps ..putting this very inexpensive 5 in wide thin foam strip down air seals from the sill plate to the top of the foundation wall. This also prevents a super highway for ants and bugs around your entire foundation. All bigger builders use this but many smaller builders I don’t see it placed.
7. If there are knee walls between the foundation wall and the sill plate… make sure the blue foam strip goes vertical at the end of the knee wall as the knee wall side is up against the foundation.
8. If you know it will be a sealed crawl have your installers who penetrate any knee wall use expanding fireblock foam to seal behind their penetrations. Not on the crawl ceilings but only on the walls.
100% Commitment Option
EPA offers special recognition to builders who commit to building 100% of their homes as ENERGY STAR. This commitment will be denoted with a special 100% icon on the ENERGY STAR Partner Locator once a builder has demonstrated progress toward fulfilling that commitment through the number of certified homes reported to EPA. Builders can track the number of homes they have built by visiting their My ENERGY STAR Account (MESA) at www.energystar.gov/MESA.
Add a radon pipe that starts 1 foot down from the crawl ceiling and runs through the home and out the roof uncapped. If Radon levels are high down the road or if anyone in the family smokes (radon is #2 cause of lung cancer) they can then simply add a radon fan for $125-$200.
To do it afterwards it will stick outside the home like a sore thumb and is expensive.