Crawl Space Encapsulation - DIY Chatroom

Jimmy07 · 07-27-2009, 09:03 PM

Hello,

We would like to completely encapsulate our 900 sq. ft crawl space. Currently 6 mil barrier with five inches of pea gravel that is wet near pit because of defective sump pump.

I've been hearing a great deal about the Clean Advantage System and the EmeShield 60 mil liner with zero perm. Our thoughts are to have a 20 mil liner placed with 3-4 inch concrete. I am concerned with how little I have found about concrete being the preferred method. Is there something wrong with using concrete to encapsulate besides the temporary onslaught of moisture?

Thank You.

timchi29 · 07-27-2009, 10:19 PM

I had 4" of concrete poured last fall and it has been great. I sealed up the vents and with the dehumidifier, it maintains 65-70 degrees with 40% humidity. Since I use for storage, i installed a back up battery pump.

Red Squirrel · 07-27-2009, 10:30 PM

Quote:

Originally Posted by timchi29

I had 4" of concrete poured last fall and it has been great. I sealed up the vents and with the dehumidifier, it maintains 65-70 degrees with 40% humidity. Since I use for storage, i installed a back up battery pump.

For sure, I really don't see why some crawlspaces are not poured or why there are vents. The crawlspace is still part of the house and should be treated as such, especially on a split level house (half regular basement, half crawlspace). If you don't have any, get weeping tiles installed as well to take care of any water issues. Dampness is one thing but water issues can really be damaging to the foundation's integrity.

Painting the cement with drylock can probably help too. I want to do this with mine. I recently cleaned it all up from junk left over from previous owners, need to do some more vacuuming then prep for paint.

Jimmy07 · 07-27-2009, 11:33 PM

This is encouraging guys, thank you. A reputable builder/engineer that I know in Maine told me to make sure the perimeter edges of crawl are water sealed too.

Since the crawl is only four feet below the living area, we did research on quiet sump pumps. From what I have read the Red Lion fully submersible 1/3 HP 43 GPM cast iron pump is supposedly so quiet, that only water can be heard when discharging. That would be nice..

ARI001 · 07-28-2009, 09:56 AM

Quote:

Originally Posted by Red Squirrel

For sure, I really don't see why some crawlspaces are not poured or why there are vents.

Crawl spaces usually are not poured to keep costs down. I've explained in other posts why ventilation in non-conditioned crawlspaces is necessary. The reports have also come in now on energy usage and conditioned crawl spaces. It uses more energy (20% to 53% more) to condition the crawl space depending on the insulation methods used. Moisture levels in conditioned crawls are reduced by as much as 20%.

itsreallyconc · 07-28-2009, 07:01 PM

makes no difference since 1 has to deal w/crawl spaces as they are & usually not as we would like 'em to be,,, i like cross-ventilation w/humidistat-controll'd fans & fiber-reinforc'd 15mil vapor barrier on the btm,,, about as reasonable as can be done...

insulation between the floor joists, vapor barrier, & tiger teeth'll be a big help, too !

Red Squirrel · 07-28-2009, 11:48 PM

Quote:

Originally Posted by itsreallyconc

makes no difference since 1 has to deal w/crawl spaces as they are & usually not as we would like 'em to be,,, i like cross-ventilation w/humidistat-controll'd fans & fiber-reinforc'd 15mil vapor barrier on the btm,,, about as reasonable as can be done...

insulation between the floor joists, vapor barrier, & tiger teeth'll be a big help, too !

That sounds like a recipe for mold and lot of moisture. And I thought my crawlspace was bad lol...

Pics here of how mine looks like: http://gal.redsquirrel.me/?level=picture&id=502

Never really thought of insulating the joists though, but given heat rises, it will stay upstairs anyway while the crawlspace stays rather cool. I will use it as the cold isle for my server room.

ARI001 · 07-29-2009, 02:17 PM

Quote:

Originally Posted by Red Squirrel

That sounds like a recipe for mold and lot of moisture. And I thought my crawlspace was bad lol...

Pics here of how mine looks like: http://gal.redsquirrel.me/?level=picture&id=502

Never really thought of insulating the joists though, but given heat rises, it will stay upstairs anyway while the crawlspace stays rather cool. I will use it as the cold isle for my server room.

Actually based on the studies that have been done insulating your crawl space between the joists is more energy efficient then no insulation or insulating the walls only.

Ventilation is necessary in unconditioned crawl spaces and is required by code. Also a 6 mil vapor barrier on the floor area is required by code. Having controlled fans in the crawl will help prevent mold as it adds to the cross ventilation.