Insulating a crawl space

[Turdus]

My house has a crawl space under the family room. The space is 20 x 14, and about 4 feet underground. It is non ventilated, and has a dirt floor covered in gravel. The access to the crawl space is via a 2x3 opening from the basement.

I've had many problems with musty smells coming from the area. I thought it may have been moisture, but now think it is from rodents... mice, etc. The concrete walls are insulated with foiled backed insulation that runs from the joists to the dirt floor, attached with a fastener shot into the walls.

I've found that the mice are particularly fond of this insulation. I want to get rid of this and do one of two things:

1) not replace it

2) replace with some kind of board insulation, perhaps glued to the walls.

My question is: Does an area that is completely underground need to be insulated?

Thanks for your input.

[Steve Haynie]

Keep the floor insulated.

Is there a plastic moisture barrier on the ground in the crawl space? Excess moisture in the ground will cause a musty smell.

You would have to have a lot of rodents to get a strong smell.

[Turdus]

Steve,

The floor was covered in 6 mil plastic. We had a lot of rain last week, and I noticed the smell coming from the crawl space to be at an all time high. It had more of that dead rodent smell, so I went looking. I should mention that I run a dehumidifier in there, and it constantly runs. Also, the downspouts are properly set to carry water away from the house.

I lifted the plastic, and found 4 dead mice under it. I've also cut away the first 10 feet of wall insulation at the suspected entry point. It was covered in mice droppings. Saturated would be a better term... 25 years worth.

Thus my question. I'm thinking of pulling it all down, and either replacing it, or not.

There's some duct work that runs through there, but nothing else.

[landon w]

pull it down, they do the same thing in the attic. they love to use the insulation as nests. all they are doing is shitting and giving birth in your insulation. what good is it if youre constantly smelling dead mice, which btw is possibly the foulest odor in the world, plus lasts for months.

id pull it down. i cant see that it is doing anything for moisture or utility expense that you wont care to give up in order to not have to deal with the mice problem then decon the shit out of it.

GOOD LUCK, I AM VERY EMPATHETIC TO YOUR PROBLEM. i used to live out in the country, constant freakin battle!!!!

and it doesnt matter if you are a clean tidy person/family. If they want in, they get in.

[DaveH]

Trust me on this, I've been there and I've found the solution: Cleanspace. AKA total crawlspace encapsulation, this is the best thing since sliced bread, the floors are 20 mil reinforced and the walls are 8 or 10 mil (I don't recall). I had the same musty smell, constant dripping of condensate from the HVAC ducts, and high humidity (stayed in the 82% to 97% RH range all the time). Once I had the encapsulation done, ALL the issues were solved 100%. The RH dropped to the mid to upper 50% range, and all mustiness was gone. No more condensate dripping from ducts either. I added a Santa Fe dehumidifier, and my RH now stays 45% to 47% (I could go lower with it, but you don't need it that dry). I am 100% happy with this system. Anyone that tells you you have to have ventilation in your crawlspace is speaking from ignorance....if you vent, all you're doing is bringing in hot humid air from outside that breeds mustiness, mildew, and mold. This is exactly what you want to get rid of and /or prevent....they claim about 30% of the breathing air inside your living space comes up from the crawl. You will also have to upgrade your access door. Mine is 3' x 4', I bought a blem exterior metal door (hurricane type that opens to the outside) from HD, and cut both it and the frame down to fit the hole. I can email you some pics if you're interested in seeing what it all looks like.

Btw, you can foam sheet the walls after the CS install and get rid of all your floor insulation. If you go this route, get rid of it BEFORE the CS install to avoid a lot of cleanup.

[landon w]

hey dave, can you get me some pics and more info on that. My email can be seen in my profile, thanks

landon

[Turdus]

Dave,

Is crawlspace encapsulation something done by a home owner or pro?

[HAMERMAN]

Havent heard of that before. Sounds like a good solution.

Found this link which gives some info. It looks like a pro install is required:Cleanspace

[DaveH]

Turdus, it can be done either professionally or as DIY. I chose professional, since I wanted it done 'now' and didn't want to fight with it, I considered it cheaper more cost effective than giving up my own time, and the installation company gives a 25 year warranty on the installation and materials.

For those interested in DIY, check out this link: http://crawlspaceinfo.com/

If I can find them, I have a .pdf of an article from Home Builder Magazine about an independent running study done on different homes in different climates of before and after encapsulation, in every case it was an improvement. I also found a video a home inspector made of an actual inspection in which the home had Cleanspace....he is impressed with it and now recommends it.

When I was looking at doing it, I talked to my pest control man (he was old school), and he recommended against doing it, simply because he was going on conventional thought about needing ventilation. It's hard for some to get past that. Fast-forward to 9 months later when my next termite inspection came up....he has done a complete turn-around in his thinking on this stuff. His company is now considering offering installations, but I don't know where it will end up. One other thing, if your crawlspace floods and has standing water now, you need to address that before doing encapsulation.

Here's a few pics:

The door

The space:

[DaveH]

Here's an article similar to the one I was referring to, but the other one was done on homes in states ranging from NC to AZ.

http://www.advancedenergy.org/buildings/kn...wl%20Spaces.pdf

Here's another link with more info (the above .pdf was here):

http://www.crawlspaces.org/

There are codes mentioned about supplying a small amount of outdoor air into the return (positive pressure) for improved indoor air quality, etc....this is aimed more at new homes that are much more airtight I believe. Most homes that are a bit older have enough natural venting from air leaks that this isn't necessary. There are also codes mentioned about supplying approx. 35 cfm of conditioned air per 1000 ft2 of floorspace, but I haven't done this yet. It's easy to over-think these things IMO, and I've monitored conditions closely for the past 15 months or so, 8 of those months with encapsulation and a dehumidifier. I have absolutely ZERO ties or interest in the companies that make and/or install this stuff, but the difference it's made for me has me pretty wound up....I can't say enough good things about it, and wish I had jumped in a lot sooner than I did. If you have allergies, you will most likely notice some difference too.

Edited to add: Before doing all this, I had a 6 mil poly moisture barrier down on the floor of the crawl. While this is better than nothing, it comes NO WHERE CLOSE to what you get with encapsulation.

[backinit]

Turdus, it can be done either professionally or as DIY. I chose professional, since I wanted it done 'now' and didn't want to fight with it, I considered it cheaper more cost effective than giving up my own time, and the installation company gives a 25 year warranty on the installation and materials.

For those interested in DIY, check out this link: http://crawlspaceinfo.com/

If I can find them, I have a .pdf of an article from Home Builder Magazine about an independent running study done on different homes in different climates of before and after encapsulation, in every case it was an improvement. I also found a video a home inspector made of an actual inspection in which the home had Cleanspace....he is impressed with it and now recommends it.

When I was looking at doing it, I talked to my pest control man (he was old school), and he recommended against doing it, simply because he was going on conventional thought about needing ventilation. It's hard for some to get past that. Fast-forward to 9 months later when my next termite inspection came up....he has done a complete turn-around in his thinking on this stuff. His company is now considering offering installations, but I don't know where it will end up. One other thing, if your crawlspace floods and has standing water now, you need to address that before doing encapsulation.

Here's a few pics:

The door

The space:

Make sure you paint that door (all sides) and frame. The paint on the frame should have a little sheen to it as the weak area is where the jamb legs attach to the sill.

If that is the budget JW steel door from HD it will rust out in a few years without paint.

I work for a distributor that handles some JW products.

[LordOfTheThighs]

Live traps would keep the smell of dead rodents down.