bad news from terminix

RodneyWright · **Posted:** Thu Jul 21, 2011 9:09 pm

Frank Catena wrote:

Remember to seal the vents too when you're in there. The old advice about opening them in the summer and closing in the winter has changed. In bad situations, I've seen some homes with dehumidifiers too.

All this assumes no water in your crawl space. If you have water/drainage issues you need to deal with that first but its sounds like you're OK there.. If the ground is just damp the vapor barrier should be fine.

Another thing to check is that any A/C condensation drains are properly sending the water outside your foundation. Should be easy to check in this humidity.

Frank

Yeah, that was part of the condition, close the vents which is counter intuitive to EVERYTHING I've been told in the past. He said they've been recommending this configuration for the last 8 years and have had very good success. Off to Lowes and HD this weekend. He even went so far as to say that new construction w/ a crawl space are no longer requiring to have vents installed.

DickRasmussen · **Posted:** Fri Jul 22, 2011 7:30 am

The "close the vents" (actually "seal the vents") is legit. A heavy duty study was done in Eastern NC that proved it is better. In our climate it is so humid outside in most of the summer that the vents are not going to lower crawl space humidity.

We spent "big bucks" to get a "fancy" system from these guys, including a dehumidfier and sump pump, and are very pleased with it. http://www.basementsystems.com/basement ... ofing.html. We needed something that would allow the crawl space which is relatively tall in some areas to serve as a "dry basement storage area".

If you do the do-it-yourself approach you need to tape the seams really well.

Dick

RodneyWright · **Posted:** Fri Jul 22, 2011 8:39 am

DickRasmussen wrote:

The "close the vents" (actually "seal the vents") is legit. A heavy duty study was done in Eastern NC that proved it is better. In our climate it is so humid outside in most of the summer that the vents are not going to lower crawl space humidity.

We spent "big bucks" to get a "fancy" system from these guys, including a dehumidfier and sump pump, and are very pleased with it. http://www.basementsystems.com/basement ... ofing.html. We needed something that would allow the crawl space which is relatively tall in some areas to serve as a "dry basement storage area".

If you do the do-it-yourself approach you need to tape the seams really well.

Dick

Actually no tape required, just need to have a 12" overlap. As to Matt's point, yes, it needs to be pinned or staked down so it wont slide when you walk on it.

Richard Casto · **Posted:** Fri Jul 22, 2011 9:01 am

RodneyWright wrote:

DickRasmussen wrote:

The "close the vents" (actually "seal the vents") is legit. A heavy duty study was done in Eastern NC that proved it is better. In our climate it is so humid outside in most of the summer that the vents are not going to lower crawl space humidity.

We spent "big bucks" to get a "fancy" system from these guys, including a dehumidfier and sump pump, and are very pleased with it. http://www.basementsystems.com/basement ... ofing.html. We needed something that would allow the crawl space which is relatively tall in some areas to serve as a "dry basement storage area".

If you do the do-it-yourself approach you need to tape the seams really well.

Dick

Actually no tape required, just need to have a 12" overlap. As to Matt's point, yes, it needs to be pinned or staked down so it wont slide when you walk on it.

I have done this on both of my houses (current and previous) and it works wonders. The before after difference is amazing.

I have not heard of pinning or staking, but then again mine is mostly level and it does not move at all when I walk upon it. I can see if you have a significant change in elevation (more than a few feet) that something might need to be done.

I do think you should to lay down a double layer on high traffic area such as the entry way. My crawl space is large enough that I can use it for storage, so the extra layer helps prevent against accidental puncture. Regarding taping, I think it should absolutely be done in addition to overlap. Maybe that is why mine doesn't slide around. Taping the seams is very easy to do. Lowes/Home Depot WILL have 6mil plastic plus tape for this. I think that same tape is used when they wrap and seal Tyvek on houses. You should also seal/connect (using using some type of caulk, nail strip, or combo) the plastic against the interior brick/block walls as well. All of this is an easy DIY project. It should only be hard if you have a very low crawlspace you say you are in the 3-4' range, so I expect it shouldn't be terrible.

If you Google this, you will find plenty of "how to". Years ago the idea was to leave the ground uncovered, or to put down plastic, but leave open areas to let the ground "breath". This is so much BS. All it does is allows moisture to exit the soil and most likely there is an unending supply in the ground, so it never really dries out.

Charlie Guthrie · **Joined:** Thu Aug 28, 2003 8:14 pm **Posts:** 832

Rodney you stated

Quote:

As to Matt's point, yes, it needs to be pinned or staked down so it wont slide when you walk on it.

If it is 3' to 4' high I just don't picture YOU walking on it :lol:

I did this many years ago and the difference was amazing in keeping mold and mildew from growing on the floor joists. I didn't bother with the tape; just went with the overlap. As I recall, this is "cake work". Just drag the roll of plastic to the high side and let it unroll down hill. The hardest part was unfolding the multi-fold parts (since the roll is only about 4' long, but it is folded over a few times to get the larger widths (12').

And for the record, 6 mils is actually 0.006" (six thousandths of an inch). It is another one of those weird terms like "M" for thousands instead of millions - just because the Romans thought of it before Napoleon came up with the Metric system.

At any rate by now you are probably already finished and drinking beer... I know I am

Charlie G

Scott Johnson · **Posted:** Mon Jul 25, 2011 11:28 am

You will need to tape all of the seams together, and ideally, tape everything to the foundation walls.

clinehall · **Posted:** Mon Jul 25, 2011 2:09 pm

Ok, now what about the idea I have heard about "hanging" insulation on the side of the foundation? I have heard that takes insulation to a much higher level Doesn't have anything to do with moisture but while down there might be the time to do this also. My new hobby is making my home more effecient, my next thing to research are the new attic blanket insulations, anybody know about that?

Scott Johnson · **Posted:** Mon Jul 25, 2011 3:20 pm

clinehall wrote:

Ok, now what about the idea I have heard about "hanging" insulation on the side of the foundation? I have heard that takes insulation to a much higher level Doesn't have anything to do with moisture but while down there might be the time to do this also. My new hobby is making my home more effecient, my next thing to research are the new attic blanket insulations, anybody know about that?

My recent reading indicates that in southern climates it isn't needed. Our ground temperature is never very hot/cold.

This is a timely thread, my new house has a lot of work done in the crawl space (vapor barrier, some gravel, sump pump), and is pretty dry, but I still get a ton of condensation on the AC parts). The vapor barrier doesn't go up on the walls, and I was thinking of doing that, closing the vents, and possibly adding a dehumidifier if needed.

I don't have any mold/fungus issues, but the condensation on the AC unit is making it rust.

Charlie Guthrie · **Joined:** Thu Aug 28, 2003 8:14 pm **Posts:** 832

Scott, if your AC unit is in the basement, where does the condensate line drain to? I'm assuming that the compressor is outside and the cooling coils are in the basement, is that correct?
Do you have the flex ducts for the air to the rooms or is there metal ducts with duct wrap? What I have found is that unless the duct insulation is seamless or very well taped, condensation forms inside the duct insulation during the cooling months. I found one duct line that needed a drain hole because it was sweating so badly inside the insulation (before I replaced the duct).
Charlie G

DickRasmussen · **Posted:** Mon Jul 25, 2011 8:37 pm

Scott,

Based on the reading I did in 2006 the basic "bottom line" is to close and seal the vents and any other opening to the humid outside world. If your crawl space is dry already, that may be enough.

If not the link posted above also includes a dehumidfier and may have enough other information on their site or similar ones to allow you to "simulate" anything else you need without have to buy a full pricey installation like we did to solve our situation.

We did get what we paid for even though it was expensive. Since we use the crawl space for storage, having a bright white floor and walls combined with a nice dry atmosphere is really nice.

Dick

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