Fiberglas and Snakes and Moisture
I have an unheated walk out garage. There is fiberglas insulation held between the joists of the floor above by chicken wire stapled to the joist bottoms, with the kraft face against the subfloor above. This garage can get damp, especially since I upgraded the door. I’ve been unhappy about the insulation as it precludes checking for termites, etc. And it’s an ugly job.
I removed the insulation from two bays yesterday. After popping the staples on 6 feet or so of chicken wire, a batt fell to the floor. A three foot blacksnake rode it down. By the time I finished the second bay, I had three snakes. They were pretty lethargic and I guess that they are hibernating. Extrapolation suggests that I could have 25 or 30 more snakes hibernating under the floor of our great room. It doesn’t creep me out, but my wife is not at all happy.
Before I remove the remainder of the insulation, and snakes, I need to think about the replacement. Can I put rigid foam up against the bottom of the subfloor? I figure I can hold it in place with small cleats. What about the damp? Also, does anyone have any experience with borate wood treatments? I’d like to treat at least the sills.
Replies
No answers... just questions. Where do you feel the moisture is coming from? Through the slab, through the walls, or both? When you said walk out garage, that seems to insinuate that the garage is at least partially below grade - is that the case? What are the garage walls made of - masonry the entire height? Concrete? Masonry stem wall that is a foot or 2 tall? Is this like a basement garage? What I'm getting at is that if it is that damp in there you need to find a way to mitigate the moisture.
Is there any signs of moisture showing on the ceiling framing lumber (great room floor)? ie: mold or mildew? Would you happen to know if the garage concrete floor had plastic film installed before the concrete was poured?
As far as rigid foam insulation against the subfloor, that would be a good idea, with a few caveats: 1st: the rigid insulation would need to be sealed around the edges so that air would not leak or else the foam would be fairly ineffective. 2nd: at about R-5 per inch, what thickness of foam do you intend on using to get enough of a thermal barrier? 3rd: be aware that foam needs to be covered with something for fire safety reasons - usually drywall, but that would not work too well if it is damp down there.
Have you though about getting an insulation contractor in there to install spray in place foam? Although expensive it would probably be by far and away the best solution.
Edited 10/18/2004 7:05 am ET by DIRISHINME
I agree with all that Matt has covered, and will tell you that I am and have been using a lot of RFOAM boards in my shack. The 2'' is the thickest I can easily get here (KY) and it is about 20 bucks a board.
Now the tricks to installing it..I can't go by the prescore lines at 16 and 24" I cut the sheets with my cordless Circsaw almost all the way thru, then a swipe with a butcher knife.
As said ya have to seal the edges..if you ever tried to squirt foam into a small gap..you know what is wrong here. Ya have to leave a gap big enough for the straw..about a 1/4". All fine and dandy on a wall or floor but a cieling? UT OH..
I take a dedicated can of foam and after ALL the pcs. I will be using are PRECUT..put a dollop of foam on the back. A few prop sticks will hold it up, some long roofers toed into the joists thru the foam edges, anything to hold it up till it kinda stays.
Now have you ever used can foam overhead? NO FUN, the can must be upside down and the straw is only about 8" long..Major PITA, and a mess. Get ahold of enerfoam (lost the link,sorry) and get the big set up with a hose...much better..or a lot of little cans and some 1/4'' tubeing (disposable).
With all that said, I'd seriously look at a full spray on install ( can't here due to other circumstances) of a layer of insulmesh and cellulose.
Find the snake access and foam that for sure.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
Regarding the foam sealant: After sealing the rim joists in my home with the cans from HD, I bit the bullet & bought one of the foam guns with a stainless steel barrel. It was MUCH easier to use and I was much cleaner when done (I still have a foamy sweatshirt from the first experience). Econo guns run about $35 and the foam & cleaner are about $16 and $6 respectively. Economically it may not make sense for your application but it will be much faster and cleaner, plus you'll have a great tool for other airsealing you may need to do.
Here are some links if you're interested.
http://www.positive-energy.com/pages/SealingFoam2.html
http://www.sheltersupply.com/search_result.asp?CATEGORY=ALL&Manufacturer=illbruck+Sealant+Systems%2C+Inc.
Do you have to use the entire $16 canister at one time, or could you say, use some, and get it out again 2 months later and use up the rest of the can?
thanksMatt
Well, kill the damned snakes for sure! Everythng else is second place!
Nah. Not into killing them. Just don't want them to establish squatters' rights in the rafters.
Hey dont hurt ur resident predators! Theres only snakes because theres mice.Mice will destroy any kind of insulation, snakes dont.A black snake will not hang out in a very damp place so id say it couldnt of been too damp at least in the joist cavities.Good luck trying to keep the mice out uless u weld steel plates to the floor joist.Seems like chickens werent the original problem anyway.
Whoa up! I'm not the one that wanted them dead!
When I find a snake I take him up the road a piece and turn him loose on an old stone wall. Let him warm up and find a new den.
Before I put in the new (weather tight) overhead door, we would get mice when the weather got cold in the fall. I guess the snakes come in to hibernate, rather than feed, as the food source is dried up.
The snakes in the rafters don't creep me out. But given a choice between the two, I'd sooner loose them and keep Arlene.
Edited 10/20/2004 5:20 am ET by Patrick
Snakes in my shop are common....in the rafters and attic, too!
They can be a SURPRISE every now & then! Once a copperhead ( 1 in 30 years)...And this spring while welding on a bushhog in the shop a 6' speckled king dropped 10' out of the ceiling insulation to land about 2 feet behind my plumber's crack!
I opened the garage door and asked him to leave....off he went like he understood. I've run into him several times since then.
Come mid-december he will hole up. Not very many mice this year, either!
I did commence covering the ceiling with OSB! (Ouch $$$$$!!!!!) Snakes don't bother me......but DW and adult children are the opposite.
But as far as hibernation....never found one in a the building's structure, excavated a few during cold weather work.
Snakes prefer to use the moist soil below frost level for hibernation. This allows then not to dehydrate. The rafters of a house in the winter are often colder and much drier than necessary for survival during hibernation.
Although I have met a few women as cold and mean as an irritated snake.....I was lucky enough not to marry one that onery. Sounds like you did "okay", too!
.................Iron Helix
PS....I keep my snakes alive....even the copperhead, but he became a live specimen at a local State Park....lived there for 15 years....till it burned.
Edited 10/20/2004 6:35 am ET by Iron Helix
Why, they make their living eating everything you REALLY don't want around your house..
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Good question.
http://www.fomo.com/operation/A11370W.pdf
It says you should use the whole can within 30 days. I was told by the distributor that I could unscrew the can & it would last. I've had one since last winter & haven't tried it lately so I can't say if this is true. The cleaner worked very well & I put some into the foam can nozzle, so hopefully it will be okay. I don't think any seal is broken when you use it the first time, so its possible that it may still work.
I also recall hearing on This Old House that the gun foam cans have much more material than the straw ones but I can't confirm this. The link below says a 12 oz HandiFoam can will go 1750 ft w/ a 0.25" bead, so you can compare that to the HD cans.
http://www.fomo.com/about.html
An open can left on the gun will last for months & months if you have no leaks.
Joe H
The rear of the garage is partly below grade, and construction is stucco over block. I doubt any vapor barrier was placed below the concrete floor. This garage is a 50's-60's addition to an 1820's stone farmhouse. The original, adjoining basement is dry or mud/mortar laid stone.
In very wet weather, moisture will appear on the back walls. In extremely wet weather, I'll have some water on the floor. (Several weeks ago we had 7 inches of rain in 8-10 hours: Some water on the floor. If I'd forgotten to clean the gutters, there would have been a lot more.)
The good news is that I've never seen signs of moisture on the exposed framing. Still, I'm reluctant to cover all that wood. Does the spray on foam capture moisture? Or does it breathe? If I treat the wood with borates, are there implications for the foam application? Am I too worried about termites?
This garage is too small for auto use, so I hadn't planned on drywalling the ceiling. Besides, that sounded like building a new, deluxe snake condo.
RE: How do the snakes get in?
Several weeks ago, during the 7 inch rainfall, I saw the wife's cat batting at something at the back door. A small garter snake had pushed its head under the rubber of the threshold seal and 2 inches into the house. I guess he thought he was going to drown.
When we bought the house, the garage addition had only a barn type sliding door. I installed an insulated overhead door in the opening behind that. Last summer I found a good sized black snake sunbathing on the sliding door hardware. When it saw me, it pushed behind the rubber weather stripping at the edge of the top door panel and on into the garage. Also, I've read, snakes can get through very small openings.
On the other hand, we don't get mice coming in for the winter.
Thanks for the information. I just posted a reply to Matt, and posed some questions about moisture, wood, and termites. I would appreciate any insights you may have there.
Given the nature of the house, I doubt I'll be able to find, let alone seal, evry possible snake access. I think my goal is to eliminate the condos - Like the old glas insulation.