Replies

1. 
   bill_1010 | Mar 26, 2002 05:00am | #1

   Seems like i could work. But to prevent compression of the rigid foam, add sleepers like you would on a slab floor. And place the foam to fit between the sleepers probably 24oc. Slap in some foam spray to seal it up.

   Thats one way, probably others as well and they might be better.

2. 
   Fred_Lugano | Mar 26, 2002 06:10am | #2

   Dear Bob,

   I was luck to have a client years ago who had an irrational fear of snakes. She made build her addition floor with a tight plywood skin across the bottom of the joists. I remember thinking, well it's her money.

   Everything went well, but I was particularly impressed with the results in the floor. Very solid, very warm. Since then, I do every floor over an open outdoor space this way. We build the floor system completely enclosed and blow the bays with cels. It's beautiful. No rodents, bugs, moisture, or fire danger.

   Regards, Fred

   [email protected]

1. 
   Davo304 | Mar 26, 2002 07:32am | #3

   Fred,

   What size and type of plywood do you use when building this exposed system? Do you use say, 1/2 inch treated, or exterior grade 1/4 inch luan?  What?

   Any tricks to installing this exposed sheathing, or does one simply have to lay on his back and work in the mud?

   Thanks.

   Davo

1. 
   Fred_Lugano | Mar 26, 2002 08:39am | #4

   Dear Davo,

   I'm partial to plain old 7/16 OSB b/c it's cheap. I think 1/4 would be fine, maybe easier to handle too. We prop it up with our knees or feet and air staple it. New construction code wants 18" min from joists to ground.

   I never allow crew to wallow in even dry dirt. We always roll out Tu-Tuf and stay on top of it. It makes sliding around in a tight crawl more fum too.

   Tell you a story that just came to mind. I was rehabing an old barn for a client that wanted a photo studio. It was right next to RR tracks and the crawl was so tight, my nose was into the OSB. Couldn't even roll over. I had to screw the sheets up with a battery right angle drill.

   So along comes a freight train and the entire building starts vibrating violently. The ground too. The noise off the tracks is amplied and I'm thinking I'm going to die. So I panic, let go of everything, and try to swim backstroke out of there fast. Meanwhile the loose end of the OSB is flapping and smacking me in the face. Took a good grinding on it. Of course the train was long gone by the time I got out. Maybe I'll forget the whole thing again very soon.

   Wondering how the hell I got into the crawl space business to begin with, Fred

   [email protected]

1. 
   coonass | Mar 26, 2002 02:40pm | #5

   bob,

   On new work we run ledgers the length of the joist from above and drop in foam and seal with squirt foam. No crawling.

   KK

2. 
   Davo304 | Apr 09, 2002 09:17am | #8

   Fred,

   Good story! Made me chuckle!

   The tightest , confined space I ever was in was when I was about 18 years old, working  for a contractor doing repairs to an Air Products oxygen plant. The "cold box" ( a huge square shaped tank filled with rockwool insulation that insulated liquid nitogen lines) had some frozen lines that needed thawed out. We had to remove a steel cover plate, dig out the frozen insulation, and thaw out the pipes with a blow torch.  The pipes were situated about 6 feet below the top opening, and we dug the insulation out with long handled rakes. 

   To thaw the pipes out, you had to be lowered head first down into the hole. You then had to scoot on your back about another 6 feet inward and the pipes were right above your face....about 9 inches between my nose and those darn pipes.

   Well, I had a "safety man" out on top of the deck. His job was to monitor air samples and to eventually pull my butt out of there, since there was no room to roll over and get out on your own. This "man" was just a kid like me, who, unfortunately for me had been out partying all night the day before.  He had a hangover, and the "runs."  Every few minutes he would leave to go to the rest room...all the while leaving me in that darn hole.

   Boy was I getting claustrophopic!  Finally, he just disappeared. Forty minutes later, after a lot of hollering and cussing by me, he finally came back and pulled me out.  It was about that time that I then re-lit the blow torch and had serious thoughts about literally "lighting him up!" Good thing for him that he was a fast runner!  To this day, we are still good friends, and can now both laugh about that day.

   Davo

2. 
   wflather | Mar 26, 2002 07:16pm | #6

   THis discussion make me feel better about my approach to insulating two new rooms under construction in my barn.  On top of the existing log joists we put down 1x12 shiplapped hemlock, overlaid with 2x6s tapered to bring the finish floor level and topped it off with t&g 2x6s. The joist bays were then dense packed with cells.  Walls against the stone walls are framed out with 2x4s providing 4-6" of space for more cellulose and the ceiling joists are 2x10s also to be blown with cellulose.  I am contracting out the cellulose, they are going to wet-blow the walls this Friday, this is not something I have seen done, so I will be on hand with camera.

   Picture shows floor before finish floor has been laid.

   Fred, you posted a message critical of unvented gas heaters.  I have been considering one of these, but was concerned about the water vapor introduced by these heaters.  Are vented gas heaters any better as space heaters?  I still haven't figured out how to heat these spaces.  One will be a woodshop and I expect insurance will have a conniption with an open flame.

   Thanks, wsf

1. 
   Fred_Lugano | Mar 27, 2002 05:55am | #7

   Dear W,

   Beautiful looking project.

   Walk away from unvented combustion. The water vapor is no good for the house. But there is a bunch of other nasty stuff that is no good for people inside.

   I have installed both Kerosene and gas Japanese units. They can be fitted with extra long vent/intake tubes to clear deep walls.

   Beep splintergoupie and ask her about the nifty wall mounted gas heaters she found. They had some advantages too.

   Regards, Fred

   [email protected]