tested for air leaks with some incense and found some surprises

strider3700 · 12-05-10, 02:00 AM

I've been worrying about and working at sealing my first house and now this one for the last almost 6 years so I'm not new at this but tonight I ran around with a stick of incense wanting to track down the source of a breeze and found some surprises.

To do the testing I turned off any fans, namely my woodstove fan and the furnace fan. The woodstove was lite and drawing lots of air. I don't have an external air supply so it was going to be sucking lots in. Then I just went around with a stick of incense and watched to see where it obviously moved. Here are the things that popped out.

I've previously posted pictures of my electric panel with no insulation around it and an obvious breeze. It leaks, badly. It also has a nice chimney affect, hold the stick near the bottom and watch the smoke blow away from the wall. Hold it near the top and watch the smoke get sucked in to the wall.

All of the windows that I have not worked on had places with drafts coming through. Nothing shocking but a fair amount. What I did find surprising was how much of an air current was coming from the center of the panes of glass. It had to be just from the hot air cooling and dropping as it got near the cold glass (it's -2 outside right now) I really need to ditch these fashionable mini blinds and get something insulating on those windows for the winters at least.

The windows I did seal had no obvious drafts.

My cold room had no obvious drafts around the bottom, the door or the top.

The bottom of the wall that I just spent all of that time fixing had an obvious draft coming out from under it. My guess is the cold is coming in going down behind the rigid insulation and coming out at that bottom. I didn't spray foam to the bottom floor but I will be now.

The walls that I haven't fixed have spots that are completely sealed at the sill plate and parts that had decent drafts.

The hole for the dryer vent leaks badly so does most of the openings for the external plumbing.

After finding all of these however I found the worst of them all and it's easily the dumbest one of the bunch. I have my HAM ticket and run antenna and ground wires into my office. To do this I've added a 2x4 block with holes for the wires into the window where it opens. I added weather stripping and insulated the holes and taped them up before closing and locking the window back on it. That side seals well. What I didn't notice was the weather stripping on the back of the window is 1/8" too short when the window is partially open. So I've had a gap 1/8" x2' wide open for a year and a half. No wonder my desk right below that gap is always so cold. For tonight I've jammed some thin foam in the gap but I will be getting some backer rod to put in there. Long term I'll probably add a proper case to pass wires through but that will be a ways off.

Anyways tonights 5 minutes of testing found me months of work to properly fix. No need to check upstairs yet

Ryland · 12-05-10, 11:04 AM

On my house we found that most of the air was coming in to the floor joist areas where the floor joists meet the outside walls and filtering up between the floor boards and in to inside walls, this is not something you can easly find with your method but in alot of houses is a big problem.
also where wood rests on top of foundation walls is another area that you get air leaks, spray foam and caulk can help out alot.

The other day I got to use a bulk can of spray foam, size of a propane tank like you use for grilling out (16 pound) the 6 foot hose on it had a small ball valve and a 8" needle like brass tube/straw, it allowed you to poke that straw in to extremely tight areas and fill them, it was about $80 for the 16 pound can but I was otherwise paying $17 for 24 ounce cans with my Great Stuff pro gun, that foam gun takes the mid sized cans, has a pistol grip and the valve is on the tip of the tube so it has extremely precise control, the other nice thing about the Great Stuff pro gun is that with the way the valve is set up on it a partly used can of foam can sit for months and still be good, where the single use smaller cans with the plastic straw you pretty much need to use within 24 hours or less before the are useless.

AC_Hacker · 12-05-10, 12:13 PM

This month's Fine Home Builder magazine has a very interesting article on building a well-sealed house.

The magazine is pretty expensive but the articles are good. If there is a library in your area it would be worth stopping in.

There have been other articles in the past on serious leak-sealing, that did mention the floor-joist leak problem, and also ceiling joist leak problems, and other areas that are often overlooked, too.

Regards,

-AC_Hacker

12-05-10, 02:00 AM	#1
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	tested for air leaks with some incense and found some surprises I've been worrying about and working at sealing my first house and now this one for the last almost 6 years so I'm not new at this but tonight I ran around with a stick of incense wanting to track down the source of a breeze and found some surprises. To do the testing I turned off any fans, namely my woodstove fan and the furnace fan. The woodstove was lite and drawing lots of air. I don't have an external air supply so it was going to be sucking lots in. Then I just went around with a stick of incense and watched to see where it obviously moved. Here are the things that popped out. I've previously posted pictures of my electric panel with no insulation around it and an obvious breeze. It leaks, badly. It also has a nice chimney affect, hold the stick near the bottom and watch the smoke blow away from the wall. Hold it near the top and watch the smoke get sucked in to the wall. All of the windows that I have not worked on had places with drafts coming through. Nothing shocking but a fair amount. What I did find surprising was how much of an air current was coming from the center of the panes of glass. It had to be just from the hot air cooling and dropping as it got near the cold glass (it's -2 outside right now) I really need to ditch these fashionable mini blinds and get something insulating on those windows for the winters at least. The windows I did seal had no obvious drafts. My cold room had no obvious drafts around the bottom, the door or the top. The bottom of the wall that I just spent all of that time fixing had an obvious draft coming out from under it. My guess is the cold is coming in going down behind the rigid insulation and coming out at that bottom. I didn't spray foam to the bottom floor but I will be now. The walls that I haven't fixed have spots that are completely sealed at the sill plate and parts that had decent drafts. The hole for the dryer vent leaks badly so does most of the openings for the external plumbing. After finding all of these however I found the worst of them all and it's easily the dumbest one of the bunch. I have my HAM ticket and run antenna and ground wires into my office. To do this I've added a 2x4 block with holes for the wires into the window where it opens. I added weather stripping and insulated the holes and taped them up before closing and locking the window back on it. That side seals well. What I didn't notice was the weather stripping on the back of the window is 1/8" too short when the window is partially open. So I've had a gap 1/8" x2' wide open for a year and a half. No wonder my desk right below that gap is always so cold. For tonight I've jammed some thin foam in the gap but I will be getting some backer rod to put in there. Long term I'll probably add a proper case to pass wires through but that will be a ways off. Anyways tonights 5 minutes of testing found me months of work to properly fix. No need to check upstairs yet

12-05-10, 12:13 PM	#3
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	Fine Home Builder... This month's Fine Home Builder magazine has a very interesting article on building a well-sealed house. The magazine is pretty expensive but the articles are good. If there is a library in your area it would be worth stopping in. There have been other articles in the past on serious leak-sealing, that did mention the floor-joist leak problem, and also ceiling joist leak problems, and other areas that are often overlooked, too. Regards, -AC_Hacker

12-05-10, 11:04 AM	#2
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	On my house we found that most of the air was coming in to the floor joist areas where the floor joists meet the outside walls and filtering up between the floor boards and in to inside walls, this is not something you can easly find with your method but in alot of houses is a big problem. also where wood rests on top of foundation walls is another area that you get air leaks, spray foam and caulk can help out alot. The other day I got to use a bulk can of spray foam, size of a propane tank like you use for grilling out (16 pound) the 6 foot hose on it had a small ball valve and a 8" needle like brass tube/straw, it allowed you to poke that straw in to extremely tight areas and fill them, it was about $80 for the 16 pound can but I was otherwise paying $17 for 24 ounce cans with my Great Stuff pro gun, that foam gun takes the mid sized cans, has a pistol grip and the valve is on the tip of the tube so it has extremely precise control, the other nice thing about the Great Stuff pro gun is that with the way the valve is set up on it a partly used can of foam can sit for months and still be good, where the single use smaller cans with the plastic straw you pretty much need to use within 24 hours or less before the are useless.