I guess you buy a bunch of caulk and take back what you don't use?

Or make several trips, grabbing several cases at a time.

I dont know if I would have the patients to do 3900 sqft with a caulk gun and caulk.

Be sure to use smoke and a blower door to make sure you didn't miss anything.

After looking at the spray foam stuff again I am still considering that as well...

I dont know if I would have the patients to do 3900 sqft with a caulk gun and caulk.

7000 sf took me about two weeks. None of the patients were willing to help....

Well, I have the black jack roof coating in hand and was looking for a way to apply it. I was considering getting a harbor freight spray gun but I know with the ecoseal it requires a 2hp or larger compressor due to the thickness. I figure this stuff has the consistency of bed liner.

I picked up an undercoating gun for $10 off amazon which is used to apply beadliner and other think coatings like deck texture.

I might also try spraying straight calk through it just to see what happens. Double studded wall almost done so I will start with the air sealing soon.

How long before you go for the actual air sealing? I ma very interested in your results, as I will have to do the same thing in about a year. Please psot back your results. Thanks for sharing.

-John

ETA to air sealing, 2-3 days when the spray gun comes in from amazon.


Ok so here is a diagram of the latest design I was thinking of tonight.

I am concerned about the cellulose settling and I want to have at least what I have now (ok I think my existing house outer walls might have only r11 fiberglass with rigid foam on the other side.

So, everyone says to not flash and batt because if you only do an inch and it gets cold you will get condensation. I came up with this design.

Air barriers on each side.

Vapor and air barrier will be in the center of the double stud wall. This way there cant be condensation on the foam because it is insulated on both sides.

Key to the photo is as follows

Black = roof. Dark Gray = siding. Pink = traditonal fiberglass. Yellow = wood (sheatrock for the inner wall, sorry more colors made it confusing.) Light grey = cellulose Red = vented soffitt.

I know this idea has some controversy BUT - you will never have condensation on your foam. You have R13 on one side and R 19 on the other. The outer and inner walls are vapor permeable. This will mean that the vapor on the outside will remain outside. The vapor on the inside (unless removed) will remain on the inside.

I really like this idea.

Why?

Because cellulose, even packed, will settle over time. In this case the cellulose will not be exposed to the outside moisture causing it to settle more. Worst case scenario that there is a leak or otherwise, there will be a SEALED and ZERO THERMAL BRIDGED R13 outer layer of insulation.


Ideas thoughts... I will be video reviewing this build.

I used GE Level 1 Silicone calking.  I sealed all joints where plywood meets studs, prior to insulation.  I hired an insulation company, and they commented on the "great sealing job".  I went through 60 tubes of calking for my 2300 sq ft house.

Please stop sending me email updates every time this is updated!!!!

I have not signed up for this!!!

Putting the vapor retarders and air barriers in the middle of the stackup is a tried & true practice in Canada even before Larsen first built trusses with R19 fiberglass on the exterior. There's no reason it won't work for you.

If you have a vent space behind your siding, you don't even need a vapor retarder in VA, but both the interior & exterior need to be nominally air tight for thermal performance. In general stackups designed to not need vapor retarders are better off without them.

But you're dead wrong on your characterization of cellulose settling. Installed at sufficient density settling simply won't happen, and the required density can now be calculated (thanks to the work of Torben Valdbjørn Rasmussen over the decade or so.)

Nice part about this design, I can seal everything and leave the top of the inner sud wall accessible in the attic. In 5 years, as written in your other thread, It will not be an issue to crawl over and blow into the space between the double studded wall. Even if I cap the top with a 2x6 it is nothing to pop it up and force more cellulose down. Unfortunately, I dont think the lowes blow in tool will dense pack cellulose very well but I guess we will see unless I go with r19 fiberglass inside well. Either way, I think R30 something might be a bit of an overkill in this climate for the walls.

On the good side I actually used two bushels of green fiber as stuffing for a 6 foot heavy bag. It is a tad bit lighter than I thought it would be but that is good since I have to pull the bag down after each use so my wife can park her car there. The two little bushels that I got filled the entire bag and left over half of the second bushel half full. After several weeks of punching this bag the stuff settled a bit. However, even after opening the bag at the top there is still insulation flowing out. It simply packed further into the bottom of the bag and the insulation at the top simply expanded upward. It was still hard to put more in without it flying out of the top. I am impressed that the stuff has not compacted back down into almost nothing since I have been beating on it and no I dont hit it lightly.

As far as whoever is complaining about the email, I am not emailing you. I have no idea how to stop it from my end. However, you should be go into preferences and set it not to email you with updates to threads you posted in.

In some areas having the double-stud cavity continuous to the attic would technically be a code violation since there are no fire-blocks. At 3lbs density cellulose is it's own fire block, but that argument doesn't always fly with inspectors. Firestops made of rigid rock wool insulation panel probably would though, should that issue come up.

If I had an inspection I dont think they would catch it. Our builder didnt put down a vapor barrier under the house and they didnt catch that simply because the inspector wasnt going to crawl under the house to get to the new side of the crawl space.

So, I got my spray gun setup ready today to shoot the silicone based latex into the cracks. It isnt a airless system running at 2000psi or anything but I think it will work fine for my uses. I unfortunately could not start air sealing today. With my mother in law coming down from the 4th I spent the day helping to clean up this disaster. Since my house has been a constant state of construction for over the last year there is stuff everywhere. It also doesnt help that we are housing an elderly and sick cat along with the fact that I decided to tackle a heat pump water heater this weekend as well as finish a multirotor drone.

So I did some spraying tonight. I think it worked really well. Update to come!!!

Thanks for the update. I'm looking forward to all the gritty details once you get completed, including technique, how it looks after it cures, any issues while spraying (head clogs, running, fumes, application consistency, etc...)

You finally did decide on the black jack roof coating? If so, where did you pick it up?

Can you find a link to the gun you used, or something similar, or at least the make & model?

Ok so I used the bed liner gun and the Black Jack Roof coating tonight.

Video

Overall I am happy. I used one gallon on a 20x14 area with one coat. I want to do a second as well. This should be a very effective air seal. Was very fast to install.

How will the odor be after it cured? Very strong smelling?

Do you plan on doing a smoke test at any time? Guessing you can't since this is just an addition right? (currently living in another part of the house?)

As for the odor, right now it smells like I put a bunch of caulk in the walls. I hope that goes away soon but I dont think it will linger.

As for the blower door test, if I air seal the whole thing I could in theory do it. Since the builder was contracted to do this portion unfinished he put exterior doors between the outside and between the addition and the existing house. The only thing that is connected is the attic. If I insulate the attic more in the existing house first I could close off the attachment and do a test or just wait until I finish the ceiling.

I have almost considered getting another one of these be liner guns since at $10 they dont break the bank. I could then take both guns, hose clamp them together, and put two 45 degree pipe connectors on the nozzle. Then instead of blowing thick paint I could blow part a and part b of foam. I am sure that would piss a few spray foam contractors off. In fact I expect, like when I was putting in my own ac, to get a phone call tomorrow from a contractor in the field telling me how illegal it is to do that. Followed up shortly by another call exclaiming that the money I am saving is suppose to be their profit!!!