Insulation and the Service Cavity

I was going through some photos of construction of the house and realized that I didn't do any posts about the dense pack cellulose and the smart membrane, Intello Plus.

I was a little disappointed at the dense pack cellulose because the insulation contractor didn't do it like I had seen in videos and it didn't seem dense enough. I read that the installed cellulose is supposed to feel like a firm mattress, but ours only felt that way in some spots. I actually cut holes in several spots to see how well the cellulose held up and it didn't settle. It wasn't as dense as I would have liked, but I think it is adequate. I hope so in any case.

Here are some examples of the Intello Plus and the dense pack insulation. Also there are some areas around the second floor rim joist insulated with Roxul mineral wool insulation. You can see the 2" x 4" service chase on the walls, room for electrical and plumbing so it does not take up insulation space in the 2" x 6" wall space.

You can see the see the service chase in the kitchen much better here.

An Air Sealer's Work is Never Done

Well, we are back at it - working on the house again.

No, we do not have our construction loan yet.

Yes, the house is gradually nearing completion.

Yes, this drives me crazy. But we do have assurances that the construction loan will go through. Our contractor is willing to go ahead and get back on the house despite not having the actual loan yet. Thank you, Randy.

Anyway, so I am trying to get to some additional air sealing details. These photos show the water supply Pex tubing in the kitchen which runs from the mechanical room under the floor to the kitchen. In other words, this tubing bridges the thermal envelope. The plumbers sealed it with the orange foam in a can. You can see that the Pex tubing is not completely sealed to this extreme air sealer's standards. The orange foam doesn't cover the entire side. In addition if the tubing moves as in the 3rd photo, it opens up and fails to maintain the seal with the tubing.

So what does a good Air Sealing Specialist do? The choice is tapes or flexible sealants. For this area I choose tapes to make a good seal with the tubing.

I used Pro Clima Unitape with a flexible hole in the center to run the pipes through. 

Then I reinforced the seal with one of my favorite tapes - Pro Clima's Tescon Vana.  Love this stuff. I also use it on holes in my work jeans. 

For the vent pipe, I went with Siga Wigluv tape. 

One area I have to air seal and I don't really know how is around the electrical boxes.

It's not really needed because the boxes are in a space in front of the insulation layer and do not penetrate the thermal envelope. (Remember the thermal envelope on this house is sealed at 3 levels - taped on the exterior,  taped and caulked on the inside every single stud bay, then the dense pack cellulose was blown into the stud bay covered with a completely air sealed vapor permeable membrane, Intello Plus. I still like the idea of having redundant layers of air sealing layers so I do want to seal around the boxes. Not to mention that the inspector said we have to because that is where the thermal envelope is usually sealed and that is what they expect. But I don't really know how to do this. More internet study.

We are getting ready to tile the mechanical room because we need it so we can have some heat. We've chosen a wood look tile from Home Depot that is only $2.39 sq. ft. John really likes it. 

I'm going to install it over Schluter Ditra membrane to uncouple the tile from the floor to help prevent cracking. I figure in the laundry room I need to do that.

Well, that's sort of where we are now. Lots more going on - 4 inch red oak floors have already been  installed, doors will probably be installed tomorrow, followed by window trim. So we are getting somewhere. I'll try to keep you better informed the last half of this month. 

Proposed Wall assembly

Here is a drawing of the proposed wall assembly.

The R values (resistance to heat flow) of each layer of the assembly are outlined below:

2" x 6" stud wall = 5.5 inches x 3.5 R value/inch = 19.25
2" layers Roxul Comfort Board* = 2 inches x 4.2 R value/inch = 8.4
1.25" layer of Roxul Comfort Board or insulation in service chase = 1 inch x 4.2 R value/inch = 4.2

Total R value = 19.25 + 8.4 + 4.2 = 31.85

*I just looked at the Roxul website and the thickness of the Comfort Board is listed at 1.25", 1.5", 2", 3" so we may have an R-value about 2 higher if we use 2 layers of the 1.25" board.

Also we will probably use HardiPanels rather than HardieBoard sheathing.

3 postings in a 24 hour period. Pretty impressive, huh? I even skied a little bit today. Last day of skiing is tomorrow which always makes you a little sad.