New Home Begins

[tkappeler]

When they finished the plates, they completed the T&G and started on the Raycore roof panels. [/ATTACH]

tkappeler, will the installers use any type of spray foam (such as Great Stuff) between the Raycore panels to fill in any gaps, if needed?

Yes, spray foam to fill gaps and then metal foil tape the same as they did with the walls.

 

[s219]

Great thread! We're building right now too, and it's familiar to read about someone else battling all the rain/snow/wind this winter. For a while, I bet we were out of action at least 2-3 days per week, which really slows progress. Seems like just as soon as the ground dries up and I think about getting in there with a tractor, it rains again...

 

[tkappeler]

Great thread! We're building right now too, and it's familiar to read about someone else battling all the rain/snow/wind this winter. For a while, I bet we were out of action at least 2-3 days per week, which really slows progress. Seems like just as soon as the ground dries up and I think about getting in there with a tractor, it rains again...

Yes, and the weather adds to the costs:

Extend portable toilet 1 month
Extend rental of telehandler by two weeks
Rent 2" diaphragm pump 3 times
Rent 2" hoses for connection to permanent sump 3 times
Buy tarps

and so on

 

[tkappeler]

The framers got all of the raycore panels up today. The temporary support in the middle of the great room has been removed and the remaining collar tie installed. All plates are up and finished, Funny how when you encounter something new, its always the last one to do that you finally have it down to a science and it goes quickly.

The front gable has it's panels installed too.

Next up:

Sheath the front gable.
Finish panels in back gable and sheath
build and install gable overhangs.
purlins and sheathing
crickets

Then sheathing inspection only a few days away

Unfortunately, it's snowing now. Not expecting more than an inch or two. Supposed to end by 2AM. but we will see if they can work tomorrow.

The excavator also called today to say that he has 15 truckloads of fill he can bring by for $50 per triaxle. It saves him and me since he will be removing it from one location and rather than dump it back at his place, he can just bring it here and save a loading charge. I will also have him bring over his smaller dozer to make the ramp to the garage and build up around it so I can get my tractor into the garage to finish there. His equipment is too big to be of much use there.

 

[jinman]

I love your roof, Tom. That T&G over beams is the 'cat's meow' as far as I'm concerned. I like mine as well today as 11 years ago when it was installed. I think everyone will "Ooh!" and "Ahh!" when they see your room.:thumbsup:

 

[dstig1]

No, there won't be another layer of foam. Yes, i understand the thermal bridging, but it is still far better than a typical attic with stapled up R30 or insufficient or matted down blown in insulation.

Well insufficient insulation is insufficient, no matter what. A proper blown-in insulation job in trusses (for example - not your situation, I know...) covers the trusses with a very thick layer of cellulose or fiberglass and covers the framing members totally, eliminating the thermal bridging problem. In your case, you can over-deck the panels with a layer of foam and do the same thing here. 1" of polyiso foam would help a lot, again sealing the seams as they did with the Raycore panels. Right now you have direct thermal bridges to the outside that bypass the insulation. You can prevent this issue now (yes, it will cost money - probably a couple grand depending on roof area), but it will be very hard to fix later. You may find you will have serious ice dam problems, depending on how your climate is. If the snow never sticks around for long, then probably not so big a deal, but if it does, the risk of big problems goes up.

I'm guessing those are 2x6's in the panels. Polyiso is ~R7.2 per inch. A 2x6 is listed at R6.9 (lumber is roughly R1.33/inch). 5.5" of foam is R39.6, so you have ~R40 insulation with R7 "bars" regularly spaced. You will undoubtedly see the lines a day after a snowfall.

I realize you can't do everything, but I'm hoping you find this input helpful.

-Dave

 

[tkappeler]

Well insufficient insulation is insufficient, no matter what. A proper blown-in insulation job in trusses (for example - not your situation, I know...) covers the trusses with a very thick layer of cellulose or fiberglass and covers the framing members totally, eliminating the thermal bridging problem. In your case, you can over-deck the panels with a layer of foam and do the same thing here. 1" of polyiso foam would help a lot, again sealing the seams as they did with the Raycore panels. Right now you have direct thermal bridges to the outside that bypass the insulation. You can prevent this issue now (yes, it will cost money - probably a couple grand depending on roof area), but it will be very hard to fix later. You may find you will have serious ice dam problems, depending on how your climate is. If the snow never sticks around for long, then probably not so big a deal, but if it does, the risk of big problems goes up.

I'm guessing those are 2x6's in the panels. Polyiso is ~R7.2 per inch. A 2x6 is listed at R6.9 (lumber is roughly R1.33/inch). 5.5" of foam is R39.6, so you have ~R40 insulation with R7 "bars" regularly spaced. You will undoubtedly see the lines a day after a snowfall.

I realize you can't do everything, but I'm hoping you find this input helpful.

-Dave

Dave,
Thanks for the input Dave.

Yes, I do find the advice helpful as I enjoy the opinions and knowledge of the people here very much. The only thing I know for certain is that more information is helpful. I do plan on doing some layer of blow in insulation over the batts in the truss areas. When I responded before, I was talking about how homes, at least around here, are typically done around here ... shoddy in many instances.

I will consider adding to the panel before they put the purlins and decking on.

Tom

 

[Ranger Rick]

I think even though there is some thermal bridging in the SIP panels they do meet the insulation code for your region and additional insulation to eliminate the bridging would have a long payback. I think that your money would be better spent making sure all the cracks and holes in the building are sealed tight so that there is not air infiltration into your house. just my :2cents::2cents: Rick

 

[dstig1]

I understand your point Rick on overall roof R-value averaged, but I disagree. In this case, the thermal bridging is excessive, IMHO. This is the roof, and insulation standards are higher on the roof for good reasons.. Hot air rises, so the roof tends to lose more heat than walls do, so that is one reason it is important to have good roof insulation.. The other one is ice dams. If the roof gets too warm, the snow melts, runs down and then refreezes when it hits the eaves, and this causes backups of ice and thus ice dams. This leads to roof leaks. Thermal bridges like this one lead to ice dams as the bridges melt snow in that area, and then the water runs down, even though the rest of the roof is cold. This is not like a typical SIPs roof panel as there are full 2x's in the panels, every 24" (or so it appears from the pics). Most SIPs roofs have I-joist splines which limit the thermal bridge to almost nothing (the thickness of the plywood web).

Given that he was already putting down T&G sheathing, I bet this could have been done with only foam board insulation and then sheathing over that, for something to nail the shingles to. I'm not sure the panels really add much structural here, though the bent spacing below may be a bit large for just 3/4" T&G to work. Still, it could be worked out without thermal bridges, I'm sure. 6" of polyiso is R43.2, which is just above the R38 code for TKappler's area (Based on a quick Google search), which is probably better than he is getting with the roof now. Lets say 5.5" of polyiso = 39.6 and the 1.5" wide 2x6's are R6.9 (per above). A weighted average says that means the whole roof should be rated at about R37.5 (linear average) which means it technically does not pass. Now you add a little extra for the T&G and it is probably over R38 total, but not by a lot.

If it was me here, I would add 2" of foam over the top of this. Ideally, 2x 1" layers offset seams, and seams sealed. Or just do the 6" foam and skip the panels, depending on load limits.

Like I said, you can't do everything, but the roof is pretty important, IMHO.

 

[tkappeler]

I understand your point Rick on overall roof R-value averaged, but I disagree. In this case, the thermal bridging is excessive, IMHO. This is the roof, and insulation standards are higher on the roof for good reasons.. Hot air rises, so the roof tends to lose more heat than walls do, so that is one reason it is important to have good roof insulation.. The other one is ice dams. If the roof gets too warm, the snow melts, runs down and then refreezes when it hits the eaves, and this causes backups of ice and thus ice dams. This leads to roof leaks. Thermal bridges like this one lead to ice dams as the bridges melt snow in that area, and then the water runs down, even though the rest of the roof is cold. This is not like a typical SIPs roof panel as there are full 2x's in the panels, every 24" (or so it appears from the pics). Most SIPs roofs have I-joist splines which limit the thermal bridge to almost nothing (the thickness of the plywood web).

Given that he was already putting down T&G sheathing, I bet this could have been done with only foam board insulation and then sheathing over that, for something to nail the shingles to. I'm not sure the panels really add much structural here, though the bent spacing below may be a bit large for just 3/4" T&G to work. Still, it could be worked out without thermal bridges, I'm sure. 6" of polyiso is R43.2, which is just above the R38 code for TKappler's area (Based on a quick Google search), which is probably better than he is getting with the roof now. Lets say 5.5" of polyiso = 39.6 and the 1.5" wide 2x6's are R6.9 (per above). A weighted average says that means the whole roof should be rated at about R37.5 (linear average) which means it technically does not pass. Now you add a little extra for the T&G and it is probably over R38 total, but not by a lot.

If it was me here, I would add 2" of foam over the top of this. Ideally, 2x 1" layers offset seams, and seams sealed. Or just do the 6" foam and skip the panels, depending on load limits.

Like I said, you can't do everything, but the roof is pretty important, IMHO.

Dave,

I appreciate the insight and I am going to consider it. And I do not want to start a war like the earlier concrete fiasco several pages back.

Maybe I am missing something and I apologize if it seems silly but ... haven't homes been built for the better part of the last century with thermally bridged walls and imperfect installed and undersized insulation? Haven't these same homes had less than adequate attic insulation too? Aren't all walls other than a double wall and SIPs thermally bridged?They all have not succumbed to ice damming.

edit: I did look into SIPs for the roof, however; to get anywhere near an R40, I had to have almost 12" thick panels and this was not going to work, either aesthetically or from an expense standpoint.

The figures stated by raycore, along with installation techniques are all reviewed and approved by the architect, structural engineer and township inspectors.

I am doing what I feel I can afford to do to make a tight home. I am NOT trying to make a superinsulated or I would have double walls and owned a bank. The whole green drive can't be a all or nothing camp. Incremental advancements have a place and it is far better than 90% of the homes, at a fraction of the cost, of those in the area, including some McMansions.

Two years ago, the attic insulation standard in NJ was R30. Does this mean that a mere R39 is paltry? If I compare to the neighbor who built two years ago, I am still better than he is.

Sorry, let me put the soapbox away.