Home Construction 2 x4 or 2 x 6 framing

[waitingforbuyout]

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Originally Posted by deepc Here's a link that provides info, some already mentioned: http://www.energystar.gov/ia/home_im...doeframing.pdf If you look at the picture of the framed in window, you might notice that the 2x6 framing gives the opening a three dimensional feel of older construction that's less possible using 2x4 framing. Old houses feel cozy in part because they're substantial, the thick wall will contribute to that effect, provide large sills, and extra wall area to bounce light off of. The linked document suggests that due to material cost savings, it's a wash between 2x4 and 2x6. I'd imagine that's the case unless your contractor prefers (for whatever reason) to use 2x4, in which case they will make you pay through the nose to build using a technique they're unfamiliar with. If energy efficiency is your goal, you should talk to the contractor about passive measures that will provide far more savings than additional inches of insulation. Siting the house so that it takes advantage of passive solar, shielding from the predominant wind, well designed overhangs, materials, and equipment; all of the above plus the proper insulation is called for.

Passive Solar Properties ARE more important than insulation! I wish builders would site new homes properly to include orientation and landscape.

[kyounge1956]

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Originally Posted by Brat (snip) Spend a couple $ on time with an architect who has personnaly built his own home or find a member of the Constriction Specification Institute. Their architect members focus on materials.

that way you can squeeze every last benefit out of your construction dollar

[Zathras]

Insulation is a major part of any passive house design.
Yes, you can gain benifits from the proper facing and proper use of windows. But some of the best bang for your buck will be in better insulation. I-trusses are pretty popular due to the smaller amount of thermal bridging across the width of the wall and it is tough to beat 12 inches of insulation
Note, that much probably isn't needed in moderate climates, the passive and net zero houses I have seen in the Midwest tend to have 12 inch walls.

[Tyro]

I happen to have a degree in Construction as well, with specialization in solar/alternate energy systems (albeit class of '76). I'm familiar with everything being discussed here except cellulose blown-in wet. Back when I was doing it, we blew it in dry, and it had a propensity to settle over time, so was only used in retro applications. I cannot speak for the wet product, but I'd investigate it more, and how it's supposed to dry out in an otherwise "tight" construction.

If it were me, building in Michigan, I would go with a 2x6 wall with fiberglass insulation between the studs, and 1" foam "wrapper" outside, with taped joints. Foam can be sprayed to fill gaps around windows. Regardless of the type of insulation used, it's critical that a vapor barrier be installed on the living space side of the studs. I would use 12-18" of insulation in the attic ceiling.

I agree most heat loss occurs through ceilings, windows, & doors, but IMO that is no reason to cut corners on wall construction. If heat loss was everything, houses would be made of rigid insulation, but solidity and tightness against drafts also contribute to energy efficiency. All windows should be double-glazed; triple-glazed on the north side, and north windows kept to a minimum. Unless large windows are an aesthetic choice, only 10% of floorspace is usually required to be windowed -- check local codes.

The house I live in now (I didn't design or build it) is built very tight, but still, caulking the outside cracks & gaps, and installing foam insulating sheets behind all the switches & outlets has had a noticable difference.

Site orientation/passive solar is, IMO, always part of the whole design package (or should be -- it's often compromised in developments where buyers pick from a selection of "stock" plans) and lot choice can have a bearing as well.

There are more considerations; there's a LOT to building an energy efficient home, but it's late, and I'm tired.

If someone is going to lay out 6 figures to build, IMO, it's worth 2-3 figures on a few good books to learn about good design & construction. It's YOUR castle.

Tyro

[hakuna matata]

Quote:

Originally Posted by Tyro If it were me, building in Michigan, I would go with a 2x6 wall with fiberglass insulation between the studs, and 1" foam "wrapper" outside, with taped joints. Foam can be sprayed to fill gaps around windows. Regardless of the type of insulation used, it's critical that a vapor barrier be installed on the living space side of the studs. I would use 12-18" of insulation in the attic ceiling. Tyro

I realize this is an older thread but for anyone else thinking of building a new home, as an Architect I agree with this statement. I personally wouldn't want 2x4 walls and you likely need to verify if you can even use 2x4 studs with the Energy Codes in your jurisdiction. Washington State has pretty stringent requirements and off the top of my head I couldn't tell you if they allow 2x4 construction.

I am redoing my siding this next year on my current home, and I plan on adding the foam wrapper Tyro discussed above.

[Tyro]

Regarding heat loss through the studs, we were also playing around with 2x4 studs between 2x6 plates, alternating between inside & outside of the wall. I haven't seen/heard of this lately (and didn't find it on a quick search), so I don't know if it caught on or was abandoned...
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Tyro

[IBWino]

Quote:

Originally Posted by Tyro Regarding heat loss through the studs, we were also playing around with 2x4 studs between 2x6 plates, alternating between inside & outside of the wall. I haven't seen/heard of this lately (and didn't find it on a quick search), so I don't know if it caught on or was abandoned... _________________________________ xxxxx[]xxxxxxxxxxxx[] ____________[]____________[]_____ Tyro

That is supposed to be good for noise suppression, especially with interior walls between adjacent rooms.

[ERD50]

Yes, an old thread, but just as timely now as when started, and in 1976...

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Originally Posted by Tyro I happen to have a degree in Construction as well, with specialization in solar/alternate energy systems (albeit class of '76). .... I agree most heat loss occurs through ceilings, windows, & doors, but IMO that is no reason to cut corners on wall construction. Tyro

I'm curious about the above. I mean, don't you hit a diminishing returns with the wall insulation? Oh wait - just re-read my comments in post #15 of this thread from 2008!

http://www.early-retirement.org/foru...tml#post756322

Quote:

Originally Posted by Tyro Regarding heat loss through the studs, we were also playing around with 2x4 studs between 2x6 plates, alternating between inside & outside of the wall. I haven't seen/heard of this lately (and didn't find it on a quick search), so I don't know if it caught on or was abandoned... _________________________________ xxxxx[]xxxxxxxxxxxx[] ____________[]____________[]_____ Tyro

I like the concept of less bridging (incredible how much there is in the exterior corners), you could even 'snake' electrical through the gaps. But you need 24" spacing to hang drywall (or maybe not - if they go horizontal? Just some multiple of 8 or 10 or 12'? Not sure about code limits on that staggered wall.). But if you need 24", that is effectively a 2x4 every 12" rather than the usual 16", or 2x6 every 24". So it is going to be more material than 2x6 24" OC.

So looking back at my 2008 post, even if this gives ~ 10% better overall wall performance, I'll just guess walls are less than half the loss, you need to determine if ~ 5% fuel savings is worth the cost.

I have a largish home, probably sub-par insulation, in Northern IL with heating and cooling required. And not sighted well - summer sun kills us. Yet, my total utility costs were just under $2000, and only a portion of that is for heat/cooling. Twenty YO furnace (~85-88% eff?), older A/C. In fact, I just looked at my spreadsheet with 2012 annual bills, and if I use the lowest month each for gas & electric in the non heat/cooling season for each as a baseline, it appears only 1/3 was for heat/cooling (we had a mild winter, but a long hot summer - AC was on much more than normal).

So even a generous 10% fuel savings based on half the $2000 rather than the third of it is ~ $100/year. If it costs more than 25x to get that $100 savings, wouldn't the $2,500 plus be better in my retirement account? I doubt a buyer would compensate me for what's in my walls, and could I prove $100 annual savings? I'd rather have the $2,500 (and I suspect it would cost MUCH more to add those features to new construction), and pull an inflation adjusted $100 plus from that.

I'm stingy with the thermostat, dressing for the season goes a long way towards comfort w/o expending energy - and donning a sweater/socks/slippers or going in shorts/t-shirt costs near nothing and is not a sacrifice.

All this needs a good financial scrub - maybe you need to get the house tight enough and efficient enough that you can downsize the furnace and A/C to make the numbers work? But at that point, you need an air exchange unit, and those are not cheap. Passive solar, overhangs, etc can help and maybe not much $ if planned for (I know proper sized/oriented overhangs can make a big difference in my latitude/climate, and look good IMO). But again, even if I spent $1000 on heat/cool, and could cut it in half, that's would need to add less than ~ $13,000 to the construction costs, relative to my current bare minimum construction. Can $13,000 cut a heat/cool bill in half on a largish house? I think that would be challenging.

-ERD50