Posted By Animag771 on 18 May 2017 06:37 PM
Well I just have to say WOW, I am sincerely sorry to the original poster of this thread. I had no idea that me posting what I had planned for my own (450sqft) house, would derail this thread so far. As somebody mentioned, neither of us provided context to which climate zones we were in. Idk about the Loghomebuilder, but I'm in zone 3 (near Ft. Worth, TX) and as for the comments on the costs associated with a lot of my plans, I suppose I should have mentioned that I am building the house by hand and the only labor I will be paying for is to install the standing seam roof. So any additional time or labor involved in my (apparently complicated) plan will be free. The main reasoning for wanting to do 2" of closed cell foam was the mostly for air sealing to create a very tightly built house. There may be other (cheaper/easier) ways of doing this and I probably just don't know of them. Again... Sorry for the derail.

<!--[if gte mso 9]> No need to apologize. It’s not your fault these “green” sites are plagued with BS & sales hype. As you see clearly posted above Dana insist you have a thermal bride w/o even knowing what your temperature differences are, basics, and greentea or tree or whatever agrees w/him that your spray foam is over priced w/o even knowing what you are paying for in materials and labor in FW. Now you know, be careful taking advice off the bogus internet green sites from these clowns.

I’m not a fan of SPF/CC or OC due to all the toxic reactive issues all over the internet. Even though it air seals well.

You have a challenging market place there with labor & housing shortages, incomes that don’t support new construction, good idea DIY if you have all those skillsets to produce quality. I’m trying to come up with a design using alternate materials that works in locations like DFW, under $250K at HOA SF mins where the biggest challenges and demands are. I doubt energy efficiency nor high performance fits that model, an extreme challenge unless I find some low cost materials, build cost reductions. Perhaps it all cleans up by the time you sell, if you sell.

http://www.metrostudy.com/dallas-fo...ard-shift/

Paige is a good source of info, nice to talk to. I’m also looking at Austin. Teresa @ “Green Money Lending” has some good perm financing if needed based on HERs score, etc.

Your biggest risk as shown in the test I posted is the outer layers vapor locking & cladding MMC, & ROI. Cladding with high MMC capacities & sortion rate(intake/exhaust drying speeds) will be good. A ventilation gap like the one I show in my models would be good preservation. There are some guidelines in this doc, table 2.

https://buildingscience.com/documents/building-science-insights-newsletters/bsi-089-wufi%E2%80%94barking-wrong-tree

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Posted By Animag771 on 18 May 2017 06:37 PM
Well I just have to say WOW, I am sincerely sorry to the original poster of this thread. I had no idea that me posting what I had planned for my own (450sqft) house, would derail this thread so far. As somebody mentioned, neither of us provided context to which climate zones we were in. Idk about the Loghomebuilder, but I'm in zone 3 (near Ft. Worth, TX) and as for the comments on the costs associated with a lot of my plans, I suppose I should have mentioned that I am building the house by hand and the only labor I will be paying for is to install the standing seam roof. So any additional time or labor involved in my (apparently complicated) plan will be free. The main reasoning for wanting to do 2" of closed cell foam was the mostly for air sealing to create a very tightly built house. There may be other (cheaper/easier) ways of doing this and I probably just don't know of them. Again... Sorry for the derail.

In Austin (where Net Zero Ready is now code minimum) there are several builders getting there with 2x6/R20, no continuous insulation. With a well simulate design you can probably get there too, but with something as small a 450' house it may mean a shed roof rather than a gable to mount the array, if that's a design goal. Fort Worth has more heating degree days than Austin, but the expense of more PV to handle the modestly higher energy use difference in your climate is probably going to come in less than a lot of building envelope upgrades. Running BeOpt for tweaking the design would be useful for making those trade offs.

Spray foam only air seals the cavities, not doubled up top plates, or between bottom plates & subfloors. For a lot less money it can all be done with polyurethane caulk, caulking the sheathing to the framing inside each stud bay, making the sheathing the primary air barrier. Open cell foam may be cheaper than dense-packed (or even damp sprayed) cellulose in your market, but cellulose (damp sprayed or dense packed) and another case of PU caulk is still greener. If you're in a termite zone there is some additional rationale for going with a high-borate cellulose.

Take a peek at the Zone 3 row Table 2, p3 of this document:

https://buildingscience.com/sites/default/files/migrate/pdf/BA-1005_High%20R-Value_Walls_Case_Study.pdf

These are the approximate "whole-assembly-R" values it took to hit Net Zero back in 2009, when residential PV was 12-15% efficiency (and more than 2x the cost) of today's 18-20% efficiency PV. At that time HSPF11 and SEER 15 were considered pretty good for ductless mini-split heat pumps, but the bar has moved to HSPF 13+ and SEER 20+ (though high SEER systems won't always cut it for latent load in your climate.) Between those two technology improvements it's getting easier & cheaper to hit Net Zero.

At 24" o.c. stud spacing with some attention to advanced framing techniques (for sub 20% framing fraction) a 2x6 / R20 wall comes in at about the recommended R15 whole-wall for climate zone 2, and that's probably going to be good enough for current technology PV & heat pumps, as long as the rest of it is fully up to snuff. You can drop to R4 for the sub-slab insulation rather than the recommended R5- an inch of Type-II EPS works for stem-wall designs, grade beam foundations would require engineering input. If pentane blown rigid foam on the walls doesn't transgress your verditude sensibilities, an inch of continuous foil faced polyiso brings it up to the R20-ish range recommended for zone 3. (Low density 1" foil faced polyiso is less than half the polymer per square foot of your original 2" closed cell spray solution, and less than 0.5% of the blowing-agent damage.)

Posted By greentree on 18 May 2017 02:51 PM
First off I agree with your first reply regarding consumers, banks, the industry, where we differ is you are trying to operate outside those constraints and I am operating within. I dont go balls out with this stuff because it doesnt offer me a return and I would go broke. Im a fan of the "pretty good house", that's scaleable and realistic.

I'll help you out with your example plan, to make your abomination a bit more saleable I would suggest:

1. a 4/12 shed porch roof between the master and garage with a standing seam roof to help out your curb appeal and break up your mass of shingle.
2. Change the front gables cladding to shake or board and batten, people eat that up.
3. Flip your main bath fixtures to share a common plumbing wall, especially since your on a slab, that will certainly bring down your rough in costs Im sure you have in exactimate (which is an insurance restoration estimating platform, there are better options for building)
4. Flip the master closet so the bath door comes into the vanity, no one wants to open a door in front of a toilet, ever. Also buys you room for a shower across the bath, your current mod shower isnt desireable.
5. I cant help you with you choking the kitchen off from the living area or the huge amount of wasted space behind the couch, you lost the wife on that one, and no laundry or tiny laundry, again wife hates it. I would move the back mid bedroom behind the garage, label it as an optional study/bedroom and now you have an open concept that 99% of people want.

You can draw trusses in chief, it looks like you tried to make energy heel by raising the exterior wall height, you need to spec energy heel in your roof dialog. After you draw your exteriors and before you draw interior set your heights. You can vault certain rooms later, you dont need to vault the whole building right away then the gables show up like they do, your layers can get messy, unless your using Chief strictly for rendering which is a colossal waste, sketchup would be more "cost effective" for that. Which begs the questions, where do your prints come from?

My design/bim process is also in chief (with accurate build ready models, not just renders like you do) and includes full framing plans, cabinets/cubbies/built ins, full electrical/structured and full lighting plan allowing us to design mechanical layouts including all exterior penetrations ahead of time, correct or solve conflicts and verified in a preconstruction meeting with a full size set. I draw the prints, the extra time is worth less headaches during the build process and any contract specification issues, and I can draw anywhere, including on the boat or in the ice shack or on my sweet matress with the adjustable base. The goal is no questions from subs once we start, and the as built looks just like the renders, down to color. If Im not framing it I have done full labeled wall framing sectionals to remove as much extra framing members as possible, however its faster and less time intensive if the framers plate the building and Ill come and mark the layout versus having a ton of D size sheets to manage.

I see what you are trying to do, but if you moved to my area and tried that here the deck would be stacked against you big time, I see you as ahead of your time (compliment) but snarky (diss) and I dont know about you but Im in this business to make money, Id much rather be burning gas on my boat than on a construction site (I like both, but one better) any day of the week so its a means to an end.

Post some more of your plans, I like to criticize them.

Went back and looked at this more closely, you're right I should figure a way to create an open great room. Local realtors said it would sell so I called it good. 1525 SF is a challenge for 3 bed/2bath, sets back, easements, drainage, lot size constraints. I didn't think ppl want to walk in the door look see a messy kitchen thats why the kitchen and 3rd bedroom aren't swapped. I have others that are very open all though the 10' walls and vaults ( bedrooms have ceilings) help but suck energy, so do open belows people want. Energy efficient designs are a hard sell, so is ROI. I don't do the estimating, we do lots of insurance work too where we get best profits....Forgot what our estimator uses he hard to fit in the budget. I think we do alot in Accylynx too.

Just did a custom client designed I fixed. Provided net zero estimates over competition. Insulation cost @ 12% of total w/ high cost better performing Roxul, ductless MS HVAC w/ ducted HRV 3% higher than mainstream FA system. Total above market cost 15%, (thats why there usually is no room for more roof porches, metal, etc, a simple square box envelope & roof is best to leave room for insulation/HVAC). Once the client seen mainstream cost they backed out, forget net-zero with low utility bills that can be cash flowed, appraised or help qualify home or buyer a no-go. Without it don't make sense, I don't care what any article on the internet says. Solar sense most locations forget it no way, TX included. The only way to justify a start-up spec/sales model/market center thats sits on the market at least a years burning interest are big losses in hopes of establish a profitable market & comps, the big builders with cash to burn can do in 1-2 zees.

I regret choosing CA, didn't know better at the time. It sucks for MEP, BIMS. I'm moving to CATIA that can do the take-offs, MEP, build sims better. I want to eliminate drafting time do it all in 3D where all annotation and dims are on a plane.

Check out this video: https://www.youtube.com/watch?v=42QxYerPMZw

I tried to get CA users on their forums on this train, big mistake got my arse kicked, lol!

I consulted these guys a while but they ran out of budget. As far as I know they are further along than anyone in AEC. Getting the right trades on board won't be simple but, I have been doing it for over two decades in manufacturing environments (my main clients btw) that are more structured of course. Theres a lot more to the benes, cost reductions, I could right a book.

Anyway, I can tell you actually do design-build better to listen to than some these other "Green Advisors" damaging this industry with BS they try and profit from leaving behind homeowners with big fat loans, lost cash, maintenance bills. I'm going to rebuild all my specs in CATIA with the MEP in 3D so I can see what the hecks going on easy . Thanks for the advice I just like giving u crap :)