MEMPHIS builds a house

[MEMPHIS91]

So I never thought I would say this but we now have plans on moving, the current location/house/stress is not what we want. So we have plans on moving to another county (this one is getting way to strict in all the wrong ways). Looking at a 1,500-1,800 square foot 3 bed 2 bath house with a 10x12 (not heated and cooled, just insulated) basement/root cellar. I want it to be as efficient as money will allow, I will doing most of the work myself as NO one in the area knows how to build a tight super insulated house.

Thoughts so are:
-2x6 exterior walls on 24" centers with 1 of spray foam and the rest filled with fiberglass or cellulose

-3/4 ridge foam wrapped, with 1/2 osb sheeting on top and then wrapped in a good moisture barrier/air seal

-roof with 3/4 ridge foam and vertical 1x4's strips to allow the silver tin roof to vent.

-vented brick exterior

-dense packed cellulose in the ceiling to about R40

-insulated slab floors (though I am finding places saying uninsulated is better)

-vinyl 9mm fake wood tung and groove flooring

-5 total mini splits 2 of these for where we will be most of the time Gree Crown 9 000 BTU Ductless Mini Split System Remote 25' Lineset 208 230V | eBay and a set of these for everywhere else 27000 BTU Tri Zone Ductless Mini Split Air Conditioner and Heat Pump SEER 23 | eBay

-Looking at this hrv Panasonic FV-04VE1 WhisperComfort Ventilator, ERV

-There will be a wood fireplace for back up heat

-all led lighting wired 12v

-all dc ceiling fans (each bed room and one in the great room)

-heat pump water heater in the basement/root cellar

-good at least triple pane windows with double low e coatings

My goal is to make a house that isn't out of the park expensive but can still out perform 90% of houses built today.

I think I am set on no geothermal for the main house, I might put in tubes in the floor just in case I want to build a DIY geothermal heated floor for the main rooms of the house.

I am doing tons of research into how to position the house for best solar

My cooling days are more than my heating so im looking into how and where to add radiant barriers.

Opinion on if a should build in a way to prevent thermal bridging? Or is it not as big a deal down south?

Any tips, tricks, or links would be awesome. This is going to turn into a long long thread as I post building pictures and as always a step by step over view.

Thanks guys and Shalom

[natethebrown]

I would highly recommend you go with non-wood SIPs (Structurally Insulated Panels). May cost more for the materials but time, ease, and insulation value is not beatable.

[MEMPHIS91]

natethebrown, I am looking into them now, why non wood?

https://www.youtube.com/watch?v=QhOYlHG_aAc

[stevehull]

Don't obsess on PV solar roof orientation. So long as a roof area is within 20 degrees of true south each direction, this still gives you 90-95% of true south solar power.

Mistake on triple pane. In your southern climate, you don't need it in the winter - money spent here is a FAR too long payback. Double pane is certainly enough - but buy good ones, not the locally built vinyl clad cheepos. But you DO need to pay attention to summer overhangs on east, west and southern windows to prevent solar gain (maybe this is where you meant orientation).

In your area, do NOT insulate slab as you need to bleed off heat in summer. Your ground temps are just not that cold in Mississippi.

Outside air moisture and interior humidity are your enemy. Put your dryer in a room with outside air inlet and seal it off with good closing (sealed) door. A dryer pushes some 500-600 CFM per minute out of the house and conditioned air pushed out means that air (humid/moist and hot) MUST come in as house is now a vacuum.

Two ERVs are a necessity with a tight home of this size. The ones you are looking at are great in bathrooms to vent moisture 24x7 and total also provide about 40 CFM total (low speed). When bathroom/shower is in use (DPDT switch to bathroom light), then HRV goes into high fan speed mode (total 80 cfm).

I would still do geothermal for ducted AC . . . . an open loop system. You need to put in a well anyway. That many minisplits gets you into expensive territory. I have recently bought from Ingrams and they have a very nice three ton GTHP for about $3100. Forget the thermal heated floors - you just do not get that cold to justify that cost.

I would do SIPS for roof as you get everything for not a lot of $ and will be installed in one day (roof decking, insulation, interior trusses, R40 foam and inside OSB). SIPS with 8 inch foam (R40) are easily available. You can get 12 inch, but your local conditions don't merit. You can span up to 40 feet with SIPS. Makes interior layout easy with no load bearing walls needed.

Infiltration is your enemy - not heat or cold. Build yourself a temporary blower door (or window) with an old HVAC squirrel cage blower and simple water manometer. I use dry ice for "smoke" to detect leaks.

If you are in a rural area, build a pond (discharge water from open loop geo unit into this) as this markedly lowers your home insurance. Home insurance goes WAY up in rural areas with volunteer fire departments. You will also get a discount for metal roof (good idea). A fire pumper can dip suction hose into pond. Pond got me a 30% discount on my home insurance . . .

Do you really mean "as efficient as money will allow"?

Why a fireplace? This is a true energy waster. Put in a good wood burning stove that has opening (and closing doors). You can see fire if you want to, but can close it up for more efficient use. - but make it small (24 - 36 KBTU/hr) as it will otherwise overheat the house.

Mazel tov!


Steve

[natethebrown]

Originally Posted by MEMPHIS91

natethebrown, I am looking into them now, why non wood?

So you don't have to fool with insects or molds, and they are probably lighter with better insulation value. The negative is you have to now use screws to attach to the steel.

Here are some old pictures of my dad's addition (his addition is about 95% complete now):







You can see each SIP is about 4'x10'x~1' thick and is light enough for two people to handle. Any ways, if you decide on wood SIPs, no problem, I just believe the "standard" stick frame home is out of date and so low tech compared to what building technology we have now.

[MEMPHIS91]

Originally Posted by stevehull

Don't obsess on PV solar roof orientation. So long as a roof area is within 20 degrees of true south each direction, this still gives you 90-95% of true south solar power. I forgot to mention that we are going with a single pitch/mono pitch roof so I will have tons of room for solar.

Mistake on triple pane. In your southern climate, you don't need it in the winter - money spent here is a FAR too long payback. Double pane is certainly enough - but buy good ones, not the locally built vinyl clad cheepos. But you DO need to pay attention to summer overhangs on east, west and southern windows to prevent solar gain (maybe this is where you meant orientation). Awesome to know on the windows thank you, and yes that is what I meant.

In your area, do NOT insulate slab as you need to bleed off heat in summer. Your ground temps are just not that cold in Mississippi. 10/4, that saves more money.

Outside air moisture and interior humidity are your enemy. Put your dryer in a room with outside air inlet and seal it off with good closing (sealed) door. A dryer pushes some 500-600 CFM per minute out of the house and conditioned air pushed out means that air (humid/moist and hot) MUST come in as house is now a vacuum. 10/4, I was thinking about something like that as well

Two ERVs are a necessity with a tight home of this size. The ones you are looking at are great in bathrooms to vent moisture 24x7 and total also provide about 40 CFM total (low speed). When bathroom/shower is in use (DPDT switch to bathroom light), then HRV goes into high fan speed mode (total 80 cfm). I'll plan on 2 Erv's

I would still do geothermal for ducted AC . . . . an open loop system. You need to put in a well anyway. That many minisplits gets you into expensive territory. I have recently bought from Ingrams and they have a very nice three ton GTHP for about $3100. Forget the thermal heated floors - you just do not get that cold to justify that cost. I have no attic space with a monopitch roof, and being on a slab I can't go through the floor for a ducted system, these mini splits are pretty amazing and I think we save money on Install vs the geothermal. The only well I plan to have is a solar powered well pumping into a small water tower with a booster pump if needed.

I would do SIPS for roof as you get everything for not a lot of $ and will be installed in one day (roof decking, insulation, interior trusses, R40 foam and inside OSB). SIPS with 8 inch foam (R40) are easily available. You can get 12 inch, but your local conditions don't merit. You can span up to 40 feet with SIPS. Makes interior layout easy with no load bearing walls needed. The sips I am looking at are claiming R7 per inch, so I'm thinking of using their 4.5" on the walls and 8" on the ceiling/roof. Polyurethane Structural Insulated Panels | Energy Efficient Eco Panels SIPs - About Eco-Panels

Infiltration is your enemy - not heat or cold. Build yourself a temporary blower door (or window) with an old HVAC squirrel cage blower and simple water manometer. I use dry ice for "smoke" to detect leaks. I got a huge 4,000 cfm greenhouse fan

If you are in a rural area, build a pond (discharge water from open loop geo unit into this) as this markedly lowers your home insurance. Home insurance goes WAY up in rural areas with volunteer fire departments. You will also get a discount for metal roof (good idea). A fire pumper can dip suction hose into pond. Pond got me a 30% discount on my home insurance . . . I'm a fireman, I am looking into a small pond, but I think if my water tower can hold 1,500 gallons I can get away with that as well.

Do you really mean "as efficient as money will allow"? Yes

Why a fireplace? This is a true energy waster. Put in a good wood burning stove that has opening (and closing doors). You can see fire if you want to, but can close it up for more efficient use. - but make it small (24 - 36 KBTU/hr) as it will otherwise overheat the house. I should I have been more clear, wood burning insert is the plan, we like the look of the brick and the fire.

Mazel tov! Thanks


Steve

Thanks so much for your help, I have written down your ideas and they will go into planning

[MEMPHIS91]

natethebrown, Yes the more I look into SIPs will play some roll in the building, thanks for the awesome idea. I will look into the cost comparison with wood/non wood. Good pictures as well.

[stevehull]

I have successfully used sub-slab supply ducting (glued PVC) and as a side benefit it really heated up the concrete slab floors in the winter (dogs loved it!).

The old metal ducts clearly don't work (they always rust out), but the glued 8 inch long tube type PVC ducts are absolutely watertight.

Not hard to do and now the supply ducts are completely out of the way - and there are NO air leaks. You can do a common air return and/or return "jump" ducts into bedrooms and other closed off spaces.

Your RFD and/or insurance carrier can tell you the amount of water that qualifies for the discount. In my case it had to be a 1/4 acre pond at least an average of four feet deep (total of one acre foot) and had to be there all year round.

Be realistic and do what you can do. Hire out tedious stuff as otherwise you will have a two year build phase or never quite have anything done. Remember that construction loans are only for 365 days.

All is simple, but there is an advantage to getting pros to come in to quickly get you dried in. With SIPS, this is no more than two weeks.

Also, hire out the brickwork - they are just so damn fast and perfect.

Have fun!

Steve

[MEMPHIS91]

Originally Posted by stevehull

I have successfully used sub-slab supply ducting (glued PVC) and as a side benefit it really heated up the floors in the winter (dogs loved it!). Wow, never thought of that.

The old metal ducts clearly don't work, but the glued 8 inch long tube PVC ducts are absolutely watertight.

Not hard to do and now the supply ducts are completely out of the way. You can do a common air return and/or return "jump" ducts into bedrooms and other closed off spaces.

Your RFD and/or insurance carrier can tell you the amount of water that qualifies for the discount. In my case it had to be a 1/4 acre pond at least an average of four feet deep. Not hard to do when I have a 240D excavator I can use.

Be realistic and do what you can do. Hire out tedious stuff as otherwise you will have a two year build phase or never quite have anything done. Remember that construction loans are only for 365 days. Yes from start to finish a year is what I was thinking, but maybe faster if the money comes in. I'm hoping to build as I can with no loan, but that depends on how the next 2 months go.

All is simple, but there is an advantage to getting pros to come in to quickly get you dried in. With SIPS, this is no more than two weeks.

Also, hire out the brickwork - they are just so damn fast and perfect.
Amein to that! I can draw a straight line, much less lay brick. lol
Have fun!

Steve

Right now I have a 2,400 sq ft home that is terribly built and has more problems than I can name, with a 10 seer OLD heat pump. My bills never hit over $120, is a geothermal system really going to save me THAT much money? I like the idea if one unit goes down I still have 4 others able to do the job. BUT if we are talking big big savings then it might be worth it.

[stevehull]

A GTHP does several things. First the summer SEER is 35+ and you get free hot water from the desuperheater. The winter heating is easy as the COP is 4+ and you get hot water as well, but not as much as in the summer.

Ingrims is the key. A 36 K BTU/hr GTHP for $3400! Misc supply PVC is another $300 or so and you can glue this together. Then some supply boots put in before you do the slab. This is easy work.

Two (2) Stage Geothermal Heat Pump Buy Goodman Heat Pump | Geothermal Heat Pumps | Goodman Air Conditioner

The minisplits are great, but they don't seem to last that long . . . . .

Some of my GTHPs have been going since 1991 with no fixing at all (except air filters).


Steve