Hey everyone, first time posting on here. The quick rundown is that I’m planning on building a house for my young family by myself (as much as possible). Yes, I know it will be A LOT of hard work, but I am ready for it.
I’ve done tons of research and that will continue throughout the whole process. I have the “final” design done and would like some feedback on some of my thoughts and plans. I just got done clicking through 200 pages in the Construction Techniques and figured that gives me the right to post my own. 🙂
32×64 Ranch style with full finished basement with wood walls and attached 40×44 heated garage. Here is the list of my details:
2×6 exterior walls
9′ studs 24″oc
double bottom plate (so I can square/seal/fasten the bottom plate to the concrete and then lift the walls on top of the first one)
single top plate
7/16″ Zip (4×10 placed vertically)
2×12 rim joist
32’x12″ floor truss (with 2×6 support wall @ 16′)
7/16″ Zip (4×10 placed vertically)
Advantech subfloor
2x6x9 24″oc walls with single bottom and top plates
4/12 roof trusses 24″oc
5/8″ ZipÂ
4″ of closed cell foam
vinyl siding
shingles
Radiant floor heat in the basement (haven’t decided if it will be 1 zone or zoned according to the bedrooms/bathroom) (garage will be a separate zone, but probably the same boiler)
HVAC in floor trusses for main floor heat (if its even needed) and whole house A/C.
Interior:
5/8″ drywall everywhere except the Rec Room in the basement will be painted OSB (think kids that like to play hockey/soccer/baseball/football)
Garage:
2×6 12 or 14′ studs 24″oc
7/16″ Zip
4/12 40′ roof trusses 24″oc
5/8″ Zip
2-10×10 doors
4″ CC foam
My thinking is that my house walls will be able to be covered with 1 Zip panel per floor? Am I correct with my design/math?Â
I tried to design so that the windows are 4×4 and the spacing between openings (doors/windows) are on 4 foot sections so I don’t have much for cutouts. I have many other details that I’ve tried to think through, but I’ll leave it at this for now. Will it be structurally sound? Efficient material-wise? Efficient insulation-wise? I am located in northern ND where the current temp is -24*F and the real feel is -45*F.Â
If you made it to the end. Thanks for hanging in there. Looking forward to some honest feedback.Â
Rylan
Replies
What kind of basement walls are you planning? and how high?
since it looks like basement bedrooms, you are, I assume familiar with egress requirements. a few of the rooms seem to be missing windows in the basement.
why the rim joist? solid lumber 2x12 does not match 12 inch truss. with a truss floor, why not let them also engineer the end treatment? are you coordinating truss specification with the HVAC runs?
With a truss floor, why have a rim joist at all? trusses can be mounted to the inside of the basement walls, or specify top mount trusses, and integrate your first bottom plate with the top web of the trusses.
I think the ten foot sheathing is not a match for your other specifications.
nine foot stud with three layers of 2x6 and 12 inch rim joist will adds up to 10 ft 4.5 inches.
Basement exterior walls will be 2x6x9, interior walls will be 2x4x9 (except the middle support wall will be 2x6x9), the 3 bedrooms have egress windows. The basement has 3 bedrooms, 1 bathroom, large rec room, open table game area, media room, and mechanical room.
I was planning to have trusses that sit on the basement walls (so I can still have a full 9' ceiling in the basement). Doesn't there need to be a rim joist? Or am I just supposed to use the sheathing to cover the truss ends? What is the difference in the solid 2x12 and the 12" truss? I figured I can place the furnace in the mechanical room to match up the straight runs with the trusses and use flexible ducting when needed.
My thinking on the 10' sheathing was the whole wall (basement floor to eaves) would look like this: 3" of 2x6 bottom plate, 9' stud (~105"), 3" of 2x6 top plate, 12" truss, 1.5" of 2x6 bottom plate, 9' stud (~105"), 3" of 2x6. That's 232.5" and two 10' sheets should be 240", right? The plan would be for the two sheets to meet in the middle of the floor truss (rim joist) so that both levels are tied together. Is my thinking still wrong? Does the 4/12 common roof truss add anything? That should sit right on the top plate, right?
Maybe I should've specified in my first post, but I thought it was getting long. I don't have much construction experience, besides framing up garden sheds. But I think I do have the smarts and the drive to accomplish this. And I am very much willing to learn as much as possible before, during, and after the project is over. I also have 4 cousins that all live close by with construction as their occupation and 2 BIL's in the construction/engineering fields. Everyone would be willing to answer questions and help out if needed, but I still want to gain insight from anyone willing to share.
I did not see at first you were going to put in a PWF for the basement walls.
Where are you going to get the floor trusses from? They should have an end treatment that complements the truss design. My point is that a 12 inch tall truss is 12 inches, a 2x12 is more like 11 1/4.
See: https://www.mitek-us.com/products/Floor-Trusses/
roof truss will sit on top plate (and be secured as specified, clips are your friend when the wind blows)
is Zip system siding meant to be buried? Last time I looked, you needed treated plywood below ground level. I also thought that one benefit is that you can use a gravel product as the footing, instead of poured footings. (a slab, of course can be poured, you would likely want to use some insulated foam under the slab in your case)
do you have the location selected? an analysis of the soil structure is a good idea, to validate the strength the basement walls will need (and how thick the wall studs have to be)
It is a good idea to consult with someone on the HVAC design, and see how air distribution will be accommodated before you specify the floor trusses.
I would be interested in where you found that closed cell foam gets an R value that is twice what it is. A quick look at the codes you were linked to shows there are separate requirements for R values and for air sealing.
I'll either get the floor trusses through menards or just the local lumberyard. I just thought a rim joist was necessary. If not, then great, less cost for me.
I think I remember reading that the Zip panels can be below grade, but I sent a message to the Huber Tech department just in case.
I do have a location, but I will probably dig down 2-4 feet and then haul in fill for the grading.
Even if the R value isn't technically doubled, with 2x6 walls, I'll still get a good 4" (R28). And IMO, not letting any air movement through it makes the insulation value worth more. Sort of like the R value doesn't need to work as hard since it's only combatting temperature instead of temp + wind. (At least that's how my mind works it out...I may be wrong)
When you say basement walls are 2x6 , is this a Permanent Wood Foundation?
How deep are the footings for this house? What is the frost line in your area?
Is the slab for the garage at the same level as the main floor?
I don't see any stairway in the plans.
Entrance ways: A foyer at the main entrance with a closet and bench space to help with winter boots and things is always a good idea in cold climates. An interior door to the foyer will also help minimize heat loss.
Is there a mud room (secondary entrance ) for the kids to keep their outdoor stuff?
If you have radiant heat for the basement, why not the whole house.
Have you read all the relevant building code info?https://www.communityservices.nd.gov/buildingcode/
You need more insulation.
Sorry, yes I mean a permanent wood foundation. I believe the frost line is 4 feet. I will be subbing out the concrete work, so they will build the footings/slab according to code or better.
The garage slab will be 1-2' lower than the main floor level. There are basement steps in the house, they just aren't in the picture I uploaded. It will be 4' wide and attached to the 2x6 center support wall in the basement.
The foyer entrance will be mainly for guests and non winter-time coming and going. The main entrance my family and kids will use will be from the garage. There will be plenty of storage for boots and everything in the garage before entering the house.
I live in a county that doesn't enforce codes, but I will be building it to meet or surpass. Why isn't 4 inches of closed cell enough? We've been told that 1 inch of closed cell is R7, but since there is no air movement through it, then it can be doubled to R14. So 4" should be R56.
Basically, I want to be able to control the AC room by room, so there will be ducting to each room anyways. If the floor heat/insulation is good enough to keep both levels warm, then I just won't run the furnace. If I want a little extra warmth, I'll turn it on and control it with the vents.
Here are the plans with the furniture more or less in place.
Thanks for the replies so far!
For the foam and walls, as I mentioned in a previous post, where did you see that you can double the already "in some cases" R value of 7 per inch?
if you are thinking of spraying this yourself, be aware that the feedstock for blown foam is toxic, and you will be well advised to wear proper breathing protection and let it outgas for as long as possible before you move your young family in.
https://archive.epa.gov/epa/saferchoice/potential-chemical-exposures-spray-polyurethane-foam.html
and keep in mind that this is only the foam R value, applied inside a wall cavity, the wall studs have less R value, so the structure ends up with a lower R value overall.
If you want an idea of what the actual heat loss of your home will be, you can run the numbers.
I used this ten years ago when looking at options for my house, based on a model of the actual heat loss(or gain)
https://www.hvaccomputer.com/hvac/tofc2.asp the interface is a little dated, but I did not see a better option when I looked a while ago.
when selecting insulation and sealing for your house, the comfort and cost over time is a worthy subject of your attention. Another input will be the source of your heating fuel.
I will be spraying it myself. Like I said, my dad owns a foaming setup that we have been using for 5 years or so. We foamed our 100x150 steel building (walls + ceiling) and plenty of other jobs we've picked up. That shop is sealed so tight, when we try to close the 48' hydraulic door, we need to open the garage door to let the air out.
As far as the studs having less R value, that's why I was liking the idea with the advanced framing of 24"oc instead of 16"oc and using header hangers instead of so many jack studs in the openings.
Thanks for the link! I tried using it, but it doesn't seem to tell me anything? Maybe I'm not using it right. All I do know is that I trust and believe in closed cell spray foam. I've sprayed many garden sheds, crawl spaces, garages, additions, dog houses, sauna rooms....it is strong, it seals every crack/hole/seam, and IMO it insulates better per inch than anything else. I sprayed my BIL's small cheap tin shed that he uses for a dog/cat house and he can keep that thing at 50*F with a small space heater all winter long. And we haven't seen anything over -5*F for over a week!
I also have researched/read/watched a ton of stuff about the Zip System and again...IMO, I believe that is a superior system to the house wrap stuff. If I'm wrong in believing that, then I will accept the carnage that comes with it, knowing that I'm not the only one who fell for it. LOL
The house we are renting now has electric baseboard heaters and there is ice on the INSIDE of the windows. The floors around the exterior walls are COLD and I can usually feel a literal draft when I'm sitting on the couch that is beneath a window. I highly doubt any of that would be true on the house I'm planning. (yes, I know part of that are the extremely poor windows in this rental house)
Sorry for the book...haha. I just want to ensure that it's known that I won't settle for mediocre.
Book is fine.
not sure which link you said did not work.
the EPA link is for your awareness. since you have the equipment, hopefully you also have breathing protection to use. I know the person who ran the EPA study, and the advice to at least let it breath before having kids live in the structure is good. The concern is that the feedstock is not good for you (if you have used it, you know what it smells like) and while in ideal cases, all the feedstock is converted, mixing will be imperfect, and some will be around for you to breath while spraying, and some in the foam after it sets.
The manual J software https://www.hvaccomputer.com/
is my advice for two purposes. first, you can run trades with different input data to see the effect of additional insulation on heat loss. with information on heating appliance efficiency and fuel cost, you can trade money now vs money later. (example is to see how much difference in fuel cost over ten or twenty years triple pane windows would save over double pane)
The other reason is to make sure you size the HVAC for the expected load. your local heating supply guy may want to sell you a bigger unit than you need, since the sale will have more profit for them. but bigger is not better. Air conditioning works best when it runs longer. (more time to remove excess humidity from mid-summer air)
Since you are a big spray foam fan, and understand the sealing properties, not sure the Zip system would be worth the expense. With closed cell spray foam, the air sealing will be taken care of. Depending on the siding you plan on, tyvek on the outside can be a good idea to keep liquid water off the siding and let what vapor does get there escape.
You can consider treated plywood below grade, and standard OSB above. You might want to use 4x8 sheets and install them horizontally. This will be easier to handle, and staggering the edges will provide better structural support than having every other stud be a vertical joint between panels.
What is the land like? is it sandy or heavy clay? is there some slope to it you can take advantage of to daylight perimeter drains?
What kind of fuel will you use for the heating?
Will you need well/septic?
The land would be about in the middle of those two, but closer to the sandy side. It'd be decent farmland if that helps at all. The fill dirt that I would haul in to grade would be more like gravel/sand. There isn't much slope so daylighting wouldn't work.
Heating will be electric. I will be digging in a new septic, since what is there is the old "daylight" system. There is a well that I will use for exterior garden hose stuff, but we will be hooking up to Rural Water for the house supply.
I think you need to check your structural calculations. The design specification for PWF is here: https://awc.org/codes-standards/publications/pwf-2015
The Southern Forest Products Association has a design guide using Southern Yellow Pine: https://members.southernpine.com/publications/download/526ec2d401ac9ad71d000222/400_PWF%20Manual%202001_LR.pdf
With the garage slab at ground, 2ft difference between garage and first floor, 12" floor truss and 9 ft basement ceiling, backfill on the basement is ~96"
Max backfill for #1 SYP 2x6 12" oc is 84"
There is nothing in the tables for 2x6 24"oc or fills above 84".
Floor trusses will also need to be sized for the compression load from the walls, and you will need shear clips at the truss to wall.
Do you have elevations of the house at the site you are considering?
Yeah, I'm having multiple quotes for materials and it's looking like my 24"oc won't work unless it's 2x8. I'm also getting a quote for the ICF basement foundation now.
The elevation plans are being worked on, but I don't have them yet.
I think you will like the ICF.
Look into foam boards for below the radiant basement slab too. On some good gravel for drainage. How will you run the electric radiant heat in the basement?
with electric heat, you will want to err on the higher side of R values. Will you put in a heat pump? Or at least a heat pump water heater?
Will you orient the house for solar on the roof?
Sounds like you will need a sump pump for sure.
I'm still on the fence about the ICF's. I can't decide which pro/con list I like better.
The radiant floor heat will be run by an electric boiler. I guess I haven't even checked into heat pumps. Or maybe I'm not even understanding the differences between the two.
No to the solar.
Some of the first research I did was sump pumps with backup systems. If I couldn't find one that I could trust then I wouldn't have even done a basement. So yeah, the sump pump will have a backup and maybe even a backup to the backup.
2" of foam is a good start.
We are planning a radiant concrete floor and will use the closed cell Spray foam. It will insulate as well as be the vapor barrier.
The radiant system on the foam with 4" of Concrete.
A couple of thoughts:
It sounds like you may be in climate zone 7 (northern ND) one of the coldest in the lower 48. It's hard to have too much insulation where you are - and going above what building code would indicate for that climate zone can still pay off. You might take a look at the "Pretty Good House" approach, which "goes above code until it stops making financial sense." For your area, they'd recommend R-40 walls (!) which sounds crazy, but there's been a lot of carefully thinking and number crunching by some pretty level-headed builders to come up with those recommendations.
Spray foam has its pros and cons (we used retrofitting our house) and it provides excellent air sealing, which is absolutely critical for your climate. But you really can't get higher than the measured r-value of 6.5 or 7 per inch. I've heard the "double r-value" claim may have come from a spray foam manufacturer comparing the performance of a spray foam insulated house with a leaky, batt insulated house having the same r-value in the stud cavities. So if you air sealed that batt insulated house to the same level of air tightness as the spray foam one, there would be no difference in heat loss and thermal performance.
You're on the right track when you recognize the better whole-wall r-value you're getting by advanced framing with 24" o.c. studs. There's an interesting article in FH in 2017 titled "Closed-Cell Foam Between Studs Is a Waste" which suggests a 2x6 wall with 5" of closed cell spray foam ends up with a whole-wall r-value of only R-15 due to heat loss (thermal bridging) through the wood framing. That article uses a 25% "framing factor" (% of wood, not insulated stud cavity, in the surface area of the wall) which might be framed with studs 16" o.c.. Going to 24" o.c. and your goal of reducing jack & trimmer studs helps some, but my hunch is you'd still have a framing factor of 15-20% and a significant amount of heat loss through your framing.
For the attic, consider using raised heel trusses to allow thicker insulation in the area above your exterior walls.
So, long story short... if you plan on being there for a while, consider more insulation, and try to prevent the heat loss from thermal bridging at your framing, which makes exterior continuous insulation such as mineral wool a really good idea. Exterior mineral wool also allows the wall to dry to the outside should any water work it's way into the assembly.
Hope that helps.
I understand about the leaky house with batt's vs the air tight spray foam house, but why wouldn't the air tightness have a positive effect on getting to the higher r-value? If it does, then in my mind, foaming 4" should prove to be better than batts with other forms of air sealing because it's an "all-in-one" solution. Plus it adds strength. I will still be doing what I can to limit the thermal bridging with the advanced framing. I will still be using really good windows.
I think I read that article (or maybe a similar one), and I was a little concerned until it got to the point of saying "...closed cell doesn't work as well. What we suggest using is what we sell....". With that all said, I still believe in CC foam.
I would really love to try the Zip R Sheathing, but I don't know if I can justify the cost/travel. The closest Zip dealer is 360 miles round trip.
Thanks for the comments!
Use the insulated maximum Huber insulated zip walls with proper air sealing.
I'll tell you how many panels I need if you're offering to send me them. ;)
I'm not a supplier but have used standard foam for years on the exterior to stop the thermal loss of the framing to the exterior. Huber's new product is 1 1/2 R-12 I think with air sealing tape. Remember 30% of the wall surface is framing with direct loss to the exterior. I diffidently recommend something below the slab and stone fill 2" of foam works well. Stops heat loss to the ground and the stone fill and concrete become a heat sink. This has worked well in our zone 5.
https://www.finehomebuilding.com/2017/07/10/closed-cell-foam-studs-waste
I think the main point of the article is cost to go to closed cell foam vs open cell foam. (and other comparisons)
since you plan to do the work, have the equipment, the cost to you will be only feedstock materials.
The discussion on thermal bridging of the studs is still a good thing to pay attention to.
with your environment and heat source it might be worth your while to look for an additional layer of insulation over the whole thing. rockwool panels with strapping could fit your house, from the basement walls above ground level to the top of the walls. I bet you could get the materials for $5k or so. (including straps and screws) The sound of those howling north winds would also be reduced.
foam board also could be looked at but there are vapor issues with more than one vapor barrier in the assembly.
what kind of siding do you have in mind?
Vinyl Siding will be used.
You brought up another point that I've been wondering about. If I'm set on CC foam (which I am) then would having such an tight seal via Zip System on the outside create problems for my framing? The ideal outcome is that the Zip System is perfect and won't allow any moisture through, but the big IF it would...the moisture only has the studs to go to and then it would take forever to dry out, which would most likely lead to problems.
Would I really be better and safer to just go with CC foam, regular osb/plywood, housewrap, vinyl siding?? Because then at least if moisture gets through the wrap and sheathing, at least it dry out faster?
The Zip coating, and housewrap (like Tyvek) are water resistant, and seal against free flow of air, yet allow water vapor to pass.
This last part is important, and why you would use one of them instead of slapping 6 mil plastic film around the outside of the sheathing. It needs to breathe.
http://www.northernheatpump.com/default.cfm
These folks are in MN and make heat pump heating systems.
electric resistance heat (like an electric boiler) converts electrical energy you pay for into heat. At 100% efficiency, each kWh you pay for provides 3412 BTU.
annual home energy use is discussed using millions of BTUs (mmBTU)
another way to look at energy from electricity is that it takes 293 kWh per mmBTU
https://www.eia.gov/energyexplained/units-and-calculators/
annual home energy use is discussed using millions of BTUs (mmBTU)
the example in the EIA link above discusses two houses that need a bit under 70MMBTU per heating season.
https://www.eia.gov/energyexplained/units-and-calculators/energy-conversion-calculators.php
Manual J calculations provide a way to calculate how much heat energy you need, based on details of the specific house, and the temperatures inside and outside. You can scale the results to estimate annual heat needs based on the anticipated weather (degree days)
Natural gas at $10.01 per thousand cubic feet $9.65 per million Btu
Heating oil at $3.10 per gallon $22.56 per million Btu
Electricity at $0.10 per kWh would cost $29.30 per mmBTU
Of course, oil and gas get scaled by the efficiency of the furnace/boiler. you pay for input mmBTU and heat the house with output mmBTU
The whole point is to lead to heat pump discussions.
Heat pumps use electricity to move heat instead of generating it.
so you get up to 3 or 4 times the amount of heat from the electricity you pay for.
the catch is that you have to get the heat from someplace, and it takes more complicated equipment to move it.
for your house, you could dig wells, or trenches around the property and bury plastic pipes to gather heat from the ground.
If you look over ten years, a house that needs 70mmBTu per year would use 700 mmBTU.
700 mmBTU x 293 kWh/mmBTU x $0.10 per kWh
comes to $20,510 over ten years.
if a geothermal heat pump system costs you an extra $10,000 to install, but reduces the energy use by a factor of three, you would still be ahead by $4,000 over ten years, and later years would all be gravy.
the details matter a lot.
Heat pump water heaters for your house would make sense in the summer, when you pay for air conditioning. in HP mode, they take heat from the air (and from condensing moisture from the air) they come with resistance heat modes as a built in alternative, which would make sense when you are running the electric boiler.
Heat pumps move heat, while electric resistance heat generates heat.
http://www.northernheatpump.com/default.cfm
These folks sell systems and can provide cost/benefits of an alternative.
the bottom line is they cost more up front, but can pay off over time. In your location, a ground source could work, but would start with a bunch of wells or trenches to put the heat-gathering plastic pipe into.
You can also look at a heat pump water heater, which would make sense for you to run in heat pump mode in the cooling season. They make hot water by cooling and drying air in the basement (if that is where you install it), or by straight electric. (without cooling the air)
I was actually just watching some videos on the heat pump water heaters. I'll definitely be doing more research on them because they sound pretty nice.
I put one of the first GE heat pump water heaters in 11 years ago. I had seen earlier versions before that. The GE was fine, but my plumbing developed a bit of a drip, Where I had included Unions in the water feeds just above the heater, and the top feed of the cold and hot lines meant the drip ended on the refrigeration unit, which quit after ten years. Even so, it saved me money over that time in reduced electric bills. The heater is still working in straight electric mode. ( I paid $1800 for a 50 gallon. now they retail for around $1300 and up)
Recent designs have the cold and hot water connections on the side, where it makes more sense. the air feeds are also better, with provisions for some duct work, if you want to feed the cooled air out of a utility room, while reducing some of the fan and compressor noise. There is not a huge amount of noise, but if it is the only thing on, it will be noticeable.
There are also utility rebates and tax credits.
With an all-electric house, I think they make a tremendous amount of sense.
For the upstairs, and for the forced-air part of your HVAC system, you can put in a heat pump. a little more than the cost of an air conditioner, basically the same equipment, with a reversing valve in the outside unit.
this would be an air exchange heat pump, and provides heat at a reduced energy cost as long as it is not too cold. this means fall and spring. in winter, an included resistance heat element would kick in to give you more heat when the weather is too cold for the heat pump to work.
the difficulty is that to make heat inside the house, the heat pump has to make cold outside, and past a certain point the coil would tend to ice up and not work.
Have you looked at T studs?
https://www.tstud.com/
for your ND electric heat house, it seems like it is worth a look.
https://www.youtube.com/watch?v=mxDSulcLpAE
https://www.finehomebuilding.com/2019/07/16/breaking-the-thermal-bridge-with-tstuds
your plan to spray foam would go with their naked version, and you could revisit your preferred 24 inch spacing. they have a 2x8 replacement version as well as the 2x6. not sure what the cost difference would be.