Calling all Carpenters/Structural Engineers. New home construction ???

Thanks OZ. I do have taller walls then the neighbors but only by a foot. When I told them about this build I told them efficiency is my main priority. I upgraded the heating unit to Lennox 97% efficiency and the A/C Unit to 16 SEER but I didn't realize stud spacing could have anything to do with thermal efficient until now.

 

Yeah I literally have a paper full of questions to ask when I go lol

 

Wood is only R1 per inch , in a typical fibreglass batt filled 2x6 wall you can put in R20 batt insulation , but every where there is a stud , the R value drops to 5 1/2 because the wood allows the transfer of cold ( and heat ) through it . Less wood in the wall assembly raises the R value of your wall assembly . This is the reason high efficiency houses use a layer of exterior insulation like foam or rock wool to insulate the framing and minimize thermal bridging

 

Ever notice a house on a frosty day where you could make out the studs or rafters from the outside because there was no frost there ?

Thats thermal bridging

 

Some places the code will say that spacing is ok..... So here's the difference. In Va it is 16" on center (oc) do you have to do that? No! You can go 10" if you choose to do so. It's going to cost you more obviously. Now up in Pa. I've seen 2x10 on exterior walls and 2x6 on interior..... Why? Two reasons, they have lots of snow in the mountains, so that extra board size and spacing spreads that snow weight way better. It also allows for more insulation in the walls as they have deeper pockets now. So that being said its up to your local building code for the minimum and what you and your builder decide. If it were me I would absolutely want mine at 16" on center in any case no matter what size board is used. Jmo

 

Are you doing the wet (damp) blow cellulose insulation?

That would be awesome in your climate. Great continuous r value and decent air barrier

 

I don't think I'm going to have insulation on outside just the house wrap and the new siding board(its not aluminum or vinyl) I forgot what's it called that's supposed to be strong and its dense when you knock on it. So with everything you know about my house and insulation you say its a good build strength wise and efficiency wise?

 

Yea they are spraying that in the walls R-23. It was a $1900 upgrade to the whole house so I hope its worth it

 

I guess 19.2" is best of both worlds in terms of strength and efficiency. Which efficiency was main priority then build strength close second.

 

You mean fibre cement siding like Hardi Plank ?

I was just putting the exterior insulation thing out there to demonstrate my point about thermal bridging

I'm sure your builder understands what your local code is with respect to stud spacing and I would not be concerned about it judging by the pictures you posted

Does it not state a stud spacing on your approved permit house plans ?

 

You're definitely gonna lose efficiency with the 9' walls (larger envelope area with same usable space as 8' walls and yer heat's gonna go.....up) but other than that seems like you're on the right path. Should be a really nice house.

 

Yea it's Hardi Plank. Is that good siding? Here are a couple pics of building notes

 

Sorry for pics coming out sideways

 

I figured with taller walls comes higher heating bill, also have vaulted ceiling in master bedroom. I hope it turns out great its my first brand new home.

 

Hardiplank is great for dry climates like yours but I've torn too much of it off here in wv to consider using it in wetter environments

 

How are they insulating the vaulted ceiling to get r50?

 

I have not a clue but they better do it I paid extra for it. I have contemporary roofing so my roof line is not high at all. Its a slim roof line

 

Here's a pic of the house and roofing line...as you can see it's not a tall roof so R-50 will be a challenge but they offered it as a option and took it.

 

Vaulted trusses generally have enough depth for R50 except maybe at the heel , it depends on the inside pitch versus the roof pitch

You could do something like stacked high density R28 batts

 

that would definitely be more economical than the spray foam option.......also friendlier to the shingles lol