SomeConstructionGuy t1_j6nr9ld wrote on January 31, 2023 at 5:12 PM

Reply to comment by 8valvegrowl in Really want to build a house like this. Passive home stays at 70 degrees in Maine w/o furnace. by Twigglesnix

The timber frame/sip combo is a great setup.

With recent spikes in foam prices were getting r40 walls and r60-80 ceilings for similar or lower cost than sips. In our experience with sips it’s been very easy to get a decently tight house but hard to get a very tight house. Getting to 1 ach50 seems easy but getting below .33-.5ach 50 hasn’t been consistently easy. The double stud alsogive a lot of benefits such as being able to run plumbing in exterior walls.

Overall we’re so much better at this than 10 years ago. Being unsatisfied with 1 ach50 was nuts in the US 15 years ago.

8valvegrowl t1_j6nzfc1 wrote on January 31, 2023 at 6:02 PM

For sure...I seem to recall my house fell in the 0.5-0.75 ACH50 range, which is pretty tight. Interesting to know that foam prices have risen so much. We paid as much for the SIPS as we did for the timber frame (About $30K for frame and $30K for SIPS in 2019 prices)

Is the double stud scheme staggered? It's pretty fascinating how much the state of the art changes in building tech...seems like so much is pretty much built using legacy techniques still.

SomeConstructionGuy t1_j6o1e1o wrote on January 31, 2023 at 6:14 PM

That’s still a very tight house, nice work!

It depends on the builder/architect/engineer. I like to treat the interior wall as non load bearing and stagger it from the exterior. More thermal break makes me feel good and then we can make the stud layout an even 16” from one corner on the inside so drywall and trim are easy. Realistically if the wall is 10” thick you still get an r12 break wirh aligned framing and the total r value is only knocked down by 5% or less.

8valvegrowl t1_j6o2406 wrote on January 31, 2023 at 6:18 PM

Yeah, makes sense. Good stuff. I know in the future if we have an addition made for a first floor bedroom, we may consider stick built on a slab, so great to hear about options for construction! Thanks for all the info.