Replies

1. 
   Mike_Smith | Dec 05, 2000 11:02pm | #1

   *
   david... it sounds like a variation of ""balloon framing""

   you need fire-blocking at each floor..

   and the 2x8 studs are not neccessarily a good insulation deal....each stud is only r-7... no mattter what the insulationin the bay is..

   another system would be 2x6 or 2x4 studs with 1 inch or 2 inch EPS foam ...

   lots of ways to skin a cat....

1. 
   Joe_Hennessey | Dec 06, 2000 12:04am | #2

   *David, what length 2x8 did you cost to frame your walls? If you frame from the sills you will need 10' or 18' at least. Is $300 really enough? How big a house is it? Seems like there is a BIG price difference between 8' 2x4s & 9' or 10' 2x8s? Joe H

1. 
   Matt_G. | Dec 06, 2000 12:22am | #3

   *David:You say:"Building the wall from the sill would mean not worrying about most of the studs missing a joist or how to provide a wide enough band board to fully support the 8". "It is not necessary for the studs to be "stacked" on the joists. Although stacked framing is optimum it is not required by code. For example, 24" o.c. trusses are installed on top of 16" o.c. walls in almost every trussed roof house. Further, to do what you propose, you would need a 10" - 12" foundation top to support the floor system. Stick with standard platform framing or go to something totally different like ICF.And you also say:"I did a few calculations; the extra cost in sizing up from 2x4 studs and using 5/8" sheetrock instead of 1/2" (for a little more stiffness) would cost less than $300 for the whole house."Don't forget to add the cost of jamb extensions that would need to be built for your windows and doors. My thought is that if you want to build a high efficiency house, consider upgrading the insulation, sheathing (as Mike says), HVAC system, buy good windows and look at framing techniques such as 24' o.c. 2x6 or staggered 2x4 walls and insulated headers.

1. 
   Boss_Hog | Dec 06, 2000 12:39am | #4

   *Matt G. makes a good point. The cost of jamb extensions could be significant. Another thing to consider is labor. Building with 2X8 would be more difficult than 2X4. You'd probably get a better R value out of the wall by using 2X8 plates and staggering 2X4 studs on the plates. But again, you're adding more labor. One last thought - How wide a foundation would you have to have to frame a 2X8 wall on top of, and still have room to bear your I-joists on ?

1. 
   tedd | Dec 06, 2000 07:39am | #5

   *I wouldn't forget the affects of 8 to 12% shrinkage and expansion. Airtight construction can be pulled apart if the wrong framing members are nailed together.

2. 
   David_Crick | Dec 07, 2000 07:08pm | #6

   *Thank you Mike, Joe, Matt, Ron and tedd for your reply. Sounds like 2x8 walls are not favored too much.Mike - I know it sound ignorant, but what's EPS foam. Is it a rigid polystyrene type board? I know polystyrene has fantastic R values, but I do remember reading that some people don't like nailing siding against it as it doesn't feel solid enough. I'll be sheathing the walls with 1/2" OBX or similar. But it still seems to me that the nails will have limited penetration into anything solid with siding hanging off them at the other end. Is it really not a problem?Joe - I think I worked on 8' for everything. The next increment is 10' and you're right, they're a lot more expensive.Matt - OK. Std platform framing it will be. I've seen 2nd floors at 24"oc over 16"oc walls. At the 1st floor though, how many floors up can you go if say those studs came down midway between 1st floor joists with only the 1 1/2" sole plate spanning between them. Or is the rim board assumed to carry it's share of the wall loads?Ron - the staggered 2x4 walls sounds interesting. If everyone agrees that rigid insulation on the outside is really not a problem for the siding installers or for me in making sure it stays up then I'll go that way. Matt again - I do want high efficiency. Paying more now during new construction is cheap compared with down the road and energy costs will only go up.This leads to my next question. As I want to do as much as is reasonably possible for a handyman I was going to do the insulation myself. I thought that limited me to fibreglass in the walls. Recent postings say that fibreglass is not as good at stopping air movement as blown in cellulose. Some say blown in stuff settles once the drywall's up. I've read that if it's packed enough, it won't settle. The question is then, is blowing in cellulose dense enough a DIY proposition and would the sheetrock have to be in place first.The next question is about not venting crawlspaces. It seems that not allowing humid air in is a good idea. How should the area be insulated?When you could all be working, bidding for the next job or spending time with your families, taking the time to post is really appreciated. Thanks.

3. 
   Michael_Prisbylla | Dec 07, 2000 09:35pm | #7

   *Did the blow-in cells thing a while back in my house. I posted some info in the energy folder for first timers like me. Long answer; go here: Michael Prisbylla "heavens, a cells q that HASN'T been asked" 11/10/00 10:44amshort answer: it's easy.Mike Prisbylla, the idiot DIY guy

4. 
   Mike_Smith | Dec 07, 2000 09:57pm | #8

   *david... eps is expanded polystyrene...with an r-value of 3.6 (density of 1.0 lb./cf) to 4.2 ( density of 2.0 lb./cf)......

5. 
   J.R. | Dec 08, 2000 01:31am | #9

   *David,Have you explored the possibility of using pre-engineered wall panels such as stress skin? These achieve an excellent r-value, with little or no conduction that you would have with a wall stud. Also, I'd be concerned with shrinkage and bowing of the 2" x 8" studs.A book I found very helpful in designing energy efficient residences is put out by our Canadian friends (Canadian Home Builders Association), and is titled "Canadian Home Builders Association Builders' Manual." There are several good techniques that you can incorporate into your design.

6. 
   Gary_Bopp | Dec 10, 2000 08:50pm | #10

   *b LVL QuestionI'm building a basement garage with a floor over and installing 3 LVL's for the garage door header. Because of the weight and lack of manpower, I plan to raise one LVL at a time then glue and bolt them after all 3 are in place. Any better ideas?

7. 
   Mike_Smith | Dec 11, 2000 01:20am | #11

   *nope .. sounds right.. make sure you got good shoring and staging and good clamps...and a powerful framing gun will save your elbow....

8. 
   Gene_Leger_ | Dec 13, 2000 10:09pm | #12

   *David. A better--less expensive--way to frame with stasggered studs is to use full width rough sawn 1x6 plates and 2x3s staggered 24-inches on center. GeneL.

9. 
   paul_frame_boss | Jan 11, 2001 05:57am | #13

   *be care full a lvl isnt always desinged to carry load with hole for bolts i would get th specs if you have doubt. You also need to be sure the bols have the shear ration for the load. Danger will robertson !!!!!!

10. 
    Joe_Hennessey | Jan 11, 2001 09:34am | #14

    *Paul, my oldest loved that program. "Danger Will Robinson" Haven't heard that in a long time. Joe H

2. 
   David_Crick | Jan 11, 2001 09:34am | #15

   *
   A little while ago, I read a posting that refered to an idea to frame the external walls up from the mud sill rather than from the top of the first floor structure. Can anyone remember what the reason was for this approach? Right now I'm getting my ideas together to draw a set of plans & I'm thinking of (purely for insulation reasons) 2x8 studs @ 24" with I-beam floor joists at 19.2". Building the wall from the sill would mean not worrying about most of the studs missing a joist or how to provide a wide enough band board to fully support the 8". I did a few calculations; the extra cost in sizing up from 2x4 studs and using 5/8" sheetrock instead of 1/2" (for a little more stiffness) would cost less than $300 for the whole house. (I haven't costed the extra insulation). It seems that I could get the $300 back in not too many years in energy savings. Comments on this would truly be appreciated. (PS. I'm not a builder. Years ago, back in the UK, I was a civil/structural engineer, so I want to be an interested party in the contracting of my first and probably only house here. I'd truly appreciate your comments.