Hello. My name is Michael and I am brand new to this website. I will be building a house in the mountains of northern NH and wanted to find out if anyone here has information or experience with double wall construction. We have beautiful views so I will have alot of glass. I want to make sure in the cold winters with this large glass views that we keep the house as energy efficient as possible. I will address the windows later and I wanted to discuss the types of framing options for energy effcient homes.
Where are there good sources of info regarding this type of construction? I have searched this website but only found one message. I would be interested to see how this compares from a cost and energy efficiency perspective with Timber frame homes with the stress skin insulated panels.
Any help folks could provide me with would be appreciated. I apologize for being sketchy but I figured I would be more specific in later posts.
Thanks,
Michael
Replies
First check out enerystar.gov I think. I have not been there but need to check it out and here it is real good.
Second it may depend what code you are using and if there are codes in your area. MY point is we have just adopted the IRC or International Residential Code as part of this we are using the IECC or International Energy Code.
The IECC breakes the requirement into two packages the Prescriptive Package Approach and the Performance Package. The later involves the MECcheck metod witch uses software download from http://www.engerycodes.gov.
The Prescriptive Package Aproach uses charts and breaks the country into zones. You are wrong not to include windows now in these approaches. You start with and find your glazing area as to a % of ext wall area, then glazing U facture then heating and cooling package the chart for your zone will tell you the ceiling, wall, floor ect R-value you will need.
example my zone 13
package 1 glazing 8% glazing U 0.45 normal heat will require ceiling R-38 wall R_13 Floor R-19
Package 28 glazing 22% U-factor 0.40 High eff Heat Cooling will Require ceiling R-38 wall R-13 Floor R-19
Both package have the same insulation but with better heat and windows you get more glazing.
You must take the whole package approach in other words to get what you want.
Hi Wally,
Thanx for the reply. I agree with everything you say and I am investigating the websites you referred me to. Hopefully they will help. My issue is still regarding the double wall vs. other types of house construction.
Your suggestion is about 3 steps ahead of me (I am a novice here) as I need to design what I want with regards to heating systems, types of windows/glass and how much I can afford energy wise and also the construction of the house.
I am still in the brainstorming phase and don't know anything about double wall vs timber frame vs. 2x6 stick vs anything else. A contractor I used to work with years ago always said "we can do anything you want if you have enough money". I didn't by Microsoft at the initial offering so I have to make do with what I have.
I am not afraid of doing things myself with the right tools and equipment. The best tool I can get right now is information and your suggestion is appreciated and will be used.
Do you have any sites for double wall construction? The process interests me as it seems simple enough if you have the space. Any help here gets me closer to where you (and I) want me to be.
Thanks again Wally.
Michael
Nothing on double wall it is usually used only on adjoining apartments or duplexes, more for sound. You can get close to the same result with 2x6 24 on center ridig foam board and R- 22 insulation instead of R-19 and uses a lot less wood. Or what about foam pannel construction, It takes a lot of the do it your self out of it but It goes up fast.
Remember you can over insulate. That is why mold is a big Issue now.
Side note an early issue of FHB had a house in Canada He used open web trusses to frame with and I think r-38 walls. I often wonder of how his health is that house was airthight like a chest freezer.
The key with a highly insulated house is to have air exchange. I believe that in Canada, the building code requires some sort of air exchanger; generally, they are hrv, heat recovery units, so you don't waste heat. ANd every room should have a duct to the exchanger system.
"Double wall construction" (at least in my area) is an old term meaning that there is sheathing on the studs under the siding. Try doing some searches under "super insulated construction". I think you will find that there is quite a bit of research out there. There are alternative methods, to the double walls, that may be more more cost effective and are worth investigating. Also, your state university may have done research that you can access.
Try doing a Breaktime search for the exact pharse "Leger House"
That should give you a few hits that may (or may not) be interesting.
Another day, another tool.
Try a search for Larsen trusses. That construction has a 2x4 inside wall for running utilities, then it is sheathed, and a 12" thick web frame is constructed on the outside and insulation placed here.. Is that the one you're after. Some years ago there was an article in FHB about a house in vermont that was built that way.
The way we're doing our new place is 2x6 inside walls with spray foam, then sheathing, and then 1 1/2" rigid insulation on the outside (I'm leaving out a few layers) That provides a thermal break - as you lose a lot of heat along the 2x6's. They're a thermal bridge. Gives us R32
The other thing we considered were SIPS, structural insulated panels, but my contractor was not familiar with them, and felt better doing stick construction. If he had been more comfortable, or we had more time to research them, I really would have considered SIPS. However, I just found out about them a couple of weeks ago, and we're planning to dig next week.
If you're planning on lots of windows, take into consideration your exposure, there are definite guidelines for %age window to floor area, and direction of sunshine. Overhangs have to be planned for your latitude. Don't forget about overheating in the summer! West windows can be a real source of heat in the summer, and not too much heat in the winter, due to height in the sky.
Caution: I know nothing about building houses. I just like to lurk here.
I've done double wall superinsulated for a number of years and finally switched to 2x6 2' on center and 1" foam on the interior side. We don't get the thick wall look of the former but it's less expensive and I'm not sure anyone can tell the diff thermally
When we're really serious we strip the foam with 2x2 horizontally inside and use the chase space for wiring.
Some guy commented on overinsulation and mold. That is such #### - there are perfectly ordinary houses out there with mold, which comes from water leaking into your house and not being able to get out, usually from shoddy construction practices like subbing out everything like developers do, and has nothing to do with superinsulation, though it can happen there if the vapor barrier is on the wrong side of things and a shoddy developer (redundant?) does the work.
Read more and be careful what you hear online....
Godspeed in the face of the Bushies
Don
My thanks to all that have replied so far. All good ideas. I will still be doing research for about a year. My wife and I will be breaking ground about 1 year from now at the earliest. It is sort of a 5 year plan that has lots of time to be done so we want to do it right. We will be taking measurements of sun postition and pictures during each season to see where the sun is in relation to the land, what the spring runoff from snowmelt looks like and how the mountains look each season. This will help us in terms of planning house position in relation to the sun, max cooling in the summer and max heat in the winter (hopefully not the opposite!!).
I appreciate all the replies and will be here asking questions about siding, flooring, windows, metal roofs and construction techniques. You folks are a great help and I am sure I will be learing more as we go forward in this process.
Thanks again,
Michael
Michael,
I'm sure I speak for all of us when I say that we look forward to your future queries and posts and following your progress. If you manage to come up with the means to post pics of the project as it moves along, we'll really be happy!
Best of luck!
Rich Beckman
Another day, another tool.
Also, check out the R2000 standards developed in Canada for energy efficiency.
My post above was ment as a reply to McMick not to the orginating post. After all this is about the exchange of knowledge.
True there are homes built that are standard construction and have mold problems. I have a tenant that has just rented from us and she gave her house back to the bank, because of a ground source water problem causing mold. This is effecting 80+ houses in her subdivision. The builder is in the top 100 in the US according to Builder Magizine.
But the avarage Family of four through body heat, cooking, showering, breathing, house plants,etc. puts out something like 30 gal of water vapor in a homes air in a day. In a super insulated house that vapor needs a place to go or mold can start to grow. In the March issue or Professionalbuilder there is a articial that covers energy efficient construction it in no means goes into any depth. But one suggestion they have is to install a fan in the upstairs bath that is low sones enery efficient and set to be on all the time to provide circulation. I am not saying that this is as good as a air to air heat exchange ventilator but it is better then nothing.
By over insulating I ment there is a point where the extra materials labor ect are going to stop providing you with any return on your spending. Last mold is not the only problem, breathing stale air with no oxgen is also a problem. I was just trying to get the message across that houses need to be designed as a whole package ie. heating,air conditioning, insulation, appliences, windows,sky lights,door etc. These things need to work together not against one another. That is what the energystar program is about. if you got to open the windows in winter to let in fresh air because 'honey the air is to stale in here' what is the sense of insulating.
Last I agree don,t believe everything just because it is posted here.
Wally
"Why can't we all just try(sniff) to get along (sob)" Rodney King
Super insulated homes have a variety of problems of their own. This site is generally concerned with infiltration of urban pollution but you may be able to glean some useful information. http://www.hhinst.com/archives.html
Turtleneck
The only difference between a rut and a grave is depth