Energy Star - Contractor Talk - Professional Construction and Remodeling Forum

monticellohomes · 07-08-2008, 05:29 PM

I've recently bid on a job that will be an EnergyStar home and have signed up with energystar.gov to be one of the only local builders in my area who has taken this step. But was curious if anyone else has done this or done these projects that might have advice for me. This would be a custom, granted if I get them to sign on the dotted line, so the smoother I can make things work the better for me and my customer.

cleveman · 07-08-2008, 09:13 PM

Put your location on your profile.

I've built 3 energy star homes here. It's no big deal. Just get the spec sheet from your energy company(s) and meet the specs. The first time I built, I failed the test because of the water heater. They just passed me after I sent in a receipt for the correct water heater.

I think they required r-19 walls. I wanted to use 2x4 construction, so I first braced the walls with metal bracing, then sheathed with 1" polystyrene. I had r-13 fiberglass in the walls, so that gave me r-18. Plus they gave me r-1 for the airspace between the brick and the sheathing. Maybe they have me r-1 for something else as well. Anyway, I got the job done with 2x4's and I was happy about this.

I think they wanted 40 in the attic and I blew in 50. I had 2" polystyrene on the exterior of the basement walls and it was all buried a brick or two up. This met their r-10 requirement for the basement. They wanted r-19 for the rim joist. No problem. I also brought the polystyrene on the exterior down over the rim joist by piecing in scraps.

The infiltration test is the most difficult. they set up a blower in your door. I passed that with flying colors and the guy told me I should really have something to introduce fresh air into the house. He said that if I ran the clothers dryer when the hot water heater was running, it would pull co down the flue.

Get all the stuff approved beforehand if it is questionable at all.

The only thing I wish I'd have done was use energy-heel trusses.

Put your location on your profile. I'm sure the rules are more stringent the further north you go.

monticellohomes · 07-09-2008, 12:12 PM

What are energy heel trusses?

I had thought my location was in until you mentioned it.

The homeowner is wanting to do spray foam insulation and actually wanting to do the 2x4 walls then with a 2x2 running perpendicular to we avoid as much as possible the 2x4 being the weak link. I'd like to help them find a cheaper alternative given the headache for all other trades that are used to installing on vertical running studs. But my insulation should be sufficient and I am hoping it will help with my air infiltration as well. I had also already planned for using a air exchanger for just the reason you mentioned.

I just want to figure this out pretty well so I can duplicate it on spec homes I build given I'm one of the only few registered energystar builders in the area.

Construcfla · 07-09-2008, 01:02 PM

Pardon me for jumping in.............just found this site. If you are looking at spraying foam in the field why not go panelized as a stronger and cheaper alternative? Much more efficient. I deal with a company out of Alabama that provides 2" x 4" steel framed wall panels that include closed cell polyurethane.

monticellohomes · 07-09-2008, 06:05 PM

Its worth looking at. I'd have to look at the numbers to see if it is cheaper here than the other.

cleveman · 07-09-2008, 10:02 PM

Energy heel just raises up the "heel" where the top chords meet the top plate of the wall. This allows for more insulation in that small area of the triangle in the attic next to the wall.

I've never done the foam. What R value are you wanting to achieve?

The cat's ass would be 8" ICF walls in the basement and 4" ICF walls above.

I thought at the time that the 2x4's with 1" polystyrene on the exterior was good, and I still believe so. You could upgrade to a foil faced polystyrene and get one more R, but the bricklayers go blind laying against it.

You could do a 2x6 wall and get R-19, then 1" poly for an r-24. I think the 4" ICF walls have 2 1/2" of foam on both sides for an r-25.

My houses get hot in the early evening. I don't know if it's the delayed heat coming in through the brick walls facing south, or the roof.

Another problem I had was that I had to set the AC temp down to about 74 to get it to run. If I had been smarter, I would have just run a dehumidifier all the time and left it at 76 or so. The problem was that it didn't run enough to dehumidify the house.

good luck

monticellohomes · 07-10-2008, 07:17 AM

Yeah we've got a thermostat we started using that has a recirculation setting for situations just like that, so you can suck humidity when the cooling or heating isn't needed.

This homeowner is pretty insistent on spray foam, this would actually be my first house fully with foam. We always do a foam package where they foam around all the windows and any other cracks. But it is hard to get a number on the foam, my insulation guy tells me he's tried to put an R factor to it but there is no air infiltration so it's hard to do...but others claim close to R40-50.

I agree the ICF if probably the ultimate, but around here it just hasn't taken off yet and adds so much more to the cost. I bid one for some friends and the ICF added $9/SF or $35,000 to the cost of the home compared to regular construction. People just are not used to working with the product, they don't have the confidence to build the walls, frame on the walls, etc.

We've done the 2x6 walls with R19, just didn't think to add the 1" foam...and it was on my mom's house, wish I had. But that same idea might be ideal for this foam house, instead of running 2x2's horizontally...just add 1" foam outside and its done.

hatchet · 07-10-2008, 04:19 PM

IMO the SIP panels outperform ICF, with less cost, in most climates. Maybe ICF would be better in someplace like Arizona - or high heating climates.
If you want true r-values check this out (not affiliated) http://www.ornl.gov/sci/roofs+walls/...f/TechHome.htm
The test data has a bunch of information - so on a few of them you really have to look for where they denote R-Value.

orson · 07-22-2008, 10:03 PM

Quote:

Originally Posted by monticellohomes

This homeowner is pretty insistent on spray foam, this would actually be my first house fully with foam. We always do a foam package where they foam around all the windows and any other cracks. But it is hard to get a number on the foam, my insulation guy tells me he's tried to put an R factor to it but there is no air infiltration so it's hard to do...but others claim close to R40-50.

R values do not factor "infiltration". The R value of a polystyrene board or fiberglass bat do not account for air leaks and thermal breaks. Spray foam has specific R values per inch based on the type of the foam. Your insulation guy is full of pooh.