new ‘Energy Heel’ Roofs

Return to Community Posts
Viewing 7 posts - 1 through 7 (of 7 total)
  • Author
    Replies
  • #13559
    SDSSDS
    Participant

    With the new 2018 building codes going into effect, the powers that be are pushing harder for that new energy heel truss . They’ve even included a 1/2 credit option in the new energy codes. If you’re not familiar, it’s basically a cantilevered eave rather than a sloping ‘tail’ eave.

    This method created a flat soffit instead of sloped, allowing increased height directly above the exterior wall, providing a space for insulation so that it isn’t compressed at the exterior walls…resulting in a more energy efficient home.

    I’ve modeled a roof in this manner recently…well not the first time but…with intent, and the only way I could make it happen accurately was to offset lines from the exterior wall face for eave length, then use them to draw in the roof, with only enough overhang to force a visible fascia board.

    The problem is in the soffits…in order to show an ‘enclosed soffit’, which is a must on a flat eave, you have to then draw in ceilings at all overhangs to ‘enclose’ them on the underside. Very cumbersome indeed.

    Is there a way to make the roof project a flat soffit to the ‘interior’ side of a roof?

    What are Cadsoft’s plans to address these new innovations in roof design?

    #13562
    FynrDzynrFynrDzynr
    Participant

    G’day SDS!

    Could you Plz provide links to details in your codes. As an Aussie I’m very interested in how other jurisdictions tackle energy challenges.

    avagr8day

    Merv

    #13564
    Alreedbuildersalreedbuilders
    Participant

    Just go into your roof setting and set your roof support height (on all eves) to match the heal height you desire, then in all your exterior walls set the siding so it extends past the top of the wall to meet the soffit or like I do I just extend the top of the siding the same distance as my heal height minus 2″s. The extra siding figured in if not used the owners end up gratefully because the have some extras in case they need to replace some now and again. You can still use trusses in the program and you can still slope your soffit like they did in the old days if you want to. You don’t end up having to insert ceilings as your soffit doing it this way because the soffit still takes its depth from the walls. Also don’t add another building location for your roof due to the raised heal, just go into the roof settings under support and raise your heal height there. the only thing extra you will need to do is figure in the additional OSB wall sheeting to cover the raised heels up to the bottom of the truss top cord.

    I have always included raised heel trusses in my designs and buildings. The reason I have always done this is because when there is only 4″ above the exterior wall it does not leave enough room to insulate correctly and what happens is the drywall on the ceilings for 6″ away from the exterior eve walls becomes cold which wicks through to the inside of the drywall and when the warm moist interior air hits the cold drywall you end up with moisture buildup which ruins the paint and the paper face of the drywall. I have seen this way too many times especially after the insulation settles and compacts. Don’t believe any insulators who tell you that their insulation doesn’t settle because its just not the case. Gravity always wins over time.

    #13571
    SDSSDS
    Participant

    G’day SDS!

    Could you Plz provide links to details in your codes. As an Aussie I’m very interested in how other jurisdictions tackle energy challenges.

    avagr8day

    Merv

    See link below Merv, scroll down nearly to the bottom of the page to section N1102.2 (R402.2) Specific Insulation Requirements (Prescriptive)

    https://codes.iccsafe.org/content/IRC2018/chapter-11-re-energy-efficiency

    This is in the US. We update building codes every 3 years here and are just now switching to the new 2018 codes which include some extensive energy code changes. There’s also a separate energy code but I won’t link to it as each state adopts their own version so things vary state to state.

    I design mostly in Washington & Oregon

    #13572
    SDSSDS
    Participant

    Just go into your roof setting and set your roof support height (on all eves) to match the heal height you desire, then in all your exterior walls set the siding so it extends past the top of the wall to meet the soffit or like I do I just extend the top of the siding the same distance as my heal height minus 2″s. The extra siding figured in if not used the owners end up gratefully because the have some extras in case they need to replace some now and again. You can still use trusses in the program and you can still slope your soffit like they did in the old days if you want to. You don’t end up having to insert ceilings as your soffit doing it this way because the soffit still takes its depth from the walls. Also don’t add another building location for your roof due to the raised heal, just go into the roof settings under support and raise your heal height there. the only thing extra you will need to do is figure in the additional OSB wall sheeting to cover the raised heels up to the bottom of the truss top cord.

    I have always included raised heel trusses in my designs and buildings. The reason I have always done this is because when there is only 4″ above the exterior wall it does not leave enough room to insulate correctly and what happens is the drywall on the ceilings for 6″ away from the exterior eve walls becomes cold which wicks through to the inside of the drywall and when the warm moist interior air hits the cold drywall you end up with moisture buildup which ruins the paint and the paper face of the drywall. I have seen this way too many times especially after the insulation settles and compacts. Don’t believe any insulators who tell you that their insulation doesn’t settle because its just not the case. Gravity always wins over time.

    Yes, the alternative is to simply raise the roof plane heel height directly above the wall, but that is not what I was referring to. I was referring to a cantilevered roof system, not a raised heel roof system.

    As well as a building designer I was a home builder as well as a mfg’d truss designer and manufacture for many years (using Mitek software & plates) and there is a marked distinction between the two systems from a truss manufacturing standpoint. Certainly from a builder’s perspective as well.

    While the raised heel method still provides a sloped eaves, almost a requirements for the popular Craftsman style around here…the cantilevered approach is actually a more common, practical and cost effective application in most cases.

    I use both…but Cadsoft only easily and readily supports the raised heel method as you’ve pointed out. I’ve uses both for years and not just for energy reasons…raised heel trusses are a very handy design tool to get around a lot of structural concerns and avoid the need for an engineer’s stamp.

    I’m just curious if others do, how, and if Cadsoft has any intention of implementing a method for cantilevering a roof.

    #13578
    Alreedbuildersalreedbuilders
    Participant

    Apologies, I now know what you are referring too. I always just drew the soffit in myself, the fun part is getting the elevation correct to match correctly. I wonder if you raised just one eve support height then modify your overhang width. If using standard box return maybe you can enter a negative measurement so the box return isn’t as long as the adjusted overhang width? I’m not at desk right now to try it.

    I have always wanted to see how a set of trusses is designed and engineered. One of the few things I haven’t had a chance to see. It’s always nice knowing what a guy can do with them and also any limitations or work arounds. I still love being on the sights building although the older we get the harder it is to go to the office after work to get estimates and plans done. Lol

    #13596
    SDSSDS
    Participant

    I really miss truss design. It’s a lot of fun actually, the closest thing to framing on a computer I’ve come across. The layout programs use 3d models and were my first introduction to 3d modeling back in the late 90’s. Up until ’08 I designed all my own truss packages for my home designs and it allowed me to be very creative and push the limits of what trusses can do (we built them too).

    Unfortunately you have to be a truss manufacturer to licence the software and I have no desire to get back into the production side of truss design, so I’m patiently waiting for the day they make it available to all.

    There are some big innovations and integrations going on between Mitek and Strucalc, among others. Some day we designers will design and engineer homes from roof to foundation, all in one neat little package!

    Ahh dream a little dream eh?

Viewing 7 posts - 1 through 7 (of 7 total)
  • You must be logged in to reply to this topic.
Return to Community Posts