Raised heel trusses and window height in elevation
NormanWB
| Posted in Green Building Techniques on
I am asking my builder to include raised heel trusses in my new house, though I doubt my plans reflect that in the elevations. So, what are the implications of this?
– Should window heights be adjusted?
– Overhang distances?
– How will this affect the look of the house?
Thanks,
Norman
CZ3A, Greenville, SC
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Replies
Normal,
First of all, it's always a good idea for your plans and elevations to reflect your actual intent. Trying to use stock plans, and then modifying those plans with marginal notes and oral instructions to the builder, is a recipe for problems.
Second, the way you determine how a change will affect the look of the house is to draw it. If you can't create a new elevation showing your planned change -- in this case, the switch from conventional trusses to raised-heel trusses -- due to inexperience or lack of drafting skills, it's time to hire a designer to help you.
Third, if you are designing your roof overhangs to shade your south-facing windows on the summer solstice, then the distance between the top of your windows and the underside of your overhang (the soffit) absolutely matters. The greater this distance, the wider the overhang has to be.
I have laid this out on paper and it looks like the raised heel will not impact me. Snce my pitch is 12/12, I should have plenty of room at the exterior wall.
Raised heel trusses gives you the opportunity to put the structural header above the top plates.
This allows for taller windows that put a lot more natural light on the ceiling.
Typically for good aesthetics, you try to align the tops of windows with the tops of doors. So if you move your windows higher, you might want to put a transom window or other detail over the door to align the heights.
If aesthetically there appears to be too much space between the tops of windows and the roofline, adding a frieze board along the roofline or other window and door trim details might improve the appearance.
Robert: The good news is that there is only one door on the front elevation and it has a curved transom in a gabled opening, so aesthetically having the windows at a slightly different height should not cause any woes on the exterior.
Richard: Could you clarify how the structural headed would be above the top plate? I thought the trusses would rest on the top plate and that the load from the trusses would need to be transferred from that point down.
Headers can be easily installed in place of rim joists, freeing up window heights. Where you have trusses sitting on the plates, you probably do not have rim joists, so that will not work.
Bob,
With raised-heel trusses you can specify a shorter span where they are over windows and add a flush header and hangers. Just as with headers replacing the rim joist , the results are less thermal bridging and if desired, higher window head heights.