Wind Mitigation - Hip or Other??

Hi all,

Looking for some guidance here. This roof is all hip but has this elevated shed style roof on the rear side of property. Total perimeter is 240 and length of shed is 16 feet. I know that is less than 10% but do I have to count all 4 sides of the shed style roof section?

Thanks,
Kevin

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You have to count the top AND the two ends of that celestory roof as non-hip. The lower eave on this is hip. But, also include all four sides of this in the total roof perimeter. Looks like the non-hip will be over 10%.

You are going to get all kinds of answers on this. The correct way to do it is to measure the entire elevated roof and add that into the perimeter (if you have not already). The two down slopes count ans no hip sections (which by your calculations should be 32 feet).

Others will tell you that the elevated roof does not count as total perimeter - they say take the roof from the satellite view and just go around the outside. That would leave this roof as on hip. That would be incorrect, as the elevated roof is a separate roof system. Hope that makes some sense.

Great example Kevin, this helps expose some of the issues created by using current antiquated methods of determining roof geometry.

First, the form asks you to measure the “total roof system perimeter” AND “non-hip features”. But, the form never tells you what exactly is a “non-hip” feature.

The short story is, a non-hip feature is any portion of a roof structure that is not reinforced or constructed properly, it can also mean a damaged or failing roof structure. That’s the short definition. To assume anything else implies that the roof structure could not benefit in any way from reinforcing but only “reshaping”….and that simply isn’t true for any roof structure.

A few questions: Where is the home built (county/municipality)? What year was it built? Are the perimeter walls framed of the roof structure (trusses) or are they balloon framing? Has the home been retrofitted at the roof to wall connections? What are the current roof to wall connections? Are they framed walls above the main roof structure that have load path connections in place? Has the roof covering been replaced with an PA/NOA roof covering? How was the roof deck secured?

The reason I ask these questions is directly related to the way an insurer will assess these features combined. In other words, a hip roof geometry may not receive a “full credit” by an insurer if the other features have not been updated. I have done some consulting in the past and this is how the modeling software works. A home will receive a “percentage” of a hip roof geometry if the other features have not been updated (roof covering, roof deck, roof to wall connections).

In order to answer your question, I’ll need more information about the structure.

Thanks Bradley, that what I was thinking. In addition to that, the roof attachments in main home are single straps but it is unknown what holds this section of the roof. Would single strap be appropriate or unknown?

**708.8.1.2 Partially inaccessible straps. **
Where part of a strap is inaccessible, if the portion of the strap that is observed is fastened in compliance with these requirements, the inaccessible portion of the strap shall be presumed to comply with these requirements. *

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Thanks Robert.

Home is in Orange County Florida and built in 1970. Sheathing is dimensional lumber throughout structure and has a 2017 (now) architectural shingle roof. Challenge is that this “shed style” part of the roof structure is inaccessible from attic space so unable to determine further. Roof to wall connections in main hip section of roof structure are single strap.

Hmmmmm, Single wrap on a 1970’s home… Will you post those pictures?

Thanks Robert.

Home is in Orange County Florida and built in 1970. Sheathing is dimensional lumber throughout structure and has a 2017 (now) architectural shingle roof. Challenge is that this “shed style” part of the roof structure is inaccessible from attic space so unable to determine further. Roof to wall connections in main hip section of roof structure are single strap.
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My first question would be, does it have a continued load path? In other words, are the supporting walls attached to the roof structure via anchors from the walls to the lower trusses? You can see this typically on a garage roof structure that changes direction from the main roof structure. The framed rafters will have metal connectors attaching them to the main roof structure.

If these are not present, it’s a moot point. If they are, this home “could” be built to a higher standard. During the early 80’s, we were not installing these connectors.

Remember, if the roof structure is not used to frame the exterior end wall…it’s not a “gable end wall”…it’s just a “gable wall”. A “gable end wall” is framed of the roof structure, a “gable wall” is simply a exterior wall with the same shape as a gable end wall but is framed with a wall structure that extends down to the foundation (not all exmaples).

Lets put it this way…If I was insuring that home, I would want to know how that upper roof was attached to the support walls. There is a lot of risk there being in the center of the living space. But, it falls into the category of presumed allowed exemptions, such as bump out flat roofs that you can’t verify. The only way to verify the RTW connection for that roof is to open up the soffit and look. Your call…

Michael,

Kind of hard to make out but seems as 2 nails through front and 1 in back as well as tied into bond beam. Thoughts?

why would that be so unusual?

Not sure about the 70’s, but in the 80’s you had to request that the anchor be wrapped over the truss, or specify it on the plans. We always put three nails in one side of the truss and bent the anchor back over the nails.

It was uncommon for us to wrap it over the truss, especially with 10X wood decking as you may accidentally cut through the anchor and ruin the saw blade.

I have not seen many 70s era homes with incorrectly installed straps. On the other hand…the 80s rtw connection is a crapshoot! :slight_smile:

Seen 100’s if not 1000’s