rafter framing angles and grouted sill anchor bolts), along with possibly an inadequate lateral connection of the old roof structure to the walls, in order to use the old roof framing as the lateral tie. I would suspect there isn't a heavy connection where the rafters connect to the old wall (e.g. Either option will keep the ridge line from sagging and also keep the walls from bowing outward. for a roof structure like that there needs to be either a tie across the building (low rafter ties, ceiling joists, or strap ties) or the ridge can act as a beam with adequate strength and supports. Also, for new construction IRC R802.3.1 would require an engineered (alternate) design for anything other that rafter ties at the wall top plate or ridge girders. with larger rafters and heavier bolted connections. Note that ya can go higher than 1/3 above the walls with the rafter ties, but it has to be an engineered design to work. … Great post and explanation of the difference between rafter ties and collar ties … … I saw that Fine Homebuilding article you linked, and it has an excellent discussion of common framing problems. I would notate the lack of collars or kneewalls in your report, but if you are not seeing any noticable deflection or sagging after 10 years, it probably is unwise to call it a defect. Also gable roofs are a lot more fragile in this regard than hip roofs. That said, I see these problems mostly were the roof pitch is greater than that in the photo. Could certanily lead to catastrophic failure if let go. Luckily, if the roof dosen’t collapse when the are removed, the problems arise gradually and can be corrected if caught quickly enough. Leeds to a lot of other problems too, like gutters seperating from the fascias, seperation of ceiling and floor joists, window and door frames losing square. Most often it will take a while for the effects to show (outward bowing of the side walls, flattening of the roof almost like a pagoda, etc.). I’ve come across this quite a few times where the collar ties have been stupidly removed. Serving Northern KY & Greater Cincinnati Posted By: rfarruggia Needles to say I did not go into great depths in the report, I differed this one to a structural engineer/contractor.Īny input would d be appreciated, I am looking to understand if this is a concern or if I am being overly cautions. My concern is the lack of collars and in a heavy snow for example that the rafters pushing downward would also push the walls outward causing failure of the block wall/roof. Also space approximately every 10' or so is a vertical support with a short piece of lumber under them resting on the original roof as a support. The top plate appears to be secured to the top of the walls. What concerned me was that the rafters do not have any collar ties and that the rafters sit on the top plate with a birds mouth notched in them. The wall structure of the home is block with stucco finish and the perimeter walls are approximately 12" above the membrane roof. The rafters were stick built spanning approximately 28’ from front to back of the house on a pitch of approximately 4/12. When I viewed the roof from with in the attic (hip roof) I discovered that the original roof had been a flat roof with rubber membrane. I understood many of the issues/remodels but had a concern when I saw the “new” roof from within the attic. I inspected a home built in the 40’s that has had major renovations done in the past 10 years. This post was automatically imported from our archived forum.
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