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MAIN REPORT
Summary Of Findings
The roof framing system of the home has suffered significant structural damages due to the impact of trees toppled during the storm. The storm-related structural damages are limited to the roof structure.
Most of the roof framing members remain sound and the roof framing system may be salvaged by using manual chain hoists to pull the rafters into proper alignment. The roof framing should be renailed and “kick-ties” should be installed to stabilize the roof against thrust.
While damages to the roof surface outside of the area of impact could not be confirmed, we consider it likely that damages did occur. We recommend replacing all shingle surfaces on the main roof area to permit inspection and renailing of the roof decking.
Site Description
The subject property is a two-story, single family residence with hardboard siding on the exterior walls and an composition shingle roof surface. There is a crawl space under most of this building which was not entered for the purpose of this inspection. In addition there is an attached garage which was evaluated. The home generally faces east and is reported to be approximately 9 years old. The building is located on a standard residential building lot within the city limits of Apex, North Carolina. The lot slopes gently from the left rear towards the right front. Photograph 1.
The basic construction consists of a wood-framed superstructure on a masonry stem-wall and pier foundation system. This is a typical method of construction in this area.
Site Investigation
A physical examination of the subject property was conducted by John C. McClancy, PE, principal investigator, on November 8, 1996, beginning at approximately 9:30 am.
Other parties present during the site examination are:
Ms. Susan Simpson, the owner.
Mr. Bill Thompson, a repair contractor assisting Ms. Simpson.
Our site investigation began with an entry interview of the persons present for knowledge pertinent to the investigation. No significant information was conveyed.
Following completion of the initial interview, we conducted a site investigation. Our field notes of the inspection and site photographs are included as Appendices A and B, respectively. The following observations were made which are considered pertinent to the development of our opinions.
E-1 This inspection was conducted on Friday, November 8, 1996 at 9:30 a.m. under overcast skies and with temperatures in the upper 60s.
E-2 Upon our arrival, we noted that the fallen trees, stumps and other debris had already been removed from the site.
E-3 There is a hairline to 3/8" separation between the soffit vent strips and the soffit on the front right roof eave. This is directly opposite the impact area of the tree onto the ridge. There is also some slight separation evident between the soffit dentil molding and the exterior wall siding. Photograph 2.
E-4 There is distortion evident in the roof shingles on the front elevation. This distortion is a slight gap between adjacent shingles, extending straight down the roof line with the impact area at the ridge. The gap resembles a "zipper". Photograph 3.
E-5 There is moderate damage to the rear gutter and some patches evident on the roof surface along the line of the impact of the tree. Based on the distance to the stump cavity fill area and the pitch of the roof, it appears that the tree impacted primarily on the ridge. Photograph 4.
E-6 There is an approximately 16" x 48" hole in the left side gable end wall at the level of the second floor joists where the tree on the left side reportedly struck the house. The hole is covered with plastic. There is moderate damage to the adjacent home on the left side which is reportedly due to this tree. Photograph 5.
I-1 The basic construction of this house consists of wood-framed floor, wall and roof systems founded upon a masonry stem-wall and internal pier foundation. This is a common method of construction in this area.
I-2 In the attic, we observed that the ridge beam is broken at the apparent location of the impact. There are several holes in the roof decking which reflect the exterior patches on the rear elevation. Photographs 6 and 7.
I-3 We observed that there is a single 2" x 8" band on the front elevation along the attic floor joists. The baseplate for the rafters is fastened to the top of the band. This band has rotated outward 1/4 to ½ inch. The band is secured to the ceiling joist by nailing. The rafter plates are secured to the ceiling joists by single nails, which have split out the ends of the joists. Photograph 8.
I-4 There is some minor buckling of the roof decking at a seam between plywood panels. There are no plywood clips between the panels and there is no space between the plywood panels. Photograph 9.
Discussion and Repair Recommendations
It appears that the impact of the tree onto the ridge caused the nails which secure the front rafter plate to the ceiling joists to split out at the ends of the joists. This is permitting the band and rafter plate to rotate outward under the thrust load of the roof. At the present, only the butt-nailed connection between the joist band and the ceiling joists is resisting this thrust load. These nails are loaded in withdrawal and cannot be relied upon to resist the imposed loads. The rotation will probably continue to worsen until repairs are made.
The broken ridge rafter is the result of the impact of the tree. The broken and penetrated areas of plywood decking on the rear elevation are the result of the impact of the tree.
Based on the available visual evidence, we could not determine if the buckled plywood on the front elevation is the result of storm-related damage. This is a common deficiency observed in homes where plywood clips and/or proper spacing between plywood panels is not maintained. However, it is possible that the shock of the impact caused the nails to pull loose from the rafters.
Repair of the rotated ceiling joist band on the front eave of the home will require removal of the front soffit and boxing to gain access to the sill band. Because of the spreading of the roof, repair of this area will probably involve using a chain hoist (commonly called a "come-along") in the roof area to pull the outside ends of the front rafters back in to their original position. Then, 2" x 4" diagonal ties, known locally as "kick-ties", should be installed between the rafters and the ceiling joists to provide a secure connection.
Repair of the broken ridge beam may be accomplished by simply scabbing a new piece of wood to one side. This ridge beam is not a load-bearing member. It simply provides alignment. However, the new piece should extend at least to the adjacent rafters beyond each side of the break. Alternately, the damaged portion of the board can be cut out and replaced.
We further recommend replacement of the roof shingles on the entire right end of the home, both front and rear elevation. While these shingles are being replaced, the buckled roof decking may be refastened to the rafters below. Re-shingling should be performed after all structural repairs have been completed.
Options
Based upon the available visual evidence, we conclude that the storm-related damages are limited to the roof framing. The gaping and separation at the soffit vent and molding on the front eave is the result of the impact of the tree along the ridge of the home. The homeowner did not indicate any structural damage as a result of the impact of the tree on the left side of the home. The homeowner did not indicate any structural damages as a result of the impact of the two trees on the front entry stoop railings. Based upon the available visual evidence, it cannot be conclusively determined whether the appearance of a gap along the roof shingles in line with the impact of the ridge is a result of storm-related events. Based upon the other damages observed, it is probable that this damage is related.
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