9 ft. High Rear Deck is Found to be Unsafe GENERAL INFORMATION Name of Homeowner: Steven Taylor Weather Conditions: Sunny, 80° Parties Present During Field Inspection: William Stanton of Criterium-Stanton Engineers Sources of Information: Field observations. WoodWords structural engineering software. Purpose of the Investigation Inspect the condition and design of the deck. Determine if the deck is properly constructed. If structural repairs are needed, determine the approximate cost. Orientation Unless otherwise stated, all directions (left, right, rear, etc.) are in relation to an observer facing the front of the house. | Top | Table of Contents | DESCRIPTION OF DECK The deck is in the rear of the house (see photos in Appendix A). It has two levels. The upper level is 20'-8"" long by 11'-8"" wide by 9' high. The lower level is 12'-10"" long by 10'-0"" wide by 4'-6"" high. Stairs lead from the upper to the lower level to the ground. Pressure preservatively-treated lumber is used throughout. The deck is located over a 6' high brick retaining wall. Brick buttresses help support the wall. There are several step cracks in the wall. The cracks vary from hairline width to 1/2"" wide (see photos in Appendix A). The upper deck is supported by 2x8 joists at 2' on center. The joists frame into an interior girder consisting of 2-2x8's and 2x8 perimeter bands. 4x4 and 4x6 wood columns support the deck platform. The height of the columns varies from 8' to 9'. Some have 2x4 knee braces. The deck platform sits on top of the columns. The platform consists of 3/4"" tongue and groove flooring over a 1 1/2"" wood subfloor. The platform is attached to the house with a 2x8 ledger that is thru-bolted onto the brick veneer. The lower deck is supported by 2x10 joists at 2' on center. The joists frame into perimeter 2x10 bands. 4x4 wood columns support the deck platform. The columns are 4'-6"" high with the exception of one column which is 10' high. None of the columns has knee braces and they are attached to the perimeter bands with nails. The platform consists of 1 5/8"" x 5 1/2"" deck boards. | Top | Table of Contents | METHOD OF INVESTIGATION I went out to the site, inspected, and photographed the deck. I made a detailed sketch of the deck and supports so that I could perform an accurate structural analysis of the strength of the members. I returned to my office where I used a structural engineering software package called WoodWorks to analyze the deck. I also consulted the North Carolina Residential Building Code for the requirements for decks. | Top | Table of Contents | FINDINGS AND CONCLUSIONS Nine of the 14 posts in the lower and upper decks fail because they are either undersized or improperly braced against lateral displacement. The code requires 4x4 knee braces at every post that is over 8' high. In addition, knee braces must be attached to the posts at least 1/3 the distance down from the tops of the posts. The perimeter bands on the lower deck are not properly attached to the posts. The code requires bolted connections when the posts are attached to the sides of the bands. The 2x8 joists supporting the upper deck are undersized. They fail in bending, shear and deflection by a substantial amount. The 2-ply 2x8 girder supporting the upper deck is undersized. It seriously fails in bending, shear, and deflection. Since this is a principal supporting member, the deck could fail suddenly. Since the deck is 10' high, there is a potential for serious injury. The 2x8 bands (spandrel girders) supporting the upper deck are undersized. They fail in shear and bending. The decking planks on the upper and lower decks are okay. The 2x10 joists supporting the lower deck are also okay. The deck does not need to be torn down. It can be salvaged if major structural modifications are made, especially to the upper deck. The estimated cost of repairs is $3000. Until the repairs are made, the decks should not be used. | Top | Table of Contents | LIMITATIONS The observations described in the report are valid on the date of the investigation and have been made under the conditions noted in the report. We prepared the report for the exclusive use of Residence Inspectors Group and their successors and assignees. Criterium-Stanton Engineers does not intend any other individual or party to rely upon the report without our express written consent. If another individual or party relies on the report, they shall indemnify and hold Criterium-Stanton Engineers harmless for any damages, losses, or expenses they may incur as a result of its use. The inspection is limited to the visual observations we made during our inspection. We did not remove surface materials, furnishings or equipment, undertake any digging or excavation, or perform any destructive or invasive testing. Accordingly, we cannot comment on the condition of systems and components that we could not see. In addition, we are not responsible for conditions that were not within the scope of our services at the time of inspection. We did not assess the stability of the soil since this effort would require excavation and destructive testing. We did not perform a comprehensive code review. This report should not be considered a warranty of condition, and no warranty is implied. The costs that we have given to remedy deficiencies are estimates only. They are based on our general knowledge of building systems and the construction industry. Costs may vary significantly from estimates and competitive quotations from repair contractors. | Top | Table of Contents | William A. Stanton, P.E. | Top | Table of Contents | | Structural Inspections | Residential & Commercial Services |