Six Retrofit Mistakes to Avoid
The following are common mistakes we see during retrofit construction. Also, a reminder that no construction should be started until the homeowner has received EBB's approval to begin.
#1 Incorrect Bolt/screw end distance in mudsill
#2 Nails overdriven or misplaced
#3 Bolts and nuts improperly installed
Bolts should be straight and all nuts should be tightened as per manufacturer specifications
Bolts should be flush with the top of the nut
#4 Use of non-approved angles, hold-downs, clips and foundation plates
No work is required at the interior of the crawlspace. Hold-downs are always located at the ends of shear walls
Vertical angles have no lateral capacity and are not required by Chapter A3 or the plan sets. Note: the requirements for foundation plates include a minimum plate thickness, 2-1/2” diameter anchors and 3-1/4” diameter lag screws
#5 Cripple walls >4’-0” must be designed by an engineer or using FEMA P-1100
Walls greater than 4’-0” require special attention as they may require hold-downs at each end.
Chapter A3, Plan Set A and the LA Standard Plan Set all require an engineered design for walls greater than 4’.
Check with the building department to see if they allow use of FEMA P-1100.
#6 Only Use Manufacturer Specified Concrete Anchors in Prescriptive Hardware
Mitek SRC Requires PowerStud® anchors
Prescriptive hardware such as the SRC or URFP must be installed per the manufacturer’s requirements unless a registered design professional specifies the anchor.
Simpson Strong-tie URFP requires SET-3G, AT-XP, or Titen HD
Check the manufacturer’s requirements for approved concrete/masonry anchors.
(Note: LA Standard Plan Set #1 requires all anchors have current LARR approval.)
✔ Cripple Wall Bracing
✔ Foundation Repair
✔ House Bolting
✔ Shear Walls
✔ Crack Repair
✔ Foundation Replacement
✔ House Leveling
✔ Soft Story Retrofitting
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Bolt Down LA
9909 Canoga Ave. Ste. G
Chatsworth, CA 91311
Phone: (818) 306-2233 or
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