Stability Engineering – Structural Engineering Services

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Considering A Second Story

Here are a few things to look at when you are considering a 2nd story addition:

Condition of the Homes Foundation
1. Cracked foundation walls and masonry stair-stepping.

2. Footing conditions. Although the existing footings for house could be suitable for the existing footings. The addition of an extra floor load could permanently damage the existing footings. Additional footings may be required adjacent to the existing. Look for piers that are leaning, cracking, rusting or settling, deteriorated mortar.

3. Basement wall retaining: Beware of basement walls that are cracked and bowing. This could be a signal that the wall is not vertically reinforced. Look for horizontal cracks at wall mid-height

4. Site retaining wall. Concrete and masonry retaining walls are designed to last over 50 years, but timber retaining walls generally have a lifespan of less than 25 years. All of them are subject to environmental damage from moisture exposure to slope failure. Look for wood rotting, rust stains and surface cracking from exposed rebar, evidence of sliding from addition of surcharge, improper footing depth and inadequate wall drainage.
Framing Conditions
1. Basement beams may be undersized or in poor condition. The additional load of a new 2nd floor addition depends on the support of the 1st floor or crawl space framing. These members could be overstressed due to over spanning, improper bearing, moisture damage or termite damage. Look for floor warping, dipping, hardwood flooring spacing and door misalignment.

2. Existing window headers: The existing house may lack proper header beams over the windows and doors, especially in houses built prior to the 40’s.

3. Shear walls: Structural walls must be present in both directions to prevent racking of the structure. This becomes a major issue when adding an additional floor and adding openings to the1st floor, since the wind loads will be transferred to the foundation through these walls.