OpenWall

Important safety & design notes

Please read these before any work begins. They apply to every design this tool produces.

What this design assumes

• The opening is inside the building, in a wall carrying floor loads only — not a roof, snow, deck or garage load.
• Loading is ordinary residential: 0.5 kPa dead load and 1.9 kPa live load. Tile, stone, masonry, water features and unusually heavy finishes are not covered.
• The wall carries gravity load only. It is assumed not to be a shear wall and not to provide lateral, wind or earthquake resistance.
• Lumber is SPF No. 2 grade or better; steel is CSA G40.21 350W.
• The structure below the opening — existing beams, columns, walls and footings — has enough capacity for the added load. This tool does not check it.
• Soil under any new footing can carry the bearing pressure entered. No soil testing has been done.

Before and during construction

• Temporary shoring is required. The existing structure must be properly supported before any part of the wall is removed. This is the contractor's responsibility.
• Verify every dimension on site. Do not scale drawings.
• Provide minimum 89 mm (3½") bearing at each end of the new beam.
• Where a new column passes through a floor without landing on an existing beam, carry it continuously down to the basement slab or a new footing. Keep wood clear of moisture.
• New footings must bear on undisturbed soil. Stop work and get advice if you find fill, soft ground or water.
• A building permit is normally required. Check with your municipality before starting.

Stop and get professional advice if

• Anything on site differs from what you entered here.
• The wall supports a roof, a stair, a bearing point from above, or an engineered floor system.
• You find cracking, sagging, rot, insect damage or previous alterations.
• The building is older and may contain asbestos or lead — these must be assessed before demolition.