Supporting the house while a rotted beam is swapped out in Vanier?

Swapping a rotted beam while the house stays standing is a sequencing and planning problem, and the carpenter and designer need to work that out together before any wood comes out.

The first thing to settle is where the load goes while the old beam is out. That depends on what the beam carries, how far the load travels down to the foundation, and what the floor and ceiling framing looks like on either side. The designer and carpenter plan where temporary supports go based on that picture, not on a general rule. If the beam sits in a masonry or concrete pocket at or below ground level, the Ontario Building Code (2024, O. Reg. 163/24, clause 9.23.2.2.) requires the end to be either treated against decay or separated from the masonry by at least a 12 mm air space, so the replacement beam has to meet that condition too.

The new beam itself gets sized by a qualified, registered designer (BCIN), an engineer or an architect, or by you for a house you own. The Building Code Act (s.15.11(5)) sets out who may prepare design documents submitted with a permit application. Many beam replacements of this kind are designed by an engineer or a registered designer; ask the City of Ottawa (Building Code Services) what it will accept for your specific situation. The City's permit list includes structural repairs and alterations, so confirm with the City before the old beam comes out.

A fair quote for this job itemises each of these steps as its own line:

• design (sizing the replacement beam and planning the support)
• the building permit
• temporary support (location and method, as the designer and carpenter plan it)
• materials (the replacement beam, any hardware, treated ends or air-space blocking)
• labour
• patching and finishing once the beam is in
• disposal of the rotted material

If the house was built before 1960, Health Canada notes that lead-based paint and materials that may contain asbestos, including plaster and older finishes, are a real possibility. Ask the carpenter whether testing is needed before anything is disturbed.

Before you agree to anything, ask the carpenter to name the designer who will size the replacement beam and confirm that person will be on the permit application.