Should I use engineered lumber or dimensional lumber for my Ottawa addition?

Choosing between engineered lumber and traditional dimensional lumber affects structural performance, cost, schedule and how the addition behaves over its first few winters. Both have a place in residential construction, and understanding their strengths will help you have useful conversations with your designer and contractor.

Dimensional lumber is solid sawn framing, such as 2x6, 2x8, 2x10 and 2x12 boards from spruce, pine or fir. It is the traditional choice for residential framing and remains well suited to most addition walls. It is widely available, easy to cut and fasten on site, and well understood by framing crews. For wall framing, there's rarely a strong reason to choose engineered products over standard studs.

Engineered lumber includes laminated veneer lumber (LVL), I-joists, glulam beams and laminated strand lumber (LSL). These are manufactured by bonding wood veneers or strands under heat and pressure, producing members that are straighter, more consistent and more dimensionally stable than solid wood of the same size. They shine in floor systems and long-span beams. An LVL beam can carry an opening that would need a much larger solid wood header, and I-joists give consistent performance without the crowning, twisting and shrinking that sawn joists can show.

For floors, many builders prefer engineered I-joists, especially on longer spans, because they make flatter, quieter floors that are less prone to squeaks. Whether a sawn joist or an I-joist suits your span depends on the load and spacing, and your designer will size them from span tables or the manufacturer's literature. I-joists usually cost more per piece, but they can be quicker to install and can reduce problems during drywall and flooring.

Dimensional stability matters in a heating climate. Over the first heating seasons, solid wood dries and shrinks, which can show up as nail pops in drywall, squeaky floors and gaps at trim. Engineered products move less. That's especially relevant where the addition joins the existing house, since new framing shrinking beside old framing that stopped moving long ago can cause cracks at the junction.

The Ontario Building Code (OBC) accepts both kinds of lumber when used within their design capacities. Engineered products must be installed to the manufacturer's instructions, including rules about holes, notches and bearing. That matters for plumbers and electricians, who can't drill engineered members the way they might drill sawn lumber. Ask your contractor to keep the manufacturer's installation guide on site.

A common approach is a hybrid: dimensional lumber for walls and engineered products for floors and beams. Ask contractors to price the framing package both ways so you can see the difference for your addition, rather than relying on a general figure. You can browse addition contractors in the Ottawa Construction Network directory and compare itemized quotes.

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Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:

• Homeupgraders
• JC Carpentry
• Geerts Roofing Inc
• Renovo Construction
• Dreamwood Construction & Renovations