Wood Deck Vol. 37: Structural Members (Beams, Girders, Rafters) Assembly u2014 DIY Dad's Renovation Log

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ud83dudcda Wood Deck Build Log u2014 11 of 19

u2190 Build #36: Floor Joists u00b7 Series Index u00b7 Build #38: Purlins u2192

u7acau30fbSee the complete Wood Deck DIY Guide

Originally published: 2020-10-13 / Revised: May 8, 2026

2026 Update from DIY Dad: Framework, Roof, and Floor Boarding Assembly

2026 Update from DIY Dad: Framework, Roof, and Floor Boarding Assembly

Most Important

ud83duded2 RECOMMENDED PRODUCTS

Pressure-Treated Deck Lumber

Pressure-treated lumber is the baseline u2014 skip it and you’ll be rebuilding in 5 years.

Amazon US u2192
Amazon Japan u2192

Once the foundation and framework are complete, it’s on to the roof assembly, then floor boarding. The shape starts to emerge and you get that feeling of “the end is finally near!”

Key Points for Polycarbonate Corrugated Roofing Installation

Secure adequate overlap (150u201400 mm or more)
Fix with dedicated screws (umbrella nails or poly-carb screws)
Seal ridge side and eave side (to prevent rainwater infiltration)
Rafter slope must be at least 1/50 (approx. 1.1 degrees)

If you’re sloppy with the edge treatment, it will lift in strong winds u2014check all edges after installation.

How to Lay Hardwood Decking

Pre-drilling is essential (drill 3 mm pilot holes)
Use dedicated stainless steel screws (iron screws cause rust and black staining)
Board spacing: 3u2014 mm (use spacers for consistency)
Trim the ends after all boards are laid u2014cut in one straight pass with a circular saw

Hardwood is very heavy u2014two-person work is the baseline.

Hi, DIY Dad here. Continuing the wood deck renovation series. Joists are assembled u2014on to the next! Now I install the beams, girders, and rafters.

u7acau30fbBeams and girders

u7acau30fbRafters

I was cutting the scaffold pipe with a manual pipe cutter. It takes an unbelievable amount of arm strength. After cutting so many, the cutter blade chipped! Normally you’d use a high-speed cutting machine for this.

u7acau30fbPipe cutter

With the rafters assembled, I load the SPF lumber for the floor and purlins on top to let them acclimate. That’s 70 pieces of SPF 2uff83u30fb 6-foot (including spares) and 20 pieces of SPF 1uff83u30fb 6-foot (including spares).

u7acau30fbSPF delivery/staging

I’d been storing the materials in the second-floor room, so I was really eager to get them out. They were quite a volume, and inside the room they looked even bigger. Once they were outside, the room felt massively more spacious.

ud83dudcda Wood Deck Build Log u2014 11 of 19

u2190 Build #36: Floor Joists u00b7 Series Index u00b7 Build #38: Purlins u2192

ud83dudcdd DIY FATHER u2014 PREMIUM RESOURCE