ud83dudcda Wood Deck Build Log u2014 20 of 45
u2190 Detail #4: Main Beam First Calc u00b7 Series Index u00b7 Detail #6: Main Beam Redesign (Revised) u2192
2026 Update from DIY Dad: Detailed Planning and Construction Prep
ud83duded2 RECOMMENDED PRODUCTS
Pressure-Treated Deck Lumber
Pressure-treated lumber is the baseline u2014 skip it and you’ll be rebuilding in 5 years.
Once the overall structure was set, the focus shifted to detail design and construction preparation u2014 working out all the joinery and finalising the materials list for ordering. ^ ^
Tools You’ll Need for a Wood Deck Build
- Circular saw (cutting lumber)
- Impact driver (screw fastening)
- Spirit level (levelling the footings)
- Laser level (establishing the datum line)
- Clamps (temporary holding)
- Square and tape measure (checking dimensions)
Hardwood is extremely dense u2014 always pre-drill before driving screws. Skip the pilot hole and the screw will snap or the wood will split. m(_ _)m
Main Beam (u5927u5f15) Redesign: Updated Load Assumptions
ud83duded2 RECOMMENDED PRODUCTS
Deck Stains & Waterproof Sealers
Stain every 2u20133 years. It’s the single cheapest way to double deck lifespan.
Hi, I’m DIY Dad. ^ ^
I revised the load conditions for the beam recalculation, making four changes:
- Loads from the decking boards and floor joists are distributed, not concentrated u2014 treat as uniform distributed load.
- Assume the floor joists act as rigid bodies, spreading the load evenly across all beams.
- Change the beam and joist orientation (swap x/y directions).
- Cantilever the decking boards beyond the posts to minimise the beam clear span.
u2191 Before revision
u2191 After revision
This relaxes the load conditions considerably. Each of the 3 beams now carries 240 kg u00f7 3 = 80 kg.
Maximum clear span L = 2,300 mm.
Revised Calculation
u03c9 = 80 u00d7 9.8 / 2,300 = 0.34 N/mm
M = u03c9Lu00b2 / 8 = 0.34 u00d7 2,300u00b2 / 8 = 224,825 Nu00b7mm
u03c3 = M / Z = 224,825 / 2,990 = 75.2 N/mmu00b2 < 157 N/mmu00b2 u2192 OK
u03b4 = 5u03c9Lu2074 / (384EI) = 5 u00d7 0.34 u00d7 2,300u2074 / (384 u00d7 2.05u00d710u2075 u00d7 72,600) = 9.19 mm > 7.7 mm (L/300) u2192 NG
Stress is now within the allowable limit. Deflection slightly exceeds u2014 but I’m going to let that slide for now. ( u02d8u03c9u02d8 )
That’s all for today! (^^)/~~~
ud83dudcda Wood Deck Build Log u2014 20 of 45
u2190 Detail #4: Main Beam First Calc u00b7 Series Index u00b7 Detail #6: Main Beam Redesign (Revised) u2192
DIY Renovation Quote Review Manual
How to read, compare, and negotiate contractor quotes. This manual saved me u00a5800,000 on a single renovation project.
ud83cudfe0 More from DIY Father
15 years of landlord experience u00b7 3 apartment buildings u00b7 DIY renovations that saved millions of yen. Browse all articles at diytosan.com
