One Butt Ugly Deck!

Hey, the whole world knows about incorrectly finished decks thanks to this post.

Picky picky... if you want to see a butt ugly deck, you should have seen my deck after the first time I stained it.

Jay, the carpenter was only doing what his boss told him to do, use as much of the scrap as possible so that nothing would go to waste. Not one of the tradesmen was going to see it from where they lived.

I wonder what they were smoking when they built this one? 

Jury rigged. 

Right? That's what we call it. Jury rigged. And it makes me wonder what other part of the home are poorly put together. 

We call it Mickey Moused commonly, that was mickey moused. Very interesting.

Ahhhhhhhhhhh!!! That IS one BUTT UGLY Deck!!! I can't believe that this builder is actually making a living on this shabby work!

Jay, this is one thing the average buyer wouldn't even think to look at.  And another reason every home buyer should have a home inspection.

Unfortunately Jay, we can't draw diagrams here in this editor (or any that I know about).  

What I was talking about is cross bracing and solid blocking (also called cross bridging and solid bridging).

This is done at midspan or 8' intervals (along the length of the joists) and runs perpendicular to the joists. It consists of small pieces (2x2) or short pieces of joist size material nailed into the space between the joists to stiffen and brace the joists from lateral or roll over movement. (Keep your eye out for metal bar systems that were used in the 60s and 70s. They’re OK if they are still firmly attached. – no nails.)

For standard lumber stock (2" nominal, 1.5" actual), joists that exceed 10 to 12 feet in length (note-this is not the same as span) should have this bridging-blocking at the mid length position. This is the only way to absolutely prevent rollover failure.

Joist roll over failure occurs when the middle area and midspan zone of long joists deflect sideways due to loading or shock under load (earthquakes). The joists tip over sideways in one direction and then the load breaks the joists and the floor collapses. This also can occur in trusses and rafter systems.

Joist hangers and rim nailing or screw attachments at the ends can help but are not sufficient to prevent the roll over from occurring except in joist lengths of 8’ or less. The joist wood simply breaks at the hardware connections when rollover occurs.

Unfortunately this has occurred here in Quebec where a snow loaded truss roof system rolled over and caved in on an occupied building. There were multiple fatalities. The engineering report cited the rollover and collapse being caused by insufficient lateral bracing between the trusses. 

In floor and deck framing, that lateral bracing is the cross bracing and solid blocking. Decks have failed here this way but so far with out serious personal injury. (Visualize ‘Rocky Horror Picture Show’ fans all ‘jumping to the left’ in unison, on a deck without this detail. – From a framing perspective that constitutes ‘shock loading’.

Deck framing (rather than house floors) is more susceptible to rollover failure for three reasons;

1.    They are more likely to have been constructed by non-professionals who are unaware of the importance of this detail.

2.    Unlike house floor frames they are not contained or restrained on all sides by walls that could help prevent or limit any roll over movement.

3.    The ability of the joist to flex in the middle or deflect sideways under load is a function of its height to thickness dimension ratio. The nominal thickness standard is 2”. The actual thickness has decreased over time from 1-3/4” to 1-5/8” to 1.5”. However you can buy 1-1/4 stock and many ever budget conscious DIY builders, and low bid contractors, do just that. 1-3/8” is also common and nearly as flexible.

In this case flexible is not desirable, but good solid and safe decks can be build with these materials. But ‘to code’ is unsafe.

These builds have to be done with a full understanding of the first principles behind the code provisions. In other words the builders have to understand why these details are important, what difference the thinner stock makes and have the skill and knowhow to build well and safely with these materials.

As inspectors and real-estate professionals we have to be aware of the consequences of the absence of deck and other framing details. Be alerted by ‘new’ thinner dimensions and materials.

That's good Jay. Where do you find such diagrams? I know you could do it in Google Sketch-Up but that would take me weeks verses hours.

I deserved that! Must be tired. Cheers, RB