Carried And Through: ……Bolts Out Of The Blue

Carried And Through: ……Bolts Out Of The Blue

Jay Markanich’s recent blog raised a debate about the use of carriage bolts in outdoor wood structures. Some appear to claim that they are an inferior fastening technology. I say consider the source.

Some facts: Carriage bolts were designed to be drawn into the wood to lock the head in place and allow tightening of the nut. That system works fine as long as the bolt holes were not too big in the first place and as long as the heads don’t slip when torque is applied.

This is ‘the carriage bolt school technology‘ and it is quite sufficient for the weight and stresses that these structures are subjected too. A little maintenance is required over time to retighten the bolts and keep water out of the head area. Water entry at the head area can degrade the wood there, but it would have to be extreme for the connection to fail.

Simpson Strong-Tie people are selling a product. From a strictly engineering standpoint more torque can be applied to a properly washered through bolt. In theory the joint can be clamped tighter, but both bolts have the same load carrying strength for their size.

So through bolts can be made tighter and as their installation does not involve crushing wood fibres they have lesser incidence of wood deterioration risk around the heads (Note that they do have some, just not as much risk).

Technically the Strong-Tie sales peoples claim that their opinion about through bolts being better is supportable. But stating that carriage bolts are categorically inferior is pushing it. Remember they are selling a product they believe in so a little bit of overstatement is forgivable.

Carriage bolts properly installed and maintained are fine. Suitably large bore washers can be installed under the heads if the wood species is problematically soft or constantly wet.

Carriage bolts have the advantage in that the heads are smooth low profile forms that do not protrude to skin shins or knuckles and catch on ropes.

Carriage Bolts….carry on!

 

 

This article was written by Robert Butler and was inspired by the original blog article mentioned above by Jay Markanich and written in part as a comment on this follow-up blog. Link through to these blogs for other opinions and more discussion on the subject.

N.B. This might seem as a serious debate and it is to a point. Both products and systems are structurally functioning methods. The debate is really about degree and longevity.

Contrast that with the frequently discovery of structures built with out benefit of either fastening system. This is where Jay’s original blog and indeed most blogs on the subject stem from.

 

 

 

 

Original blog post on ActiveRain: Link to Blog Post

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Don’t Trim Those Toe Nails!

This is a serious problem that is prevalent because of amateur or un-informed workmanship. The only railing systems that can be attached onto the deck surface are solid metal types designed to be surface mounted. All wood systems have to pass through the decking and be through bolted into the framing.

This article is written by an experienced Virginia inspector. His tone is a bit sarcastic but he illustrates the point very well.

Toe nailing is a valid carpentry technique.  But for the most part it is a temporary tacking of one thing to another by nailing two things together at an angle.  Then proper attachment can be made.  Toe nailing is seldom, if ever, intended for long-term attachment or support with heavy material.

Walking around this deck, only about 4′ high, I noticed that every single guardrail post had been toe nailed to the decking!

Don’t trim those toe nails!

You can see how substantially attached that post is to the deck (he sarcastically notes).  Many wobbled a lot!  Rock on dude…

Despite the VERY FINE paint job, this is a huge problem.

Sure, the deck is only 4′ high.  Do you want to fall 4′, land on top of a broken guardrail, and land at an angle you can’t control?

Didn’t think so…

Where do people end up when they go out onto a deck?

The guardrail!  They lean.  They put weight.  They ASSUME it’s safe.

The code would like the guardrail to easily support about 200 pounds.  That is all well and good.  But often more than one person is leaning against the rail!  Remember, the code is a MINIMUM STANDARD!  And a well-attached, or properly-attached, post can support far more than 200 pounds.  How should deck posts be attached?

There are various ways.

They can be attached on the outside of a joist, or the inside.  Two can be attached surrounding a corner.

BUT ALL MUST BE ATTACHED WITH TWO THROUGH BOLTS THAT ARE SEPARATED FROM THE WOOD WITH LARGE WASHERS.

The bolts, washers and nuts should be of the same material that resists corrosion (stainless steel, galvanized or zinc dipped).  The most common would be galvanized.

Carriage bolts are not good bolts to use!

Why?

The round head is not wide enough and when the nut is tightened the round head actually gets sucked into the wood.  And the square end under the round head does not accept a washer.  Carriage bolt use was emphasized by the engineers at my recent Strong-Tie seminar.  Carriage bolts should not be used for post or beam attachment.

There are other criteria regarding guardrails that are important, but not the point here.

Proper attachment affords strength and safety.  Safety is always the bottom line.

My recommendation:  when you see a deck, have a look!  Feel its strength as you walk on it or carefully lean on the guardrail.  Check attachments.  How does it make you feel?  And get an inspector to have a look see should you put a contract on the house!  Decks COMMONLY have problems.  You want to know what they are!

 

Jay Markanich Real Estate Inspections, LLC

Based in Bristow, serving all of Northern Virginia

www.jaymarinspect.com

 

Original blog post on ActiveRain: Link to Blog Post

Do You Ever Have That Sinking Feeling?……………………….An OMG FIle.

 

Do You Ever Have That Sinking Feeling?……………………….An OMG FIle.

Do you ever feel like you are just floating along, not connected to any thing. Not grounded. Well you might not be if you are on a deck like the one shown below.

deck supports

You can see that the support beam that’s been added to this deck at mid-joist span to support and stiffen it. It is doing neither. It’s not even touching the joists or the footing post below itself.

It could be removed and it would have no effect on this deck. You’d never know it was gone.

Usually as support beam is larger than the joists it is supporting (or supposed to be supporting). This one IS a double thickness built up beam, but it’s 2/3s the size of the joists. The original joists and decking are pressure treated.

The footing of course is the floating type on the surface of the ground. That means it’s going wherever the frost takes it. So this deck will be having its ups and downs. A footing below frost depth is the only thing that is stable in this climate.

So you can see that nothing is touching here like it should be. You can also see there are no connectors. No nails, no screws, or no brackets.

Footings and foundations for buildings and structures, like decks, that are not anchored below the frost depth are described as floating footings.

In this case the structure might be more accurately described as flying rather than floating.

 

So when you buy a home you want to know you wont be sinking under repair bills. Get a full professional inspection.

 

 

 

Original blog post on ActiveRain: Link to Blog Post