A Case Of More Not Being Stronger..A Stair Story.

A Case Of More Not Being Stronger…..A Stair Story. (This is # 4 in a series on a single flipped house.)

   nailed stringer L   nailed stringer R  

These stringers have been nailed to the deck framing with a power nailer. An air powered nailer is a great tool. It allows you to drive large nails without tiring you out. So if you want another nail there , it’s just pull.. BANG and it’s in there. And there’s the problem!

Before the common use of these tools that extra nail took some more effort. Sore arms generally set limits on the number of extra or unnecessary nails being driven.

Carpenters had code books, charts and rules that governed the type, size and number of nails used for any type of joint and size of framing. And they learned this though years of apprenticeship and work practice, training and exams.

But even carpenters had to be cautioned when these tools went into widespread use as it’s too easy to use the wrong size nail or put too many in the same area.  And Codes were changed to correct bad habits and practices.

But on this flipped property this is amateur work. No carpenter puts that many nails in this area, let alone both faces of the same piece. On the end of this stringer, in the last 2 inches of wood, how many nails are there? How much solid wood is left, wood that is not split by a nail or two?

There are too many nails (12). They are too big. And there is no solid wood left in the last 2 inches of the stringer. If you removed it and sawed it off at the 2 inch line, little scraps the size of your finger or thumb would fall to the ground.

Prior to the code changes larger framing (deeper) was required to butt the stringers against as a ledger strip had to be nailed. The ledger strip required a triangular nail pattern using nails larger than 4 inches and that required a doubling of the bearing frame.

Then the stringer was notched to bear on the ledger strip (this is where the weight was transferred) and a stringer this size would be nailed like this with two nails on one side and one in the center on the other face. The nails would be galvanized 2 or 2 and 1/2 common. (This is toe nailing, through nailing from the other side of the support frame is better.)

Nails hold the framing in place. The framing configuration transfers the weight. Nails normally are not intended to transfer weight. (The ledger board detail was an exception.)

Now the current codes treat this differently. Correctly sized metal  joist hangers are to be used. Galvanized nails can be used to mount them. Deck or outdoor screws are NOT to be used between the hanger and the supported framing – that has to be nailed – It’s a fire code requirement.

Now look at these photos again. There is no ledger strip. There are no joist hangers. The nails are too big. There are too many of them. They are not galvanized. There is not enough solid wood there to hold these stringers in place.

What keeps it from collapse?

Gravity!

Just like a ladder. And just like a ladder, a side ways push or the base sliding out will cause it to fall. Are the stringers attached to anything at the bottom?…nope!

More nails is not stronger. To many is weaker.

 

 

Original blog post on ActiveRain: Link to Blog Post

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

“Faulty Towers”…..Funny, Faulty Decks………Dangerous !

“Faulty Towers”…..Funny,       Faulty Decks………Dangerous !

Faulty Towers was a hilarious British comedy. it was a sit-com staring one of the founding members of ‘Monty Pythons Flying Circus’.

Faulty decks though that’s a different kind of story, and if you are unlucky it’s appearing on a balcony or deck near you.

Take a look at the example below and remember just because it’s been there for a while doesn’t mean that it always will be (there).

deck defects

At ‘A” you can see the short remnant of the original cantilevered beam built into the original floor framing of this building.  The joists of the current construction are sistered onto either side. This is nailed with 4″ common nails, not galvanized.

B” Is the top end of the diagonal brace, a 4 by 4 bracketed by the sistered joists mentioned above. The same type of nails are used, but smaller ones.

C” the base of the same diagonal brace is set into a shallow pocket in the cement bonded stone foundation wall. There is a horizontal steel pin, basically a spike nail pining it from moving.

So whats wrong with that you say?

Well: Nails are just pins that lock things in place . The weight transfer has to be wood resting on wood.

Nailing wood the side of another wood member without notching it in to support it from underneath means the weight transfer is being done on the nails. Nails can not resist the stress over time.

They seem to work when everything is new and tight. Then things get a bit loose and flexible. For a while there is a little ‘wow’ deflection felt. It can last for years. You’ll even forget about it. “Oh, it’s OK, it’s aways been like that”.

The nails loosen from wood shrinkage, wood degrades from water exposure and nails rust, loose diameter and loose their hold strength.

Then one day it’s not OK. Gravity wins, you loose.

At ‘C‘ water collects here, keeping the wood wet, slowly rotting and the spike nail rusting.

To be safe:

A and B have to be bolted though with non rusting blots that pass through all the wood members and clamp them together. The number an spacing have to be staggered to prevent check splitting down the length of the grain.

C needs a rust proof bracket that holds the wood brace end off the stone to allow it to dry after rains and holds it securely on the stone foundation with through bolts. Lag bolting and cinch anchor bolts cannot be guaranteed to work on all kinds of stone.

Now look around the corner to this part of the structure:

ledger defects

Here we see some of the more common problems with decks.

The ledger board (against the wall), has no flashing and only has two (E) lag bolts set in mortar.

Now look at where the joists join onto the ledger (D). You can’t see the nails because they are very small. There’s only 5 of them and they are not galvanized.

To be safe; The ledger board has to be solidly attached. That means at least 5 bolts in this much space.

Ideally the bolts should be through bolts but if the stone is too friable then shorter lag or cinch anchor bolts can be used provided they are doweled into the stonework with epoxy. Of course they have to be galvanized or made of non-rusting alloys.

I’ve seen some amateur use of tapcons here (cement or masonry anchoring screws). They should never be used – they have even less shear strength than nails. They fail by just breaking off. The metal is not strong enough.

The ledger has to be flashed to keep it dry or wood rot decay will be a problem. Don’t count on pressure treated wood to be sufficient. Remember you are not building for the weekend or just the next ten years, you’re building for forever.

Lastly; Joist hangers – the proper type will not rust and each joist will be secured with 14 nails not not just 5 ‘toed’ nails.

DO NOT use screws at any structural joints including joist hangers or any other bracket that transfers weight. 

Fire code requires that all structural weight bearing or transferring joist brackets (and other similar hardware  attachments) be only attached with nails (not screws or ring shank nails).  This is for the safety of firemen so that when floors burn through, the joist and other horizontal timbers be allowed to release and fall without pulling down the walls on top of the firemen. Screws disrupt that release.

 

So if you’re looking at property anywhere in the Montreal area and you need a full inspection…………

 

Original blog post on ActiveRain: Link to Blog Post