“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

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Just A Handful Of Nails? On A Million Dollar House? Are You Kidding?

 

Just A Handful Of Nails?   On A Million Dollar House?

Yup! A handful of nail is the answer to “what’s holding the deck on?”

That’s pretty shocking on a building valued at a million plus. The nails are Ramset type, a heavy duty concrete nail that is shot into place with a 22 cartridge. They are thick and hardened to do this but they are not for permanent use out doors. The will and are rusting.

They are not made to transfer weight, and certainly not live loads like people walking on decks. They are made to attach wood framing to concrete but the framing (vertical) parts are supposed to carry the weight.

ledger

In the photo above the ledger is ‘shot’ on to the brick. This is not a brick wall. It’s a wood framed wall with a single facing layer of brick (called veneer) on the outside. So if lateral (sideways) forces move this building (earthquake) there is a real risk the ledger will be pulled from the wall, collapsing the deck. (The bricks will just come with it.)

The 2×4 support blocking show above that has been placed to stiffen and support the deck ledger. It has only 2 nails in the concrete. The difference between that an a pair of cinch anchors or through blots is huge and they can be had galvanized or in non-rusting alloys.

The other thing to take note of here is that it’s only the edge/end of 2×4 pieces (several along the length) that reinforce the the ledger. Lateral movement of only 1.5 inches means the deck will fall.

 

The photo below is the doubled beam the supports the outer half of this deck. Structurally for weight transfer everything is good but there are some issues.

In this part of the continent we are averaging earthquake shock roughly every five years. This can’t be predicted of course and they aren’t major, usually less than 5.0 on the Richter scale.

That’s nothing like what the west coast experiences and most people don’t even notice. But your house does.

beam

So the issues are;

A The bracket on the concrete support is small and hasn’t much grip on the beam. There are 4 small screws holding it and they are less than an inch from the edges of the wood beam. Gravity is doing the rest. There is some surface rust to be taken care of (rust paint).

B There is no blocking or bracing to prevent this beam from rolling over. This can easily be done with wood or metal parts. A few years ago here in Quebec a roof collapsed on a commercial building and employees were killed. Investigators found that the trusses did not fail or break, they just rolled over and collapsed. Bracing was mostly absent.

C The deck joists have no blocking or x-bracing (at the mid span) so they will be a bit bouncy under live load (people) and also risk rolling over.

Just picture a bunch of partying friends line dancing to “The Rocky Horror Picture Show” and all ‘jumping to the left’ in unison. Not the ‘smashing‘ party you want to envision.

Now this is not an emergency. Things will hold together for a while but it needs to be corrected and it wont cost a lot, but on a million dollar house, it should be there.

 

So when you need a full inspection………………….

 

 

 

Original blog post on ActiveRain: Link to Blog Post

QUESTION ANSWER & RESPONSE ; An FAQ for YOU

 

Question Answer & Response ; An FAQ for YOU 

 

The Question;

 I am most interested in asking you some more precise questions… for example, the back porch, you mentioned it needed securing. (the rail) can you suggest how that would be done if we get a handyman?  I am concerned how to do it properly as last summer I inquired and the guy didn’t know how to do it, and felt it was o.k..  I had called because I thought it was wobbly. You mentioned how you would see it best done. Please recommend, so I can proceed accordingly with my sister’s handyman. I am cc’ing her as well. I thank you..and look forward to communicating with you again for other questions pertaining to your recommendations. D.

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The Answer;

Hi D,

That centre deck post is mounted on top of the deck and secured with a bunch of small brackets. This is wobbly as it depends on the screws which are small.

 

 

(1) Restructure: The correct way to build this detail would have been with a longer post that passed down through the deck and was integrated with the support structure below. This is carpentry and you need a repairman with that experience and training.

 

(2) Hardware Bracket: Another way to ‘fix’ the situation would be to replace the brackets with a much more substantial heavy duty bracket that could hold the post rigidly. This is hard to achieve as the length of the post results in a big mechanical advantage when someone leans against the railing. Effectively the post acts as a lever against the bracket, loosening it.

 

(3) Stiff Back Reinforcement: The handrail could be modified by attaching (bolting and lag screws  – do not use deck screws) a wide 2×6 or 2×8 board on top of the handrail and flush to the inside edge. The wider the board the stiffer the rail will be. This has to be a single board for the whole length of the handrail and has to be installed with any crown inward (and cup downward) and the edge ‘fitted’ to the existing railing as each bolt hole is drilled and the bolt attached.

 

This is the easiest way to correct the problem and gives a nice wide rail to rest drink glasses on or place decorative plants or other ornamentation. For appearances the same detail would be done at the side railing returning to the house wall. A strap corner bracket would be installed at the corner to prevent it from opening over time. At the posts and mid-span points of the railing wood blocking would be screwed in place underneath to counter the wider boards tendency to cup (warp).

 

Again this is carpentry that requires a full understanding of wood technology. If your handyman doesn’t understand why the board has to be full length wide 2x stock with the crown in and the cup down then you need somebody else. The correct hardware and installation process is important too. The board should be preselected at the suppliers too.

Maintenance: You can see in the photo how snow (and rain water) will sit on the railing. It will be even more with a new wider railing top, so the board should be installed with a slight angle to shed water and of course be sealed to resist water penetration.

 

Should you need a referral for someone to do this please feel free to contact me.

Regards,

 

Robert Butler

 

 

 

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The Response;
Thank you kindly for your detailed reply.  I would appreciate a referral for this work if you please.  Thank you. I am glad to have found you as a resource!  D.

 

 

 

 

 

Original blog post on ActiveRain: Link to Blog Post