How strong is one nail?

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1

Originally Posted By: pdacey
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There are 3 beams supporting the roof over a carport. All three terminated at the house like this one. Note the single nail in the ledger piece. They have been in place for at least 10 years.


[ Image: http://www.nachi.org/bbsystem/usrimages/I/IMG_4414.JPG ]

--
Slainte!

Patrick Dacey
swi@satx.rr.com
TREC # 6636
www.southwestinspections.com

2

Originally Posted By: lkage
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icon_eek.gif


Roofers: Keep your workman’s comp. paid up!

–
“I have never met a man so ignorant that I couldn’t learn something from him.”


Galileo Galilei

3

Originally Posted By: awalters
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“Due to cut cut backs at Simpson Strongtie, this is all the new engineers could come up with”

4

Originally Posted By: rzimmerman
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Patrick,


It looks like there are toe nails in the side of the beam. I can see two. I would guess the small, single nail boards were used simply a another hand during install. A way to keep the beam in the right location till properly secured. I have done the same in the past when working with limited help. I bet the small board could have been removed after install.

–
Rob Z.


www.RZinspections.com

5

Originally Posted By: ccoombs
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“How strong is one nail?”


This is a very difficult question to answer...way to many variables.

On average, you are looking at about 100 lb per 16d sinker (also known as a 16d short). A toe nail condition is 50% of the nails normal value.

6

Originally Posted By: wpedley
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If it doesn’t go into the wall and the block is


the only thing supporting this it's WRONG. ![icon_eek.gif](upload://yuxgmvDDEGIQPAyP9sRnK0D0CCY.gif)

--
BPedley
Inspecting for the unexpected

7

Originally Posted By: pdacey
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Robert,


Yes I did note the two toe nails. They are only on one side of the beam. I still recommended that hangers be installed.

--
Slainte!

Patrick Dacey
swi@satx.rr.com
TREC # 6636
www.southwestinspections.com

8

Originally Posted By: rzimmerman
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pdacey wrote:
Robert,

Yes I did note the two toe nails. They are only on one side of the beam. I still recommended that hangers be installed.


Good Job ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

--
Rob Z.
www.RZinspections.com
9

Originally Posted By: ccoombs
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Patrick


I agree with you. No mater how much load the one nail can carry, it is wrong. I guess I should have stated that in my post. Thanks for covering my back on that one.

Curtis

10

Originally Posted By: roconnor
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. It could have been pushed to the limit over time, deteriorated by the elements, repeatedly weakened by prior loads, and is presently just barely hanging on by a thread.


Just my opinion and 2-nickles ... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong

11

Originally Posted By: pdacey
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Thanks Robert. Good advice.


This house had many issues. The buyer was looking at it as an investment property that she will be renovating.

--
Slainte!

Patrick Dacey
swi@satx.rr.com
TREC # 6636
www.southwestinspections.com

12

Originally Posted By: pbennett1
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How much difference is there?

13

Originally Posted By: dedwards
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How many times have you heard the statement. “It was working just fine when it quit” It almost always is.

14

Originally Posted By: mcyr
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icon_smile.gif icon_smile.gif



Thank God for no snow in that part of the Country.

The nails visible are producing about 250# each in shear. Barely enough for the dead load.
Marcel

15

Originally Posted By: rcooke
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One nail can cost a war.


http://www.geocities.com/EnchantedForest/Fountain/5540/Forwantofanail.html


For want of a nail

the shoe was lost.
For want of a shoe
the horse was lost.
For want of a horse
the rider was lost.
For want of a rider
the battle was lost.
For want of a battle
the kingdom was lost.
And all for the want
of a horseshoe nail.

--
Roy Cooke Sr.

http://Royshomeinspection.com

16

Originally Posted By: jmurphy1
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How strong is one nail? I don’t know but I think a screw is stronger.


Tapcon 3/16 or 1/4 screws in block or concrete are supposed to support up to 400 lbs per screw.

17

Originally Posted By: mcyr
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icon_smile.gif icon_smile.gif


Are you talking about the tapcon in shear or pullout factors?

I think a hardwood wood peg is stronger in shear. Tapcons are brittle and fail in shear and torque of installation. Also most time it is installed wrong.
Tapcons need impact as it is being driven to be the most effective, but not to driven, very hard to control the shear stress exerted on the fastener.

Regular nail well driven to most accept the load exertion, would surprise most people.

No doubt in my mind, the the issue at hand, needs expert evaluation as I would recommend.

Marcel

18

Originally Posted By: lgoodman
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A couple of years ago our local builder got a pamphlet from the nail mfr. and we were all surprised to see the 16d common nail listed for 325 pounds for shear. But we were totally surprised by their admonition that cement coated nails were not to be counted for any shear strength. No weight is allowed to be hung on c.c.nails alone. They are engineered for withdrawal resistance and not shear. The cement is actually vinyl which melts by friction and then permeates the little cell spaces and cools hard.

19

Originally Posted By: roconnor
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lgoodman wrote:
A couple of years ago our local builder got a pamphlet from the nail mfr. and we were all surprised to see the 16d common nail listed for 325 pounds for shear.

Definitely sounds high, as a 16d common nail with adequate penetration in good wood has a shear capacity of about 110 pounds. Maybe they listed the ultimate failure capacity, without any safety factor or reductions to consider things like uncertainty of loads, wood defects, or deterioration over time.

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong
20

Originally Posted By: mcyr
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icon_smile.gif icon_smile.gif


This might answer the question.

Hopefully it was written up properly and not have to be so technically correct.


On occasion installers will use whatever nail they have in their nail pouch to fasten the connector. Or, if they look at the specifications and see ?common? nail might assume that a 16d sinker or gun nail with a similar size designation is equal to a 16d common nail.

Catalogs from the major connector suppliers include instructions to the installers cautioning them about making fastener substitutions. Since the default specification is for common nails and common nails are seldom ?commonly? available, one cannot assume that the installer will even have the correct fastener on the job site, let alone be certain to use it. The catalogs include information on how to adjust for fastener substitutions, but these charts may not be available at the time the connectors are installed.

It is critical that the installer understands that all the specified fasteners may be required to achieve the design capacity. The load capacity for each 16d common nail in DF/L is 134 lbs. A total of 20-16d common nails are specified (20 x134 = 2680 lbs). If more than one nail is omitted, the connector will be overstressed because too few fasteners were used.

If 16d sinkers are substituted for 16d commons, the carrying capacity is only 112 lbs per fastener (20 x3 112 = 2240 lbs). One can also use the reduction factor of 0.84 from a supplied table (2680 x3 0.84 = 2251 lbs). In either case, the connector will be overstressed because the wrong diameter fastener was used.

If the specified common nail is being driven into SPF instead of DF/L, an adjustment of 0.86 will have to be applied to the load (2680 lbs x 0.86 = 2305 lbs) because fasteners do not have the same capacity in every species of lumber. The connector might be overstressed and fail because it's being nailed into a different material than originally assumed.

If the member that the fastener is being driven into is thinner than 12 times the diameter of the fastener, an additional reduction needs to be taken into account using the following equation:



The minimum penetration of a 16d common nail is 12 x 0.162 = 1.94". If the member is a single 2x, the edge dimension is only 1.5". Thus, the reduction equation must be applied.



The load carrying value of each of the 16d common nails nailed into the single 2x is reduced from 134 to 103.6 lbs (20 x 103.6 = 2072 lbs). This situation might also be the cause of a connection overstress.


Marcel



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