WOOHOO! Good weather = time to build

[MountainMan]

Oh noooooo! I had the blueprint upside down when I built the building!!! Does this mean I have to start all over?

Nope! Just move the roof!

[sgtcarl1]

Or maybe stand on your head alot!!!

[doctorwayne]

Thanks Tetters,

In the past, I had always assumed that the screws were better than nails. I thought that nails were used only because they were faster and cheaper. Now I am giving it more thought.
I wish I could find some actual engineering studies, because again, I don't think the "shear" is as important as some of the internet info makes it seem.

But dang it, you guys have me considering going back and adding nails in addition to the screws!!!!

Good stuff!

The material being fastened also plays a role in how well the fastener functions. Nails and screws are relatively easy to pull once you get a grip on them, with nails more-or-less being removed from the hole created by their installation and screws removing the material immediately around them. If you're installing a ringed flooring nail with a hammer, and for some reason (hit a water pipe ) have to remove the partially-driven nail, chances are it will either also remove the wood around the rings, much as a screw would, or the head will break off. A lot also depends on the metallurgical properties of the fastener, especially for screws - I've bought screws that were of such poor quality (one big guess where they were made) that the heads snapped off as the screw was being driven, or the material was so soft that the socket was mangled by the driver bit, even though the fit between the two was excellent. I've also had many instances where the screw will bend while being driven.
Most building codes have regulations governing lumber specifications (permitted spans, loads, live load limits, etc.) and also nailing "schedules" which specify how many of what type, size, and length of fastener are to be used for each particular application.

Wayne

[Gary S]

With my inquisitive nature, and with the longevity of my train building and layout at stake, I thought up several tests on the screws versus nails issue. I performed one of them tonight which, to my halfway scientific mind, tested the shear strength of the wood/fastener combination, since that is what is important. The experiment with the screw driven only halfway in and then broken off with a hammer is just not representative of the forces we are looking at.

So here is the experiment (moderators, if I am straying to far off the topic of trains, just let me know):

I attached an 8 foot long 2x4 to my 4x6 post, first with nails, then with screws. The 4x6 post is solidly attached at top and bottom, so it doesn't move. Once the 2x4 was attached, I put 5 - five pound boxes of screws in a bucket, then placed the bucket on the 2x4 near the post and slowly moved it away.

Here are the nails and the screws. The screws are 3" gray coated screws. The nails are about 3/4" longer and bigger in diameter.

   

Here is the setup. The 2x4 is suspended in the air, held up by only the nails or screws at the post. The nails/screws were placed horizontally along the length of the 2x4 and were spaced 3 inches apart.

   

Then I took the bucket with 25 pounds in it, and slowly slid it down the 2x4 away from the post. With the nails and the screws, the 2x4 began deflecting at around 18", and the deflection increased as I moved the bucket away from the fulcrum point. Now, with the nails, at 5 feet from the fulcrum, the bucket touched the ground as shown in the photo:

   

At 5 feet, the screws were still holding the weight up. Not as much deflection as the nails. The photo shows the bucket above the ground - this is at the same distance as where the nails let the bucket touch. I then moved the bucket even further down. The bucket didn't touch the ground until I got to 6.5 feet.

   

Between testing the nails and screws, I had to remove the board from the post. With the nails, a little tug and they pulled right out of the post. But with the screws, they actually pulled through the 2x4, heads and all, and stayed in the post. They were bent, so I couldn't remove them with the screwgun, so I whacked them with the hammer and they broke off.

I repeated the experiment just to make sure, and had the same result again. And, what if I had used screws that were equivalent in diameter to the nails? Maybe I'll try some more of the experiments I thought of. Also, anyone want me to try anything in particular?

Thoughts anyone?

[Gary S]

Nails and screws are relatively easy to pull once you get a grip on them, with nails more-or-less being removed from the hole created by their installation and screws removing the material immediately around them. If you're installing a ringed flooring nail with a hammer, and for some reason (hit a water pipe ) have to remove the partially-driven nail, chances are it will either also remove the wood around the rings, much as a screw would, or the head will break off.

I agreethat the ring shanked nails are very good. Perhaps they would provide the highest strength factor. As for pulling the screws out, I'll have to check that. Not sure it would be quite so easy!

Most building codes have regulations governing lumber specifications (permitted spans, loads, live load limits, etc.) and also nailing "schedules" which specify how many of what type, size, and length of fastener are to be used for each particular application.

Would the codes contain info on using screws for framing? Probably not. Would that be just because it is not a standard method, so nobody ever did any tests?

A lot also depends on the metallurgical properties of the fastener, especially for screws - I've bought screws that were of such poor quality (one big guess where they were made) that the heads snapped off as the screw was being driven, or the material was so soft that the socket was mangled by the driver bit, even though the fit between the two was excellent. I've also had many instances where the screw will bend while being driven.

Or is the variable quality of the screws that is at issue with the building codes?

[Gary S]

Nope! Just move the roof!

Good one!

[Gary S]

If you're installing a ringed flooring nail with a hammer, and for some reason (hit a water pipe ) have to remove the partially-driven nail

Wayne, I take it that you are speaking from experience on this one?

[Gary S]

I know I am getting way into this, but you guys have me thinking about the structural integrity of my building.

Found a study on connecting the rafter/ceiling joists/roof to the top plate which is typically toe-nailed and an accepted practice in building codes:

<!-- m --><a class="postlink" href="http://goliath.ecnext.com/coms2/gi_0199-324627/Testing-and-analysis-of-the.html">http://goliath.ecnext.com/coms2/gi_0199 ... f-the.html</a><!-- m -->

Excerpt: "According to building codes, toenailed connections between lumber members are to be fabricated by either three 8d or two 16d and box or common nails. The connectors included 8d (0.113 in.) and 16d box (0.135 in.) nails, 16d common (0.162 in.) nails, and 2.5-inch drywall screws. All specimens prepared for testing were at controlled 12 percent moisture content"

So they also tested drywall screws...

Excerpt: ."According to the IBC code, all residential buildings in the United States are required to meet 85-mph designed wind loads; most of the states, in fact, require the buildings meet designed wind loads of 90 mph. Our test result shows that only toe-screwed connections, rather than toe-nailed, can meet the 90-mph wind uplift load."

and

"Our results have shown that when the toe-nailed connection is replaced by fasteners such as screws or metal straps, the connection capacity of all species would increase significantly."

So the screws made a stronger toe-nailed joint than the nails.

And from the data table, using SPF lumber, the 16d common nail connection failed on average at 518 pounds which was the strongest of any type of nail tested. But the 2.5 inch drywall screw connection failed at 816 pounds, significantly higher than any of the nails.

Anyway, I am still going to replace the little brittle drywall screws I used on the joist hangers with nails. I'm glad you guys brought up the discussion! My train building will be all the better for it.

Thanks!
Gary

[yellowlynn]

I was on a mission trip to Jackson, Ohio to build a church. We used 5 1/2 TON of nails. The reason? state codes required 70 nails, repeat, 70 nails at all truss joints with 1/2" plywood gussets. Pound 35 in from one side, turn it over, crimp the nails and put in 35 from the other side. Then turn it over and crimp those nails. It sure splintered the plywood, but the state inspector said those were the best trusses he'd seen (????????) . I think the trusses were about a 40 or 50" span. We had no nail guns, all by hand. Talk about sore arms!!!!

Lynn

[doctorwayne]

I was on a mission trip to Jackson, Ohio to build a church. We used 5 1/2 TON of nails. The reason? state codes required 70 nails, repeat, 70 nails at all truss joints with 1/2" plywood gussets. Pound 35 in from one side, turn it over, crimp the nails and put in 35 from the other side. Then turn it over and crimp those nails. It sure splintered the plywood, but the state inspector said those were the best trusses he'd seen (????????) . I think the trusses were about a 40 or 50" span. We had no nail guns, all by hand. Talk about sore arms!!!!

Lynn

Wow! You'd think that with that many nails through it, there'd be little wood left, leaving a weak spot in the truss.

When I built my house, I discovered that the architect who did the blueprint probably had little or no training in engineering, as he had a pair of 2"x10" joists spanning the kitchen ceiling at the point where the upstairs outside wall needed to be located. In addition to supporting that wall, those two joists were to have the upstairs floor joists hung from them (running at right angles), in addition to supporting the load of the upstairs roof. Equally ridiculous was the fact that the joists were to be 24' long! Surprisingly, the local building department approved the plans. I caught the oversight before construction began and went to the lumberyard that was supplying the materials, mainly to see if their truss department could design a "wall" truss, which I estimated would need to be a full 8' high, that would do the job. Looking at the blueprint, the engineer agreed that it would be feasible, but that it wouldn't need to be so deep.
Once I had the ground floor framed, I called them to come down to take measurements for the truss, which they did. I was surprised (as were they, I'd guess) that the required truss would be comprised of three identical trusses, each 8' high and 24' long and built-up from 2"x6"s, shipped as three assembled units, and to be installed separately, then joined together. Set out in the accompanying paperwork were the specs: two rows of 5 1/2" spiral nails, spaced 6" apart, and applied from both sides (staggered), with the ends clinched-over. This was to be done on all members - top and bottom chords and all crossmembers. I managed to get all three trusses in place singlehandedly, but either standing on a ladder or dangling from the truss itself, it was tough work hammering all those nails in place, especially since I'm not particularly comfortable even standing on a chair to change a light bulb.

Gary, I think that part of the reason that screws aren't normally considered for this type of construction is the cost and the installation time. Most home builders aren't especially concerned with quality (despite their ads to the contrary) but they are concerned with getting done as cheaply as possible and on to the next project. Luckily for them, most homeowners know little of proper construction techniques (and many building inspectors can't be bothered to check thoroughly, either), so everything that's built gets bought regardless of whether it's well-built or not.
As for the screws, good-quality ones are still available (you get what you pay for, though). I also discovered that ringed flooring nails will, over time, work loose enough that their heads will protrude - I'm guessing that this is at least partially due to the wood drying out over time, plus the flexing of the floor itself. I discovered this when we replaced some wall-to-wall carpet with hardwood - luckily, I reset all of the displaced nails, then doubled-up on them with flooring screws before the hardwood was installed.

Wayne

[Gary S]

YellowLynn, 75 nails at each joint sounds outrageous! And 5 1/2 tons of nails is outasight! Wow.

Geez, Wayne, you manhandled the 24 foot long trusses by yourself? Yikes! :o When you built your house, did you already have your layout in mind and fashion the basement accordingly? Or did your interest in trains come later?

[Gary S]

In my internet searches on screws versus nails, most of what I found was anecdotal evidence that house framing is stronger with nails. This was from carpentry or builder forum discussions. Man, those guys get downright irate when someone asks if screws may be better than nails - "By God, I have been using nails for 20 years and the inspector passes it, therefore nails must be better than screws" and "What kind of ignoramous would use screws when everyone knows nails are better?"

This one guy had asked if there are any scientific tests which determined if nails were indeed better than screws. They went off on him big. Called him all kinds of names, etc. "Hey doofus, why do you need a scientific test? Every house I built was with nails so nails must be better."

Of course, the only evidence against the screws was the "drive it half way in and whack it with a hammer" test. I just don't see that as being a realistic test of the loads that a screw would be subjected to. And the scientific toenail test I mentioned above certainly suggests that screws may be better. And my little experiment did also. Anyway, I feel confident in the screws. Now... back to the building! The rain has moved out, it is clear and sunny, so time to get some work done!!!

See y'all later!
Gary

[tetters]

In my internet searches on screws versus nails, most of what I found was anecdotal evidence that house framing is stronger with nails. This was from carpentry or builder forum discussions. Man, those guys get downright irate when someone asks if screws may be better than nails - "By God, I have been using nails for 20 years and the inspector passes it, therefore nails must be better than screws" and "What kind of ignoramous would use screws when everyone knows nails are better?"

This one guy had asked if there are any scientific tests which determined if nails were indeed better than screws. They went off on him big. Called him all kinds of names, etc. "Hey doofus, why do you need a scientific test? Every house I built was with nails so nails must be better."

Of course, the only evidence against the screws was the "drive it half way in and whack it with a hammer" test. I just don't see that as being a realistic test of the loads that a screw would be subjected to. And the scientific toenail test I mentioned above certainly suggests that screws may be better. And my little experiment did also. Anyway, I feel confident in the screws. Now... back to the building! The rain has moved out, it is clear and sunny, so time to get some work done!!!

See y'all later!
Gary

LOL!!! That post made me laugh. Just because of the comments you uncovered, which only proves my point earlier about discussions similar to this turning into a slug fest. I agree, the drive it in half way and whack it with a hammer is not an accurate test of strength. All the demonstrator has done is create a fulcrum or pivot for the hammer gain leverage against each type of fastner.

[doctorwayne]

Hey, Gary, the old hands always know the best way is the only way - since they know only one way,it must be the best one!

When you built your house, did you already have your layout in mind and fashion the basement accordingly? Or did your interest in trains come later?

The interest in trains has been with me at least back to when I was three years old. The real ones, steam at first, were right across the street from our front door.

When I designed the house, I had a train layout in mind, but not one in particular, which was probably a good thing, as I "lost" large parts of the layout room (which was supposed to be the entire basement - about 1200 sq. ft.) to "other uses". I'd prefer to have the layout in a separate building, as then I could have visitors whenever I wanted, since, as it stands now, the powers-that-be have nixed visits from all but long-standing personal acquaintances. In reality, a separate structure for the layout (even if we go ahead and build another house) is impractical, cost-wise, as it would require both heating and cooling, neither of which are needed in the basement.

I had a rough sketch (no dimensions other than the room size) of a trackplan, of which I managed to save only a few elements when the room size got "adjusted", so the current layout was built-to-fit, with the "trackplan" evolving as I worked my way around the room and through a pile of lumber. I know what I want to include if I ever get around to building the long-delayed second level, but if I ever build a totally new layout, it will be an example of "less is more", with less track (figuratively speaking) but longer runs between towns, and fewer towns.

Wayne

[Gary S]

LOL!!! That post made me laugh. Just because of the comments you uncovered, which only proves my point earlier about discussions similar to this turning into a slug fest.

The threads were pretty interesting, funny to see the bickering. One old hand had written something like "Look, we all know that you're going to use the screws anyway, regardless of what we tell you, so why did you even ask?"

Another guy had asked about using screws to build a deck and one answer was "Go ahead and use screws, just don't ever invite me over to stand on it."