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Small Cabin Forum / Cabin Construction / 3" Nails for Making Three 2x12s into Built Up Beams?
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cabinnewbie
Member
# Posted: 31 Jul 2022 10:53 - Edited by: cabinnewbie
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Hey all,
I'm working on building a 12x16 cabin, got my four holes dug for the concrete piers. Aiming to do the pour later this week once I got everything level and right. Pray that my piers end up exact same height.

I'm going to use anchor bolts with post bases and put beams right on top of the piers and then my joists on top of the beams.

I was planning to make beams out of three 2x12s nailed together. From what I read, seems like 3.5" nails are best to make the beam? Everything I see at Big Orange or Blue only seem to have 3" nails for a framing nailer.

They do have these 3.5" wire ones for a 28 degree nailer but I have access only to a milwaukee 30 degree nailer.

https://www.homedepot.com/p/DEWALT-3-1-2-in-x-0-131-Gauge-Wire-Collated-Galvanized-Fr aming-Nails-2-000-per-Box-DWS16D131G-FH/207070037

CAn I go with 3" ones or should I just hand hammer 3.5" ones?

gcrank1
Member
# Posted: 31 Jul 2022 12:57
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Dont you need more than 4 piers for a 12x16?

ICC
Member
# Posted: 31 Jul 2022 20:27
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Quoting: gcrank1
Dont you need more than 4 piers for a 12x16?


Same question came to me.

Is the mention of 4 piers a typo? If not how did you come to the idea that 4 would suffice?

ICC
Member
# Posted: 31 Jul 2022 20:30
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Three inch nails would not be a big problem. Four piers is a potential big issue for a few reasons.

cabinnewbie
Member
# Posted: 31 Jul 2022 21:50 - Edited by: cabinnewbie
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I talked with five carpenters/construction guys who've been around the land and two of them also live in the same region. They gave me the greenlight. I am cantilevering almost 2 feet so the span really is a little over 8' and 12'.

If I have beefy enough beams and joists then I thought it'd be fine. I'm going straight concrete pier to beam, no in-between posts.

spencerin
Member
# Posted: 31 Jul 2022 22:40
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We don't know how beefy your beams are, but even an 8' span is pushing it. There's no harm in playing it safe when a foundation is involved.

ICC
Member
# Posted: 31 Jul 2022 22:59 - Edited by: ICC
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A 12 x 16 would normally mean 16 feet long (the beams) and 12 feet wide (the joists). Is that interpretation correct? ...... Beam length 16 feet, joists at 12 feet OAL.

A joist span of 12 feet is easily attainable with readily available 2x materials. Joist cantilever over a beam end should be restricted to a maximum equivalent to no more than the height of the loist, unless engineering analysis is done. That is a 2x10 joist should be cantilevered no more than 10".

Beam end cantilevers follow the restrictions as joists or need an engineer. A 16 foot beam cannot be spliced if there are only two support points unless it is one piece like a manufactured glu-lam. Especially if you go ahead and cantilever the ends two feet.

The question about soil bearing remains unanswered.

Q's? What footing is planned under the sonotube piers? What size sonotube? What depth in ground? What type of soil; what PSF load bearing ability of the soil. Single story cabin? Snow loads?

Brettny
Member
# Posted: 1 Aug 2022 07:26
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Dont use nails. Use construction screws. Something with a large head would be better like GRK screws.

gcrank1
Member
# Posted: 1 Aug 2022 08:01
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Any idea what the 'screw schedule' would be for the 16' built up beams; and how many per beam?

Brettny
Member
# Posted: 1 Aug 2022 12:32
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A 16ft beam is prob going to bounce like crazy even with 2' cantilever. But I would put 2 rows every 16in.

cabinnewbie
Member
# Posted: 1 Aug 2022 22:07
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That's correct, joists running 12 ft, beams running long 16 ft

Using bigfoot 24" footings with 10" sonotubes. Soil is mostly clay, rocky. Didn't test the soil. With good pitch and metal roof wasn't expecting too much snow load.

Single story cabin, sed style roof.

Grizzlyman
Member
# Posted: 1 Aug 2022 23:12 - Edited by: Grizzlyman
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Just put in two more piers (one in the middle)and you’ll be fine. Easy.

ICC
Member
# Posted: 2 Aug 2022 09:18
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Quoting: cabinnewbie
Using bigfoot 24" footings with 10" sonotubes. Soil is mostly clay, rocky. Didn't test the soil. With good pitch and metal roof wasn't expecting too much snow load.


Good footings. Good tube size. Three per beam would be much better.

If the joists are resting on top of the beam all the fasteners in the beam do is hold the 3 layers together and keep the beam from twisting. They do not contribute to resisting any deflection (bending) strength. Nails are fine. IF you were hanging joists on the side of the beam that would be a totally different story.

cabinnewbie
Member
# Posted: 2 Aug 2022 12:58 - Edited by: cabinnewbie
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I could dig the two more holes, it took about two people digging 3-4 hrs per hole so I was hoping to avoid more if I had beefed up enough beams and joists....I guess would only add a few hundred more in supplies.

Luckily I guess it's raining a lot this week so I can't do much else but dig anyway too

frankpaige
Member
# Posted: 2 Aug 2022 14:12
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[b]cabinnewbie
I believe you will be glad you did add piers. No one likes digging holes. But no one like the bounce either. And is difficult to go back. Enjoy the process. Enjoy the cabin!

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