Rim Joist Size, Hangers and 16oc, or not

bthomas67wagon

I am going to build my own house and ALWAYS over do things. I figure if you are going to do it, DO IT RIGHT (and over do it!!)

The house will be 30x40, basement and "3 stories". (Basically the 3rd floor will be a 12/12 slope gable roof with 2 kids bedrooms)

I'm going over board with 2x6 exterior walls (2x4 interior) and 2x12 rim joists and floor joists.

1. What do you think about using Pressure Treated Rim Joist?
2. Would you use Joist Hangers or do you think the extra strength and cost is not worth it?
3. I am going to stick with 16oc for the Floor Joists and was wondering if that is way OVERKILL?

Thanks
Brent

Gary in WA

Welcome to the forum!

1. P.t. wood will shrink way more than solid wood at the rim. Use engineered wood for no shrinkage there; http://www.buildingscience.com/docum...d-but-strange/ Waterproof seal the sodil wood rim as even p.t. wood will absorb water, especially the mud sill (use a sill sealer under that); http://www.greenbuildingadvisor.com/...-building-code

2, As compared to a 2x2 ledger? Use the hangers with more uplift and load shear. Be careful when using a built-up flush beam; pp.51: http://books.google.com/books?id=iwS...rafter&f=false

3. Depends on the span, load, grade and species of wood used, if solid lumber; http://publicecodes.citation.com/ico...002_par017.htm

Gary

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mrgins

If I was building my own house, I'd use engineered floor joists and therefore, an engineered rim joist. You are certainly not overdoing things here!

bthomas67wagon

#1. I like the idea of using SPF and not engineered wood (for a couple reasons), but it sounds like using NON-Pressure treated wood for the rim joist is the answer. (and yes, of course I'd be using PT for the mud sill and a sill sealer).

#2. I'm still talking about floor joists and not roof trusses. Actually no hangers needed for the 1st floor as the joists would be either 10 inches on the mud sill or over lapped on the center concrete basement divider wall, but I guess on the 2nd and 3rd floor would be more of where I was concerned with hangers vs being nailed into the rim joists?

#3. Because the span will only be 15 feet, 2x12's would seem a little over board compared to 2x10's, but ???

After I typed 16oc I guess I should have corrected that because I was going to see what you all thought about 16oc vs 24oc on the 2x6 wall framing, but didn't want to confuse things... (sorrt about that)

I wish I had my diagrams to better explain what I am doing, but forgot them today.

-Brent

rditz

I built an addition and used engineered floor joists.. there are a number of advantages over solid lumber:

1) they are easier to work with, much lighter
2) they are perfectly straight
3) they have knockouts for wiring and such
4) they have nice wide surfaces to attach flooring to.

my span was 17' and 2x12 would have been mandatory for that span, so you are definitely not overkill with a 15' span.

i also found that the cost would have been close regardless of which way I went, so it was worth it to go engineered.

rod

Gary in WA

I would contact your local Building Department for some answers and direction.... Are you designing for 90mph winds or? http://www.awc.org/pdf/WFCM_90-B-Guide.pdf Are you in a seismic zone or on the Coast? Snow load for your area? Soil test for foundation size, etc.? Start with them and then go for the smaller things......

Gary

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Joe Carola

1. What do you think about using Pressure Treated Rim Joist?

Don't use it at all. It's a waste of money and it shrinks. There's no reason at all to use it. It' not an exposed deck.


2. Would you use Joist Hangers or do you think the extra strength and cost is not worth it?

No, not at all. No reason too unless you have a flush girder.

3. I am going to stick with 16oc for the Floor Joists and was wondering if that is way OVERKILL?

It's not overkill, that's standard every day framing. Some people use 24" centers.

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Joe Carola