trimmer joist

[ICE]

The span is 13'. The joists are 2x8 spaced 12". The hole that's framed is for the underfloor access. Would you require the trimmer joists to be doubled?

 

[steveray]

That has to be about max for a 2x8......common sense says double but I would have to check my span tables or prescriptive header stuff....

 

[DRP]

You know how to cut it fine

It looks like dougfir, it appears to be #2&btr, I see a couple that could be select struc, but the right hand support joist is a #2, look inside the hole. It just misses at a simple uniform load. Pencil it out finer and it might pass. It won't fail but it should be doubled.

I guess meeting existing was a big driver on joist size. At 2x10 they could have framed on 16's and the span could be 12'9" without a trimmer at the hole.

 

[Dennis]

I thought if a joist was cut they needed to be doubled on both sides-- is that not true or is that only if you cut 2 joist. IMO. a 2x8 13' is bouncy and if that is the max then cut and support as is shown is not sufficient. I have nothing to base it on other than what I have seen done.

 

[Gregg Harris]

The span is 13'. The joists are 2x8 spaced 12". The hole that's framed is for the underfloor access. Would you require the trimmer joists to be doubled?

R502.10 Framing Opening; Openings in floor framing shall be framed with a header and trimmer joists. When the header joist span does not exceed 4 feet the header joists may be a single member there same size as the floor joists. Single trimmer joists mar be used to carry a single header joist that is located within 3 feet of the trimmer joist bearing. When the header joist span exceeds 4 feet the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the floor framing into the header.

It appears to exceed the minimum opening and should be doubled.

 

[ICE]

Dennis,

The example I gave is pretty much a no-brainer yet the contractor complained about the correction to double the joists.

My usual reaction to a head-out in a floor is to double the joists in all cases.

There will be situations where it's not necessary and those are obvious.

 

[Rider Rick]

I would double.

Walk the joist.

It's a easy fix right now but later it won't be.

 

[globe trekker]

ICE,

Aren't the band joists overbored for the crawspace vents ( RE: Section R502.8.1 in the 2006 IRC)?

.

 

[Papio Bldg Dept]

ICE,Aren't the band joists overbored for the crawspace vents ( RE: Section R502.8.1 in the 2006 IRC)?

.

Aren't the floor joists bearing on the top plate? I'm not sure that 502.8 is applicable to rim joists, but am interested to hear what others have to say. This is common venting condition for similar crawl spaces in our neck of the woods (we don't really have woods here though).

 

[Dennis]

I shouldn't even be responding but I thought the band was not structural at all. In fact I saw a house done years ago where the builder didn't use a band at all.-- crappy construction, IMO but I thought it was compliant

 

[globe trekker]

Wouldn't the joist hangers make this band joist structural?

.

 

[Dennis]

Wouldn't the joist hangers make this band joist structural? .

Good point- I missed that. Generally they sit on a plate on top of the wall. These do not appear to do that.

 

[Dennis]

On this side of the photo there appears to be a plate though

 

[David Henderson]

Ice, another problem I see is the parallell rim joist need to be doubled or block at 16"oc

 

[ICE]

Ice, another problem I see is the parallell rim joist need to be doubled or block at 16"oc

While I think that's a good idea, we don't require a doubled rim or blocking unless it's over the crawl hole or particular shear walls.

About the only thing wrong with the rims in the picture is that the vent screens are already installed. The plywood must be installed before the screens and then the stucco.

 

[globe trekker]

Maybe ICE can clarify if the floor joists are setting on the plate (on

the closest side to the viewer) or by joist hangers. The nailing

pattern seems to suggest "resting on the plate". Good observation

Dennis!

.

 

[David Henderson]

look at 502.4

 

[pwood]

put a pier block under the headed out joist instead of doubling both joist. is there 18" under the floor joists?

 

[Dennis]

Tell me what good those vents are going to do with insulation between the joists

 

[Papio Bldg Dept]

put a pier block under the headed out joist instead of doubling both joist. is there 18" under the floor joists?

doesn't look like it...maybe it's a slither space?

 

[Papio Bldg Dept]

Tell me what good those vents are going to do with insulation between the joists

insulation? insulation! we don't need no stinkin insulation!

 

[Rio]

One side is sitting on a sill plate and is face nailed, you can see the nail heads on the band (rim) joist, the other side looks like it's tied into the existing house with some sort of ledger and joist hangers; where the joists are sitting on the sill the vents are right where the joist needs to be nailed to the rim so it's definitely screwed up one way or the other there.

An option to doubling the joists as the framing is done would be to put a pier and post near where it is headed off.

 

[ICE]

The joists are bearing on the mud sill. At the vents, there is a 16d at the top through what is left of the rim and toe nails at the sill. A foot from the rim is solid blocking. Plywood will be glued and screwed. You couldn't rotate those joists with a toe truck.

 

[Rio]

Tell me what good those vents are going to do with insulation between the joists

Hold the insulation back in those places enough to allow the air to flow into the crawl space. The band joist on a stem wall is a common place to put vents, at least in southern California.