Notching High Span Floor Joists

[zacnelson]

Hello, I hope the attached picture will explain things properly. My new extension plans specify high span floor joists, 250 X 38, attached to a 4 X 2 plate on top of double brick base walls. I need to get the finished floor level to match the floor level on the existing house, which is 45 years old and has bearers and joists. I need to keep the brick courses at the same heights as the courses on the existing house, which will have an impact on where the joists will sit. Therefore, it may be difficult to get the floor levels to match, without perhaps notching the ends of the joists (as little as possible of course). My question is, will this be acceptable? Will it pass a sub-floor inspection?

Thanks

[Outbackrr]

Safest option is to email manufacturer with your question, assuming you get positive response (don't see why you wouldn't) you will then have evidence to present at inspection.

If they're CHH Hyspan - http://www.chhfuturebuild.com.au/ind...ge/Contact+EWP

[Honorary Bloke]

Check with the manufacturer, but . . .

In general, high-span type joists are NOT allowed to be notched, as the cross pieces of the I-beam type construction provide the majority of the strength. A better solution may be to install joist hangers if possible, at a point low enough to match the existing flooring.

[Skew ChiDAMN!!]

I wouldn't. Not because of any tech specs, mind... it's solely because it rings that little bell in my head.

Instead, I'd be inclined to make the piers a course or two lower and run a ledger of suitable height across them. If needed, that could be notched out instead of the joists.

[Ivan in Oz]

it's solely because it rings that little bell in my head.

You mean like the Old gut feeling????

Funny place for your Head

I'm finding that 'the' "Gut Feeling" gets more accurate with Maturity
.....I mean AGE

[les88]

Your drawing shows that the joists are clear of the brickwork, I would pack under them with fibro.
les

[Honorary Bloke]

Your drawing shows that the joists are clear of the brickwork, I would pack under them with fibro.
les

Doesn't seem that way to my eyes, but maybe I'm wrong. The drawing looks like a regular joist, but the OP said he is using high-span type joists.

In any event, to put it another way, notching high-span joists would be against Code in the States and would not pass. Notching a regular joist would be OK if not more than 1/3 its total width.

[zacnelson]

Thanks for all the suggestions. I probably confused things a little when I said high span. I don't mean modern manufactured joists like `hyspan' or `hybeam'. I wouldn't dream of notching a hybeam joist, the structural integrity of a hybeam joist would be compromised if the bottom was notched and the webbing was directly attached.
My plans specify `250 x 38 F7 unseasoned softwood floor joists @ 450ctrs, 3900 max single span'. That is why I considered notching, I wouldn't notch a posi-strut or a hybeam joist.
What I meant by high span is that the sub-floor is designed with joists that span further than your traditional bearers and joist set-up with 4 x 2 joists.
I hope that clarifies things a little!

[Outbackrr]

AS1684 allows D/4 (25%) max. notching at supports = maximum 62mm notch in your 250 joists.

[zacnelson]

Excellent, that's great to hear, I will now know precisely how much room there is to move.

Thanks again!

[SilentButDeadly]

Zac
I'm with Skew in that I'd consider notching the brick work rather than notching the timber as doing the latter as this essentially reduces the load strength of the bearer over much of its length.

Personally, I'd skip the 4x2 totally and go with a galvanised steel bracket bolted to the brick work. Adjust the bearer to the required height using Villaboard packing and the bolt the bearer up to the bracket....and I'd think seriously about using F17 OB hardwood instead of softwood for the bearer too.

[DvdHntr]

If your bearers are not short spans with intense loads on them then shear will not be a problem. But in saying that, because you are using I joists it will become a problem if you notch because of the limited depth of the flange. The web of the joist will be inclined to buckle. If you have to notch I would notch the ledger.

[zacnelson]

As mentioned in one of the other posts, I will not actually be using I joists, instead LVLs or hardwood, ie something solid without webbing.

[DvdHntr]

Then just notch the HySpan.