Thread: Rafter to beam connection at an angle - approx 100 degrees.

Billbee,
It's actually rafters I'm hanging this time so the angle bracket will look terrible.

thebuildingsurv,
Can't screw in from the beam into the end grains 'cause there is no access. The beam opposite the house fascia runs along the property perimeter and in some parts along the neighbouring property's garage.

DvdHntr,
If bugle screwing through the end grains is feasable, isn't skew bugle screwing through the side grains also feasable?
And what gauge would be appropriate for F5 Seasoned TP rafters 190 x 45?

And what of this as a matter of interest.....
How about when I see sheeted pitched (gable or hip) verandahs and they've used - no ledger to support the rafter and no multi or triple grip to fasten it.
How do they do it? Are they simply skewing a couple nails in or using some other method we don't know about. And I don't mean in backyards either. I'm talking about in parks, council / public areas. I can't remember seeing a joist hanger or grip of some sort used anywhere.

Cheers boys, keep it coming,
Dr - 307.

The uplift capacity required for the joint is determined by the design wind gust speed for your area.
i.e. for a N2 site [in melb] the uplift pressure per joint for seasoned pine is approx. 0.74 kPa for a sheet roof.
Multiply the roof area held by the connection by 0.74
i.e rafter span 2.4m at 900 spacings = 1.2 x .9 x .74.
Equals 0.799 uplift capacity required.
2/75mm skew nails = 0.66 kN so doesn't meet requirements.
A single framing anchor with 4/2.8 diam nails each side = 3.5 kN therefore OK
The next question is what if you use 4 skew nails ?
And the answer is probably but it's not covered by the framing code that I know of.
At the end of the day if your rafter spans exceed say 2.1 met then I would go for a 'made up' metal side bracket to suit the angle with at least 4 /40mm*2.8 diam to each leg plus skew nailing to initially tie the rafter to the fascia beam.

I've used custom made metal brackets (6mm thick plate) sitting on top of the hip/valley and extending down onto the tops of the rafters with whopping big coach screws in them. These prevent uplift. The rafter can't drop down because it's supported at its lower end on a pole plate and would need to pivot from the birdsmouth on the pole plate to fall down. As it pivots it effectively grows in length, thus preventing it from falling down. A few 3" nails hold it in place until the steel plate is fixed.

Mick

Originally Posted by Dr - 307

DvdHntr,
If bugle screwing through the end grains is feasable, isn't skew bugle screwing through the side grains also feasable?
And what gauge would be appropriate for F5 Seasoned TP rafters 190 x 45?

Yes it is but how are you going to screw into a side grain? Are you referring to skew screwing? I hope not.

The gauge issue is that from end and edge grains there are limits that apply that are related to gauge (diameter).

Have you thought of using a ply backing or attaching a second plate to correct the angle.

The beam opposite the house fascia runs along the property perimeter and in some parts along the neighbouring property's garage.

Now i know u dont have a permit

DvdHntr,

I was referring to 'skew' screwing. I take it that that's a big no no! Or not?
Can you better explain the limits associated with gauge and end / side grains.
No, I haven't thought about correcting the back angle as yet but that's a thought although not to keen on that.

What about on the issue of LVL. Can you notch LVL out. Just a bit so that it sits in and on the ledger. I was looking at my rough drawing and at the wider end of the roof the rafter span will be 5500.

Here's the area in question.

Attachment 67273 Attachment 67274

Firstly, that roof covering including the window and waist high brick rendered wall is coming down. Looks like it goes into the house roof but I had a very good look and it's attached to the fascia and very cleverly filled and painted to look otherwise.
The patio area will remain. The deck will start and run over the patio area (2 x 2m) and then come out left as we view past the ferns to the neighbouring garage wall. From there it continues along the wall for about 5m.
The narrow far side span of the roof is 3m.
The wide span from where the shot was taken is 6m.
Total length approx 8m.

Yeah I know, 10 degrees my foot. But my concern was fastening the rafters regardless of whether the angle is 10, 15 or 20 degrees.

I'm now thinking of using LVL for the rafters (at least for the extra long spans) but don't know how they take to notching. I've used hyJoist before to build a single span 4500 x 16000 messanine storage floor but obviously this stuff is different.

What do you think.........guys???

Doc.

Originally Posted by thebuildingsurv

Now i know u dont have a permit

Nothing a $350 dispensation application wouldn't fix. Asked my brother-in-law if he wanted plans but said........anyway you know what he said.

Check out the pics and see what you think.

Ta,
Doc.

Use the wall plate and the ledger. I would still recommend multigrips to each. I know some people get away with it but the brackets cost very little and the extra insurance is worth it.

If the span is getting up to 6m then the LVL may be an option, I would check with the HySpan technical brochures as to whether there is any issue with notching in an exterior environment.

If you are going to skew just skew nail. Skew screwing is possible but you wouldn't want to. Have you thought of running the joists the other way? Have the spans as 4m each side of a centre beam and have end beams. That way the joist spans are shorter and the beams can be larger but less of them. You could use a hiload truss bracket (3 or 4 bolts) directly into the wall and pack out some timber/ply and bolt through the flange for tie down. 3 connections at the wall is easier than 9.

DvdHntr,

I've been thinking about using LVL all weekend or like I said at least for the longer members. I still want the rafters to run conventionally.
I'll construct it with footings along the fence line (just to keep off the boundary) and I'll go into the ground as opposed to just using post supports on concrete. I'm going to sit the opposing beam on the inside of the posts so we are looking at a straight even surface for a ledger to run along and then use multigrips for the fastening (for the extra insurance) of the rafters to the beam

I'll ring hySpan and speak to them about notching and spans. For the perimeter I'll use Design-Pine as well as the posts (115 x 115 post size only). This will give me my smooth look and more strength over the F5 TP Dry.
Design-pine I've been told is rated as F7.

Now, something slightly related (although I feel it will eventually become my best friend) but more to do with tools.
What is the brand of nail gun suitable for j/hangers and the like where it shows the tip of the nail so you can direct the nail exactly through the right hole in the bracket rather than slam straight through the metal and risk tearing it?

Cheers,
A very sorry and tired Dr - 307 after 2 days in Mt. Martha. Sunnies are my best friend at the moment.

Originally Posted by Dr - 307

................What is the brand of nail gun suitable for j/hangers and the like where it shows the tip of the nail so you can direct the nail exactly through the right hole in the bracket rather than slam straight through the metal and risk tearing it?.........

Bostitch makes one, (coil nailer) but I'm not sure about the model number. I don't know if anyone else makes one.

Mick

As a former engineer of Multinail, I know they do not want you to use any nail gun for the very reason you stated.

DvdHntr,
Not even the gun with the protruding nail head?
If you're nailing into the hole of the hanger where is the problem?

journeyman Mick,
Bostitch? Thanks for the recommendation. I'll look them up. I might even do a tour of the Tool Pages in the forum.

Dr - 307.

I don't know much about the nail gun but I know that many nail guns would damage the plate as they are only thin gauge.

OK, thanks DvdHntr. I'll keep it in mind. I know I was reading on the forum about a nail gun that did what I'm wanting. There was much debate. I'll find the thread and have another read.
Cheers,
Doc.