Oak frame plate join?

[pike]

I'm doing a "sun room" using 2x5 oak framing and full length glazed windows. What I'm not sure about is the best way to join two lengths of top plate.

The top plate is doubled up so it is 2x5 and another 2x5. I plan to stagger the join but what join to use? The posts are the same size so there isn't much width to play with.

If I do a half lap should each lap end before the edge of the supporting post?

That post is only 44mm thick.

If I was using blocking then the edges would be screwed or nailed down into that, so could I not just butt join them and fasten with screws/nails?

I would be happy to do m&t but I don't think it would work horizontally.

I'm just not sure the half laps being just 22mm thick is strong enough.

Cheers!

 

[hanser]

I know nothing about timber framing but my thoughts would be to to scarth joint the two pieces of the lower plate together and then M&T the post into it, the top half of the plate carrying over the lot.

I'm sure folks with more knowledge will be along soon..........

 

[pike]

I'm happy to m&t the post into the plates but I'd rather stick with a half lap than scarfing as I think that might be a bit beyond me!

There's not really the width for a tenon though in the above design, as I've stopped the half laps within the thickness of the post if you see what I mean.
The plates are only 44m so I don't know if it's ok to make the half laps longer and go beyond the post thickness.

As above it's strong but leaves no width for a tenon. If I do this:

I'd have room for a tenon but the strength is now on 22mm instead of 44mm.

 

[Dibs-h]

Can't you get 4"x5" timber instead?

I'd be wanting to stop the lap joints within the post - also how about having the "jointed" piece above the whole one? Or is it a case of deferring it to another post?

Dibs

 

[pike]

Hi Dibs,

I've already got the timber and it was a pack deal all at 44x121mm.

If I understand you correctly about having the jointed piece above the whole one. The whole top plate is about 5.5m long and is made up of 4 lengths, so there is a join on the top one too, but above a different post.

 

[MickCheese]

I'm no expert but I cannot see any problem with what you are proposing.

I would just locate it with a few dowels running through from the top piece to the bottom piece therefore locking all pieces together.

Mick

 

[bosshogg]

It's actually easier than you are anticipating _

You should certainly stagger the joints, and if you can cut the angles near enough the 44mm width of the posts all should be fine. This is the way they come out of the timber frame co's. if it's all right for them then they have had a an engineer advise them...bosshogg

Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?
T.S. Elliot :idea:

 

[GazPal]

It's actually easier than you are anticipating _

You should certainly stagger the joints, and if you can cut the angles near enough the 44mm width of the posts all should be fine. This is the way they come out of the timber frame co's. if it's all right for them then they have had a an engineer advise them...bosshogg

Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?
T.S. Elliot :idea:

Plus much less faff on than using halving joints.

 

[GazPal]

It's actually easier than you are anticipating _

You should certainly stagger the joints, and if you can cut the angles near enough the 44mm width of the posts all should be fine. This is the way they come out of the timber frame co's. if it's all right for them then they have had a an engineer advise them...bosshogg

Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?
T.S. Elliot :idea:

Plus much less faff on than using halving joints.

 

[sue denim]

If it were mine, which it isn't, I would place a short secondary sub plate below the horizontal and on top of the vertical. This could have a doucine type detail cut into the ends to make it look nice. This will spread the point load of the upright over a greater area. Then you don't have to worry if the horizontal isn't exactly over the upright and also supports any future movement.

If you get what I mean.

Sue

 

[pike]

Thanks all. Sue, unfortunately that won't really fit into the design I want, but I see what you mean.

I really like the look of bosshogs angled cut but I'm still not entirely sure how I join the plate together AND fix it on the post, when there's not really room for horizontal tenons/dowels between the plate join and one vertical up from the post.

Maybe I just need to use smaller tenons than the one third thickness 14mm ones I had in mind. I'm playing in sketchup now to see if there is in fact room for decent tenons in 44mmx121mm stock.

 

[bosshogg]

Sorry I did mean to add, two dovetail angle drilled holes from above and dowels glued in. Make sure the dowels are punched in, 1mm below surface to prevent any shrinkage displacement, fill resultant holes with silicone, trimmed flush.
Under normal covered timber frames i.e. where the header/studs would be hidden from view, the studs would be doubled, almost as per Sue's suggestion, but this is not essential if you cut and plane accurately

...bosshogg

P.S. you could plant on corbel type of decorative blocks?

I never teach my pupils. I only attempt to provide the conditions in which they can learn.
Albert Einstein (hammer)

 

[EddieJ]

Out of interest... Is this a paid job, or at your own property and you are having a go yourself?

I only ask, as there is far more than just this simple joint to be thinking about.

 

[pike]

Hi Eddie, it's just me part rebuilding/repairing an existing outbuilding which was rotten. Two walls are staying, I'm just replacing one half of it and putting a new roof on.

 

[tool613]

I'm doing a "sun room" using 2x5 oak framing and full length glazed windows. What I'm not sure about is the best way to join two lengths of top plate.

When the plate is a header you should run your spline/scarf up right. I use this type joint in that situation.

this gives full post support to both members. I used it on my shop here in canada.

jack

 

[pike]

Nice "shop" Jack! I had thought about doing a half lap upright. It looks and feels sound.

 

[tool613]

Nice "shop" Jack! I had thought about doing a half lap upright. It looks and feels sound.

In your case you have two plates, so its not the same.you would see a header beam or knee brace under that plate work to cut the span with two plates like that.What is the span post to post and how much roof is the plate/header supporting?And does the timber support a glass/glazed roof deck?


jack

 

[Dibs-h]

Do tell? :wink:

Cheers

Dibs

 

[tool613]

Do tell? :wink:

Cheers

Dibs

And there's the rub.

I do not know the Practice in England so i my be of no help,but the two plates you show have no load bearing strength as a header beam. you would have to have the rafters come down on the post and use purlins for the roof deck.

I will be following this one.

jack

 

[EddieJ]

Jack is very much on the ball.

There is far more going on than just the joint. If this were me, then my biggest concern wouldn't be the joint, it would be with the load bearing strength of a 44mm post.

Will a 44mm section post be enough for the load bearing? Are there fully framed glazing units going in that could possibly act as support, or is the glass just going to be fully floating and rebated into the 44mm post and plate above, which would leave even less support. What are the spans widths and height for each bay, and what's the roof covering.

Pike, post up a bit more info about the job, and we can see where it takes us.