Cross Bracing

[urbanfixie]

Hello everyone. I am new to the forum but I have wanted a TT for years and I have finally started building one.

My question is, what is the best method for attaching the roof cross bracing to the side walls? Should I be concerned about screwing through the side walls into the ends of the ply because of splitting?

I bought 3/4" maple plywood for my sidewalls and 3/4" birch plywood for the cross bracing. I had planned on laminating 2 pieces together to make 1 1/2" x 2" braces attaching the two by pre-drilling pilot holes and screwing through the sidewalls into the end of the braces. Thanks!

[Moho]

I did pocket screws and Titebond II glue. Screwing into the endgrain like you suggested doesn't create a very structurally sound joint in my opinion. Screws tend to pull out when used in the endgrain

[bobhenry]

I found this early on.........

Notice the little close up at the top.

Lead me to do this .....





and on the next trailer...






When attaching the spar to the sidewall I glued heavily and predrilled and installed one 2 1/2" construction thru the sud side panel and upward across the grain at slightly less than a 45 degree angle to allow the screw to bite across grain ( kinda sorta )

I cut all the spars from #1 southern yellow pine ( most 2x10 and 2x12 lumber are grade #1SYP ) This species is more dense than SPF and less likely to split and in all counts about 1/2 again as strong. As a note cut 3 or 4 extra if ripping them, you will find a couple will grain release and go a bit crazy either twisting or bowing. I simply set them aside to cut into smaller parts when building my cabinets.

[aggie79]

I used 1x2 poplar for spars. They were pocket-screwed to the sidewalls as Moho did and I used a deck screw in each as Bob did. Using both methods was overkill. The real strength comes from gluing the roof plywood to the spars and sidewall edges to form an assembly.

[urbanfixie]

Thank you for your quick responses!

I hadn't thought of either option. Today I located a local company to cut all my pieces with a CNC machine. I think I am going to have them notch the sides 1/8" around the perimeter so the cross braces and 1/8" ply will rest on it and then pocket screw them.

I am sure this is overkill to but I can't think of any reason not to. Can you? Another advantage is I won't need trim around the sides.

[OuttaHand]

You can check my build log here:
http://webpages.charter.net/outtahand/littletow/index.htm

I've got some pretty good pics of my roof spars going in.
I used a Kreg Pocket Hole Jig to attach them. It worked absolutely great!

The only thing I might do differently next time is to notch the side wall and rabbet the roof spar first. That way I could be assured that they would end up flush with the top of the side wall.. Doing it the way I did, some of the spars were uneven with the side wall by 1/8 to 3/16" or so. That made life a little rough in some points.

I also PL Premium on almost all my joints. I wanted the extra security of a really good adhesive to help the screws.