Ridgebeam / rafter connex in Cathdrl Clg
Iltud
| Posted in Construction Techniques on
Hi all –
Looking for some suggestions for a particular wood framing connection.
The scenario: A 6×16 ridgebeam / 3×6 rafter connection as part of an exposed cathedral ceiling. (5/12 slope roof, 2′ OC rafters, ridgebeam and rafters are structural). At this connection, what are my options for connectors / connection techniques if the rafters are to meet the face of the ridgbeam, i.e. not rest atop the ridgebeam at all? I’d like it to be a ‘concealed’ connection, no metal connectors visible. I’d also like to avoid doing any complicated wood joinery on the ridgebeam. Toe nailing work here?
Ideas?
Thanks in advance –
Joe
Replies
Have you checked the simpson cat.?
They have concealed connectors
http://www.strongtie.com/products/connectors/CJT_APG.html
Keep looking thru their line of timber hangers they have some black iron hangers that may add a look you like
Good luck sounds like a cool project
Steve
NAIL IT !!!
Joe,
Who says that you even need a connection? Is this something you designed yourself? Toenailing works where I'm from but may not where you’re from.
You could drill a pilot hole for a toe nail so it has less tendency to split. After you have both sides in you could put a light strap across both the rafters and ridge.
Just a sugestion.
Many years ago, when faced with the same problem, I went to a local welding shop where they often did repairs on stainless steel tank trucks. I asked them to cut me X# pieces of stainless of the same gauge they used for the tanks. The pieces were sized so that they could be used as straps, about a half inch narrower than the 4X8 rafters, from about one foot down each rafter over the ridge and down the opposing rafter. I stacked up a few pieces at at time and drilled holes in them to accomodate #10 stainless screws. When it came time to install them, I screwed one side down and then used my framing hammer to bend the strap over the ridge, tin smith style.
Why stainless steel?
<<Why stainless steel?>>
The ceiling material was/is prepainted homesote, inch and a half thick. It was applied as roof sheathing with that interior finish. My concern was that any condensation that found its way to the strapping would cause oxidation which would stain the painted ceiling. Considering that the ceiling peak is about twenty-two feet above the floor, touch ups could be a major project.
If stainless hadn't been readily available, I'd have gone with galvanized straps and screws but, in this case, I was able to get the better material.
Assuming that your rafters are going to meet your ridge at the top of the beam, you will have a lot of beam face below the bottom edge of the plumb cut of the rafters. Why not run a ledger board made from the same species of wood on this beam face that the rafter could rest on? You would still need to toe nail the rafters to the ridge for pullout, but this way the weight of the upper rafter end would be supported by the ledger.
If you want to get neet about it, size the ledger so that it is flush with the bottom of the ridge beam and has a bevel cut on its' top edge matching the rafter slope. This system has the added benefit of giving you something to set the top of the rafters on as you are installing them, and automatically sets them all in exactly the same plane.
Thanks much to all for the feedback. I took a look at Simpson ties, found a concealed-type connection but not for sloping members - so I think for simplicity pre-drilled toe-nailing and top straps is going to be my route then.
Thanks again -
Joe
Joe, A shouldered tenon would be quick and easy for this. With a jig and a router both mortise and tenon could be done in a minute. Mortise could be freehanded since the shoulder covers. Add a lag screw through the top to pull tight.Toenails in a timber frame make me queasy.KK
Well, you don't want exposed fasteners and you don't want fancy joinery. So that leaves two options that are immediately apparent to me.
First, you can simply strap across the top as others have mentioned.
If this was being done in a timberframe shop, a likely scenario would be to drill through the tops of the rafters and through the ridge (parallel with the floor) and through bolt the two opposing rafters together. We would probably router 1/2"-1" deep pockets into the ridge beam, both for positive placement and to make it visually more appealing, since you are going to see shrinkage in the ridge beam and also probably in the bottom of your rafter cut with members of that size.
"First, you can simply strap across the top as others have mentioned"
If the ridge beam is loadbearing and no provision has been made to resist outward pressure at the exterior walls, the force acting where the beam and joists meet is entirely vertical ( see thread 82264, "Drilling thru a ridge beam). Strapping across the top of the beam is not going to address this.
Sit the rafters on top of the beam and use a 2x rafter tie to make a small flat at the peak. This flat will make it easier to hang ceiling fans.
"If you can dodge a wrench you can dodge a ball." Patches O'Hoolihan
yeah, second thoughts now have me leaning towards the shallow mortise / shoulder tenon that KK is describing. "In minutes" is the part that I will have to add the DIY newbie factor of x20 to, but the more I think about it the more I like that this connection allows for some movement / shrinkage in the wood without affecting the look of the joint. And of course that there is a gravity connection to the ridgebeam rather than pure fastener.Thanks -
I've used a shallow sliding dovetail joint for that application. Simple and fast with a large router and jig.
Blew the mind of the inspector (looking for a fastener). She walked away shaking her head, and gave approval. And pretty much left me alone after that.PAHS Designer/Builder- Bury it!
Yeah, dovetails work great in certain woods, especially hardwood. They are pretty much a no no in fir though, since it is so brittle across the grain that way.
You're right. I never see fir. Red oak's the next p&b project. Nice to use what grows here. Hardwoods.PAHS Designer/Builder- Bury it!
sounds cool, Gotta picture by any chance?
No I don't have any pictures, I framed one last winter with a cross vaulted ceiling that had the flat at the peak. Very nice looking in the end.
It also hides the beam so that you don't have to skin it with any finished hardwood or drywall.
"If you can dodge a wrench you can dodge a ball." Patches O'Hoolihan