Using biscuits for exterior applications

[blueox]

It's my understanding the wooden biscuits are a type of wood that will swell with the moisture of the glue hence tightening the connection. This biscuit expands and if there is not enough material ( wood) you will see a bubble in the shape of a football..This can happen on a interior application if the material isn't thick enough.supposedly this architect used mitered corners with 3/4" beveled siding and got good results(Well the carpenters actually did the installation). Our siding is only 7/16" on the thick end could I cheat the plastic biscuit to the back side of the siding? Do you think this might just be asking for trouble?

[Mbeezo]

I have to ask why are you installing biscuits in siding like you are doing? I have yet to see a wood siding job where the joints have a bisucit installed in them. Is there not a way to just nail the stuff close to the ends of the boards like has been done for years and call it good?

[Bill Robinson]

I am confident the biscuits will telegraph, the joints will open, and you will get a do over.

This is good though since you will then have the real life experience that this is a flawed plan.

And the next time you will be able to tell the architect it does not work.

You are at risk of cupping, unequal wood movement from moisture content, and from building movement.

Sometimes you just have to take a stand rather than do something that is questionable.

I would consider a corner detail that does not require a mitered joint on exterior siding from today's wood.

[blueox]

That's pretty much what I was thinking. We're asking for trouble.I'm always up for a challenge but I think years of durability and performance are more important than this detail. Even if the majority of it stands what are you going to do with the few that don't. I value your opinions and experience

[Lavrans]

I have done mitered exterior corners. Not real common. Main problem is the Hemlock- it's a soft, rot-prone wood. Not a good choice for siding and won't be long lasting. Anyway, with that caveat out of the way, I would not use biscuits for that. Especially 7/16. But I think a headed nail will hold it well enough. Nail through both pieces; I nail about 3/4" up from the thickest part, then a pair of nails as close to the center as is practicable. I also use glue- both to help hold it together, and to seal the ends a bit when the miter does open up.

Hardest part really is cutting the miters right- I cut all the boards a little long so they aren't a perfectly tight fit to the corner- that helps to keep the miters closed.

[aerieandy]

I've used biscuits in exterior miters many times with lots of titebond III. At least in my climate they last, YMMV. That said I've only used them on 1 1/2" stock for trim, never for the siding. Done lots of mitered bevel siding, just no biscuits. Careful cuts, lots of PL (let it cure ugly, and razor the squeeze out the next day) and hand driven SS ring shanks are pretty bomber IF the material is good.

[Bill Robinson]

There is so much to consider:
climate
overhangs
exposure
material
framing

[ThingOfBeauty]

We've done a lot like Andy and Lav say, glue and nail, cut a bit long and use a saw with a hold-down clamp to help keep the skinny siding flat while you cut. It's not quick but it's quicker than biscuits and comes out fine.

I would not try to cut biscuits into skinny siding, lots to go wrong and no benefit I can think of.

[dixonpeer]

Blueox, I don't think it is a good idea to do mitered outside corners with bevel siding. Architects can draw anything they feel artistically inclined to on a piece of paper, but that doesn't mean it's doable or good practice. Anyway, if you do this job and miter the 1/2 x 6, you're going to be there a long time. And for sure you should flash behind each miter with Vicor or something like that; those miters are bound to "ship" some water.

[blueox]

Setting windows tommorrow .Unless he ties me down and beats me up we will not be mitering corners on 7/16" siding. I don't want to learn the hard way (anymore).I' ll show him this thread if need be thanx