# F or J Channel for slanted aluminum Soffits?



## joshhemming (May 8, 2015)

The only instructional video I've viewed said to snap a chalk line even with the bottom of the fascia and nail F channel into the side of the house. This will make the soffits at approximately 90 degrees from the fascia. That would look OK for a two story house. But since my house is a one story ranch type, I think having the soffits go straight back level from the bottom of the fascia wouldn't look right. The front and back of my house presently has plywood soffits that follow the slope of the roof. Most of the other houses in this area which have aluminum soffits also have them angled down, and that's how I'd like to install mine, too. 

It looks like using F channel nailed into the side of the house wouldn't work so good if the soffits are going to be angled downwards. Can I use J channel instead, nailed onto the bottom of the existing plywood soffits?


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## mako1 (Jan 7, 2014)

You can .The problem with the j is that it is wider which will allow your soffit to bounce around on a windy day.Nail the F up tight to the bottom of the rafter tails and you will still have a slope.You can even bend the flange on the f to match the slope of your rafter tails if you're that concerned about it.


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## joshhemming (May 8, 2015)

mako1 said:


> Nail the F up tight to the bottom of the rafter tails and you will still have a slope.


I was hoping to leave the existing plywood soffits in place....just put the new aluminum soffits over (under?) them. If I use F channel, I believe its nailing strip will prevent me from having the channel tight against the old soffits. J channel would eliminate that problem since its nailing strip would be flat against the bottom of the old soffits. The inner end of the soffits would slip into the J channel and the outer end would of course be nailed into the bottom of the existing 1 x 6 fascia board. At least, that's how I'm visualizing the process but I've never worked with aluminum before, only vinyl. 

It does get windy here in West Texas. Are you saying the channel itself of the J, which the soffit slides into, is wider than that of the F channel? Bouncing soffit doesn't sound very appetizing. Is there any practical way of narrowing the channel....perhaps with a spacer or shim?


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## joecaption (Nov 30, 2011)

Post a picture of what you have so we can make sure where not missing something.
You can use 1/2 J and there will not be any issues.
For an even better look you can go with vinyl cove molding like this.
http://www.certainteed.com/products...entry-trim/wall-and-soffit-transitions/345928
Is there any soffit venting if not there should be?
What's the plan to finish out the fachia and cover up the other end of the soffit.
The best way is to wrap it with coil stock.


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## mako1 (Jan 7, 2014)

joshhemming said:


> I was hoping to leave the existing plywood soffits in place....just put the new aluminum soffits over (under?) them. If I use F channel, I believe its nailing strip will prevent me from having the channel tight against the old soffits. J channel would eliminate that problem since its nailing strip would be flat against the bottom of the old soffits. The inner end of the soffits would slip into the J channel and the outer end would of course be nailed into the bottom of the existing 1 x 6 fascia board. At least, that's how I'm visualizing the process but I've never worked with aluminum before, only vinyl.
> 
> It does get windy here in West Texas. Are you saying the channel itself of the J, which the soffit slides into, is wider than that of the F channel? Bouncing soffit doesn't sound very appetizing. Is there any practical way of narrowing the channel....perhaps with a spacer or shim?


If your set on your way of thinking then why question it or what is your question? 
Yes the j channel is wider than the F which will leave some slop and allow the soffit to make some racket.
You can use 1/2" j without issues if they have it in your area.Either way the J and F flange is on a 90 degree bend so you will have the same issue if nailing it to the wall or rafter tails.It's kind of a mute point.


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## firehawkmph (Dec 12, 2009)

I've done a lot of soffits like you are talking about doing in aluminum. The J channel around here is 1/2", the soffit doesn't bounce around in it. It fits with no slop. You can tuck the J channel into the crease where the existing plywood hits the house and staple it in place with a 1/4" crown air stapler and galvanized staples. I only channeled the inside. The outer edge of the soffit gets stapled in the V grooves to the bottom side of the gutter or fascia boards. Then I would bend aluminum coil stock to cover the fascia and the cut edge of the soffit. The bend has to be greater than 90 degrees, it should match the slope of the soffit so it sits flush against the soffit. I still have a trim table made for cutting siding material. You don't have to turn the blade backwards. Wear mechanics gloves or by the end of the day your hands will be shredded with cuts from the aluminum. 
Mike Hawkins:smile:


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## craig11152 (Jun 20, 2015)

I would remove the plywood and use vented soffit all the way across assuming you have attic space you want to vent.


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## PatChap (Nov 17, 2012)

craig11152 said:


> I would remove the plywood and use vented soffit all the way across assuming you have attic space you want to vent.


If the plywood soffits are in good shape, it may be easier and sufficient to cut a 8-10" wide strip out of the entire length.
Removing it entirely is best, but depending how the overhangs were built may add a lot of work.


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## craig11152 (Jun 20, 2015)

PatChap said:


> If the plywood soffits are in good shape, it may be easier and sufficient to cut a 8-10" wide strip out of the entire length.
> Removing it entirely is best, but depending how the overhangs were built may add a lot of work.


true but I'd rather jerk down a 3/8" piece of 12-24 inch plywood than run a saw upside down and get all that saw dust down my neck. :wink2:


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## mako1 (Jan 7, 2014)

PatChap said:


> If the plywood soffits are in good shape, it may be easier and sufficient to cut a 8-10" wide strip out of the entire length.
> Removing it entirely is best, but depending how the overhangs were built may add a lot of work.


It would not be less work if the op intends to do it correct.Would you like to take a saw and cut a 8-10" strip out of the center of a soffit?You would then need channel on each side of a closed cut to accept the soffit .How would you attach it?How would you get the soffit in the space and still have the channel on the other side?I guess you could just cut some soffit material and staple it up with no channel?That would be lovely.
You could cut the center out,overhead and leave one end open.Nail the channel to both sides and slide each piece in and try to connect them and then fight the other end in maybe?
There is a reason things are designed as they are.Usually for ease of installation and integrity of the structure.I have not seen anyone reinvent the wheel lately. JMHO


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## PatChap (Nov 17, 2012)

It installs in the same manner whether the plywood is there or not.
You attach the j or f to the inside, slip the soffit in and nail or screw it to the fascia. The fascia is then wrapped with aluminum.
I'm not sure what sort of installation your describing.


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## mako1 (Jan 7, 2014)

You are correct.I had seen pics or posts today about a center section cut out.That is what I was referring to.Could have been another post or a double .Who knows.
Still not a lot more trouble or expense to do it correct as you have already stated.


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