Diagonal beams below ceiling joists.. are they needed?

[digdug]

Hello,

I have a 18X20 garage that I am thinking about finishing and I have these beams that go diagonally across the entire span (making an X) right below my ceiling joists. Do I need these beams or are they left over from the original framing process (probably around 1939). If they are needed is there anything I can add to replace their function (like maybe brackets and/or braces) that wouldn't make the ceiling not so awkward to panel.

Thanks!
Doug

 

[Stuart in MN]

I can only assume they are there to keep the building from racking. There aren't very many cross ties / ceiling joists, and by the way the two beams are notched together I would also assume they were meant to be permanent.

 

[digdug]

Thanks for the feedback! I wouldn't mind adding more cross ties if it meant I could get rid of these beams. Right now there are just two.. the one you can see in the picture and one just like it on the other side.

 

[FordTruckWench]

I wouldn't mind adding more cross ties if it meant I could get rid of these beams. Right now there are just two.. the one you can see in the picture and one just like it on the other side.

Adding cross ties won't take over the function of the diagonals. With your shake roof, the building has no shear strength keeping it square. You don't even have 1x6 sheathing. (A modern building would have sheets of plywood that would keep the roof deck from racking - and by extension, they'd keep the entire building square.)

Once you install ceiling joists, you could install a plywood deck on top of them that could take over from the diagonals. Even drywall on the underside of the joists has some shear strength.

 

[dfiler2]

If you put in cross ties and a ceiling of plywood or metal panel liner, it would do the job that the cross ties are doing now.

 

[laser3kw]

Once you install ceiling joists, you could install a plywood deck on top of them that could take over from the diagonals

^^^ this^^^
if you are going to improve, that will add a lot of stiffness.

 

[Homerr]

Except plywood also implies storage load capacity, which isn't the case.

 

[28HopUp]

Instead of paneling the ceiling, you could paint the underside of the structure and leave it open for a commercial/industrial look. There's a lot of detail work that would look good if left exposed. You could also place lights atop the X bracing that throws light up onto the exposed ceiling. Justa thought...

 

[K'ledgeBldr]

Install ceiling joists at every rafter. Tie the rafter to the ceiling joist and the ceiling joist to the top plate. After they are all in you could "safely" remove the X-brace without racking the structure. You could also put some diagonals across the top of the ceiling joists for "extra diagonal support".

Now you're ready for a drywall or other substance for a finished ceiling.

 

[Nowater]

Could you put the cross ties above the joists? I can't see in the photos.

 

[firebirdparts]

Those braces don't really do anything that the walls and roof aren't already doing. Since you're in LA and have earthquakes, anything extra there is probably good. I'm no expert on that.

What you really need is ceiling joists. Especially with that low pitched roof, you have a lot of stress on the structure. The x bracing does nothing to help with that. The building has survived the stress because it was so small.

 

[Vintage Veloce]

Leave the "X" exposed! Sheet rock between or above them, and leave the xposed beams, it will look excellent. Just don't lose the cool old look.
In my 1926 garage I sheetrocked the walls and finished them and left the ceiling open. Looks great.

 

[Vintage Veloce]

Like this, leave it exposed...

 

[FordTruckWench]

Those braces don't really do anything that the walls and roof aren't already doing.

Except that the roof itself has no diagonal strength. It is wood shakes on spaced out 1x4 laths. (This is the correct - shake roofs need to breath from the bottom to dry out properly.)

If the roof were asphalt shingles nailed to a deck of 1x6's, then the boards would provide at least some shear strength: Any diagonal racking would cause the 1x6's to press against each other thus stopping the racking. (Of course, after installation, the boards would dry out and shrink, thus opening a small gap. This gap would allow some movement before the boards bind up.)

Who knows how much shear strength is in the walls - at least I do see a diagonal brace.

 

[digdug]

Thanks everyone for the good ideas. I am starting to lean towards keeping the ceiling open.. but redoing the roof.. with a plywood deck for added strength.. (looks like I have asphalt shingles over my wood shingles.. and the asphalt shingles are on the old side). I would then add additional ceiling joists (remove the diagonals) and then panel the rafters with horizontal beadboard.. then drywall the back wall and above the door all the way up (along with the rest of the walls). I am trying to make the space inviting for my wife as we will be using some of the space for a gym and if I keep the rafters unfinished and old school I have a feeling she will never go in.. thinking a spider or some creepy crawler will fall down on her ( I am sure for some that would be a feature not a glitch). Who knows maybe just drywall on the walls will be enough for her... we shall see.

Has anyone done horizontal beadboard panel on the rafters?

Thanks again!

 

[APEowner]

While I'm sure you could re-frame and/or skin the roof to eliminate the need for those x-braces they're such a cool architectural detail that I'd leave them. I'd drywall above them to make them a feature.

 

[FordTruckWench]

While I'm sure you could re-frame and/or skin the roof to eliminate the need for those x-braces they're such a cool architectural detail that I'd leave them.

They're also old growth redwood!

I think it would be cool to fill the space between the rafters - but leave the bottom surface of each rafter exposed. Something like https://en.wikipedia.org/wiki/Timber_framing#Half-timbering

 

[wrenchguy]

Hello,

I have a 18X20 garage that I am thinking about finishing and I have these beams that go diagonally across the entire span (making an X) right below my ceiling joists. Do I need these beams or are they left over from the original framing process (probably around 1939). If they are needed is there anything I can add to replace their function (like maybe brackets and/or braces) that wouldn't make the ceiling not so awkward to panel.

Thanks!
Doug

from what i can see excellent craftsman's labor there. ur in warm california, clean, repair and use as is. looks 2b aged pine 2me.

 

[Handyfarmer]

one could run diganals under the rafters them selves, that would keep it from raking as well and the "x brace " could be removed, the diganals could be 1x4 materials or 1x6, run them from the corners to the middle of the peak of the building,

Or one could strip the roof and plywood it and reshingle it,


keeping the cross ties "collars" would be a good thing, keeps the building from spreading,

 

[acer66]

Like this, leave it exposed...

That looks great.

 

[FullRaceMerc]

You should leave them. Because of the large opening for the garage door, that end of the building doesn't have enough shear on its own to prevent it from leaning to the side.

Think of trying to push a sealed cardboard box to the side. Then think of how much weaker the same box is with one open end. Garages need to compensate for the open end. Those diagonal ties hold the front corners of the garage from pushing over.

New garages will use a "strong wall" product anchored into the footing on the sides of the door to do that job today. Or they have a larger flat surface beside the door to provide shear on that end.

Instead of taking them out, how about furring down the rafter ties (ceiling joists) to match the bottom height of those diagonal ties? A 2x4 added flat on the bottom of the rafter ties would allow you to have a flat ceiling & still keep the structure intact.

As mentioned above, you will need to add more ceiling joists, because they are currently too far apart to support a ceiling. Also rafter ties are designed to keep the top of the walls from being pushed out by the rafters under the load of the roof. So they are usually big enough to hold the sides together, but not necessarily big enough to support a ceiling over that span. Its probably a good idea to sister some taller lumber along side of the existing rafter ties & for any new ones you add. The tricky part is sneaking the new ones in while keeping the existing roof in place. If you are doing a new roof, that's a great time to add them.

 

[FullRaceMerc]

Your other thought to add beadboard to the bottom of the rafters instead sounds like it might work better anyway. You could caulk & paint it to give that sealed ceiling feel, but still keep the extra height that makes the garage feel roomy. Garages with flat ceilings can sometimes feel cramped. With only the few rafter ties & diagonal bracing exposed, the room should feel a lot less "spidery" to your wife. You could also paint those remaining exposed pieces if needed.

Btw, I think it looks cool the way it is. But as Jeff Allen said, happy wife, happy life. If it's a shared space it needs to work for both.

 

[Vintage Veloce]

That looks great.

Thanks!

Here is another pic. My building was bult in 1926 and is all old growth Redwood that was in bad shape. The 2x6 bottom chords are new and were added along with the verticals to help support the roof. They are douglas fir that I sprayed with stain to match the rest of the redwood. You can also see on the right new rafter tails that were sistered in to replace the old rotted ones, but those were done in new redwood.
Tip: Stain the wood first befoe installing it. Spraying stain inside the garage is highly toxic!

 

[Vintage Veloce]

Another note, that old stuff you have is probably dimensional. (Meaning real 2 x4 or 2 x3 measurements, not the skimmed stuff they sell today. Really, keep that stuff and show it off. It's historic!

 

[acer66]

Thanks!

Here is another pic. My building was bult in 1926 and is all old growth Redwood that was in bad shape. The 2x6 bottom chords are new and were added along with the verticals to help support the roof. They are douglas fir that I sprayed with stain to match the rest of the redwood. You can also see on the right new rafter tails that were sistered in to replace the old rotted ones, but those were done in new redwood.
Tip: Stain the wood first befoe installing it. Spraying stain inside the garage is highly toxic!

Thank you that is what I needed.
Not sure when my garage was build but it has real 2x but the bottom chords
are either new or very sagging naild together real 2x so I will do what you have.

 

[digdug]

I am starting to lean towards keeping all the beams as they are... and maybe just put the beadboard between the rafters.. so the rafter beams will still be exposed. I do agree that putting in a ceiling at the standard height will make the space feel much smaller. I think paneling between the rafters will accomplish the goal of reducing the "spooky" factor. I can always give it a try and see how it looks.. plus it is least amount of work

On a side note, the lumber is about a 1/4 inch larger in both dimensions than current 2X4s. The wood also feels denser than current 2X4s. Is the reddish color from pine aging.. or did they make 2X4s out of different wood back in the 30's?

Thanks again for all the ideas/input!

 

[Vintage Veloce]

It's likely Redwood.

 

[acer66]

On a side note, the lumber is about a 1/4 inch larger in both dimensions than current 2X4s. The wood also feels denser than current 2X4s. Is the reddish color from pine aging.. or did they make 2X4s out of different wood back in the 30's?

They used various locally available wood types back then,
a friends house has a lot of oak in the framing.

 

[acer66]

If you can not hide it show it.