[seephor]

I have a 20' by 20' room that currently has a partial wall 8' in from one side that only serves to support one end of the ceiling joists and Sheetrock. No other load exists on this wall besides the joists and Sheetrock as I tripple checked from the attic. My intention is remove this wall and install a hidden beam and hang the ceiling joists from it.

All beam span charts I've come across are for loads such as floors or roofs. How would I go about sizing this beam? I was thinking of just going overkill to be safe but can someone give me an idea of what they would recommend?

Again, no live load, only dead load consisting of joists, Sheetrock and insulation.

This is a 20' span. I've attached an illustration.

 

[Californiadecks]

I have a 20' by 20' room that currently has a partial wall 8' in from one side that only serves to support one end of the ceiling joists and Sheetrock. No other load exists on this wall besides the joists and Sheetrock as I tripple checked from the attic. My intention is remove this wall and install a hidden beam and hang the ceiling joists from it.

All beam span charts I've come across are for loads such as floors or roofs. How would I go about sizing this beam? I was thinking of just going overkill to be safe but can someone give me an idea of what they would recommend?

Again, no live load, only dead load consisting of joists, Sheetrock and insulation.

This is a 20' span. I've attached an illustration.

The problem isn't so much the load (which counts of course) but a beam that long has a tendency to sag under its wieght even with nothing on it. I'm pretty sure you'll need an engineered beam for that span.

 

[seephor]

The problem isn't so much the load (which counts of course) but a beam that long has a tendency to sag under its wieght even with nothing on it. I'm pretty sure you'll need an engineered beam for that span.

Right, it's the sagging over time I'm worried about. I was thinking of sandwiching 3/4" plywood with two 2x10's glued and lag bolted.

 

[Californiadecks]

Right, it's the sagging over time I'm worried about. I was thinking of sandwiching 3/4" plywood with two 2x10's glued and lag bolted.

I'd look into an lvl beam. They really aren't priced as bad as one might think. And I'd use a material lift like this to install it, which can be rented for about 60 bucks.

The forks can be turned around to get zero clearance at the ceiling.

 

[jimn]

Beams are sized according to load. It's always best to have an on site structural engineer look at structure such as this and advise on not only a beam of the appropriate design and material but also how to properly support the beam . It's a an engineered system and not just lets put some kind of beam up without knowing what you need.

 

[Mingledtrash]

Beams are sized according to load. It's always best to have an on site structural engineer look at structure such as this and advise on not only a beam of the appropriate design and material but also how to properly support the beam . It's a an engineered system and not just lets put some kind of beam up without knowing what you need.

jimn01 is right you need more than just a beam you need support columns and foundation that are engineered for the point loads.
2-2x10 with 3/4 ply is woefully undersized for this. I looked up some span tables, your going to be between a 12 in. and 18 in. lvl either 2 or 3 ply depending on size. Another thing you need from an engineer is the fastener schedule.

Oh, one more thing, it still has to be calculated for a live load everything do.

 

[Californiadecks]

Ceiling joists and drywall. Meh. I would get an engineered beam. (They will calculate the load for the size of beam) I probably wouldn't start jackhammering footings. In fact out here we can put up to 750 lbs on each post with just slab on grade and no footing. You have wall footings that are existing that will be more than enough. Imo. I'll bet the beam will wiegh 200lbs.

 

[Aggie67]

Right, it's the sagging over time I'm worried about. I was thinking of sandwiching 3/4" plywood with two 2x10's glued and lag bolted.

That won't do you any good.

 

[seephor]

Thanks for the information. I think I'll go with a sized LVL. The two point loads are on top of concrete footings so that shouldn't pose a problem. I calculated roughly 840 lb of load spread evenly across the beam so about 400 lb of load per point on the foundation.

Can you guys give me a better idea of the sizing of this lvl now that I have the load and span?

 

[Californiadecks]

Thanks for the information. I think I'll go with a sized LVL. The two point loads are on top of concrete footings so that shouldn't pose a problem. I calculated roughly 840 lb of load spread evenly across the beam so about 400 lb of load per point on the foundation.

Can you guys give me a better idea of the sizing of this lvl now that I have the load and span?

I'd speak to your lumber rep.

 

[Daniel Holzman]

I am a bit confused by this thread. You say the only load on the beam is the dead load of the joists, plus some drywall (presumably ceiling). So are you saying the joists are only there to provide an attachment point for the drywall? There is no storage space above, no possibility of putting a room up there? Normally loads are code driven by the use type, so for example a common live load for a bedroom would be 30 psf, for an attic with storage only might be 10 psf, for a deck might be 40 psf, you get the idea. Even if you only have storage above, you would still likely need to design for 10 psf live load, of course your building inspector will be happy to discuss required loading with you when you pull the permit. The beam needs to be designed at a minimum for the code required load.

 

[seephor]

I am a bit confused by this thread. You say the only load on the beam is the dead load of the joists, plus some drywall (presumably ceiling). So are you saying the joists are only there to provide an attachment point for the drywall? There is no storage space above, no possibility of putting a room up there? Normally loads are code driven by the use type, so for example a common live load for a bedroom would be 30 psf, for an attic with storage only might be 10 psf, for a deck might be 40 psf, you get the idea. Even if you only have storage above, you would still likely need to design for 10 psf live load, of course your building inspector will be happy to discuss required loading with you when you pull the permit. The beam needs to be designed at a minimum for the code required load.

Daniel,

Yes, you are correct, there's only an attic space with no storage. 10 psf is the minimum live load to consider for such a case. The dead load is no more than 5 psf after calculating the weight of drywall, joists and insulation.

 

[seephor]

I consulted with an engineer and he took account 10 psi live and 5 psi dead load and came up with a 4x16 dimensional lumber in southern pine for the span

Can someone give me an equivalent size for an lvl or other options?

 

[Californiadecks]

I consulted with an engineer and he took account 10 psi live and 5 psi dead load and came up with a 4x16 dimensional lumber in southern pine for the span

Can someone give me an equivalent size for an lvl or other options?

Ask your lumber rep to give you an equivalent. It should be an easy find for him. Probably in his book or just a phone call.

 

[seephor]

Ask your lumber rep to give you an equivalent. It should be an easy find for him. Probably in his book or just a phone call.

Thanks. I found the equivalent on an online table. I honestly don't like talking to the lumber yard reps if I absolutely don't have to. If you're not a GC who purchases thousands from them monthly, they treat you like you don't know anything and have very limited patience with low volume customers.

 

[Californiadecks]

Thanks. I found the equivalent on an online table. I honestly don't like talking to the lumber yard reps if I absolutely don't have to. If you're not a GC who purchases thousands from them monthly, they treat you like you don't know anything and have very limited patience with low volume customers.

Good luck. The worst case scenario is it might sag a little. Unless you grossly undersize it I don't see a saftey issue. It might not hurt to bump it up another size just for a little insurance. :thumbsup:

Edit: Be sure to use proper post to beam connections.