Building a loft?

[Adittmer]

I'm looking for some info on different ways I can build a loft above a bedroom & bathroom/utility room in a barndominium I am finishing off myself.

My thoughts are now to maybe just attach a 2x12" ledger board to my out side wall posts then use joist hangers to run 2x12"s out 14' and rest them at 12ft on a 2x8" load bearing type wall.



I don't have the best pictures of it but it would be on the right side of where the photo shows.
Loft will be the width of the living space 24' and be 14' deep.

The building is built using 3ply 2x8" on perma columns and post are spaced 8ft on center




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[Adittmer]

Never mind the first picture it's the right side of the second picture is where it's going


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[Adittmer]

Here is the floor plan, loft goes above the first floor rooms


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[Chris705]

Your general thought is a solid one. 2x12s @ 16"oc spanning 14' will be solid. Maybe even a bit overkill for a bedroom/bathroom area (30 psf). And a bearing wall to support the mid span of the floor joists works also.....it can even be 2x4@16"oc. But understand if you want a wet wall for plumbing coming down from above, you could also use a 2x6 wall or even a chase wall. Where a bit more thought is needed is at the 8' span between columns. A single 2x12 "ledger" board seems a bit light, a single lvl might work, I'd need to figure out the loading on that member. To calculate that load figure the sf of area the 8' long ledger supports....8' x half the joist span of 14' which is 7'.... 8' x 7' = 56sf. 56x30psf = 1680 pounds (uniformly supported) by the ledger. A lvl chart will tell you what size @ 11.25" deep works to support that load.

 

[Adittmer]

So do you guys think the outside post that I'm adding the ledger board to spaced 8ft on center are strong enough to support the weight of the loft and the roof/ building??


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[Chris705]

Where are you located? How much snow load?

I'd have to know a lot more about your build....post sizes, footing sizes etc. did any professional look at your plans or how was it permitted?

I'd like to think the posts are capable of supporting both loads yes...

 

[larry_g]

If you look at my build below you can see that I did what your proposing. 2x12 ledger on the posts and the other end on a support wall.

lg
no neat sig line

 

[theoldwizard1]

So do you guys think the outside post that I'm adding the ledger board to spaced 8ft on center are strong enough to support the weight of the loft and the roof/ building??

ABSOLUTELY NOT !!

Build full support (2x4 16" OC) underneath you "ledger". This need to sit on a PT footer on top of you floor.

 

[Adittmer]

Where are you located? How much snow load?

I'd have to know a lot more about your build....post sizes, footing sizes etc. did any professional look at your plans or how was it permitted?

I'd like to think the posts are capable of supporting both loads yes...

Building is in northern Wisconsin I wanna say snow load is 42. The size of building is 36x72' with 17ft walls and 4/12 roof. Post are 3 ply 2x8" and we used perma columns for the footings. Holes are dug 4ft deep 2ft auger bit then sack Crete in the bottom then set with more sack Crete the. Backfilled with fill.


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[Chris705]

All side wall posts are at 8' oc? 2' auger... was bottom of hole clean at edges or lots of loose soil at bottom edges? This hasn't been thru a winter yet? The black brackets that hold the top of post, truss bearing member in place...did you plan on using those to support the loft ledger in place? What size and type member is the truss support?

 

[psu927]

ABSOLUTELY NOT !!

Build full support (2x4 16" OC) underneath you "ledger". This need to sit on a PT footer on top of you floor.

I would disagree, the post should be more than adequate to support the additional load of a loft.

 

[Chris705]

Before I concur I need more input from the OP.

 

[Adittmer]

The holes looked like this or at least the ones by the large overhead door in the gable end. It's going through it's first winter right now. I really don't know how I'd attach the ledger board, maybe 1/2 lag bolts into the posts but I'm not sure that's a great idea either because they are laminated 3ply 2x8' and I don't want them to delaminate etc


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[larry_g]

http://www.garagejournal.com/forum/attachment.php?attachmentid=80115&d=1286472061

In the picture above you can see the support under the ledger board in mine. The ledger is nailed to the post and the support board is also nailed and it was specked to have 12 (or 20) nails in it, 20p nails.

lg
no neat sig line

 

[Duker]

I am in the midst of planning this for my 42x40 living space section within our barndominium. I am going to use engineered trusses to build the loft that way I can run ductwork through the trusses instead of losing wall or ceiling space. The cost appears to a minimal increase versus the flexibility it will give. I will have the loft on both the living space and my workshop. Just tossing out an idea to consider if it makes sense in your situation.

*

 

[Adittmer]

I am in the midst of planning this for my 42x40 living space section within our barndominium. I am going to use engineered trusses to build the loft that way I can run ductwork through the trusses instead of losing wall or ceiling space. The cost appears to a minimal increase versus the flexibility it will give. I will have the loft on both the living space and my workshop. Just tossing out an idea to consider if it makes sense in your situation.



*

I built the walls 17' tall that way I would have a 24x24' living area/ kitchen vaulted & then Frame out my bedroom and bathroom with the leftover 12x24' and above that part is where the open loft will be not above the ceiling in the trusses of that makes sense. I am by no means a contractor lol, I came up with this plan to build this barndominium while sitting at the kitchen table drinking Jim beam & cokes lol. There are things I wish I would have done differently but by & large I'm happy with what I have and am thankful for how it's turned out so far!


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[Adittmer]

I built the walls 17' tall that way I would have a 24x24' living area/ kitchen vaulted & then Frame out my bedroom and bathroom with the leftover 12x24' and above that part is where the open loft will be not above the ceiling in the trusses of that makes sense. I am by no means a contractor lol, I came up with this plan to build this barndominium while sitting at the kitchen table drinking Jim beam & cokes lol. There are things I wish I would have done differently but by & large I'm happy with what I have and am thankful for how it's turned out so far!


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[bczygan]

I'm looking for some info on different ways I can build a loft above a bedroom & bathroom/utility room in a barndominium I am finishing off myself.

My thoughts are now to maybe just attach a 2x12" ledger board to my out side wall posts then use joist hangers to run 2x12"s out 14' and rest them at 12ft on a 2x8" load bearing type wall.



I don't have the best pictures of it but it would be on the right side of where the photo shows.
Loft will be the width of the living space 24' and be 14' deep.

The building is built using 3ply 2x8" on perma columns and post are spaced 8ft on center




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This needs to be engineered, so let's do it.

First, a couple of questions.

What are you storing on this mezzanine?

Why are you cantilevering past the supporting wall?

And why a 2x8 wall? It only needs to be 2x4.

Bill (Designer)

 

[Adittmer]

This needs to be engineered, so let's do it.



First, a couple of questions.



What are you storing on this mezzanine?



Why are you cantilevering past the supporting wall?



And why a 2x8 wall? It only needs to be 2x4.



Bill (Designer)

Well the loft/mezzanine is living space for some beds maybe a couch, a table maybe etc. It will be a place for my derelict buddy's and maybe there wives to sleep on weekends / durn hunting season.

My plan to build the load bearing wall out of 2x8's is part of me wanting it to be a brick **** house and also to hide plumbing, I will not build it from 2x4's lol, might go 2x6's tho.

Reason to cantilever the floor joists is to have more room.




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[bczygan]

As an example, let's assume a floor loading like a typical residential space. That would be 40#LL and 10#DL. Using #2 and better hem-fir joists, spaced at 16"o.c. and using a L/360, you can span the 12' with 2x8's. They will also work with the 2' cantilever. Use 3/4" T&G plywood decking staggered and glued and screwed. Use solid blocking at the midpoint.

The ledger is a beam with a contributing area of 6SF, so the load on it is 300#/LF. The span is 8'. A #2 and better hem-fir 2x12 will support 362#/LF, so is adequate for this case.
Attention should be paid to the fastening and support of this ledger beam. I would lag bolt it with at least 2 3/8" lag bolts at each column and support it with a 2x6 or wider fastened to the face of each column.

Understand?

BTW, this will work for the loads you plan. There won't be a wall sitting on the end of the cantilever, will there? It will be open, right?

Bill

 

[Adittmer]

Aa an example, let's assume a floor loading like a typical residential space. That would be 40#LL and 10#DL. Using #2 and better hem-fir joists, spaced at 16"o.c. and using a L/360, you can span the 12' with 2x8's. Use 3/4" T&G plywood decking staggered and glued and screwed. Use solid blocking at the midpoint.

The ledger is a beam with a contributing area of 6SF, so the load on it is 300#/LF. The span is 8'. A #2 and better hem-fir 2x12 will support 362#/LF, so is adequate for this case.
attention should be paid to the fastening and support of this ledger beam. I would lag bolt it with at least 2 3/8" lag bolts at each column and support it with a 2x6 or wider fastened to the face of each column.

Understand?

Bill

Most of that makes sense, some of it not so much. My plan is to use 2x12"s for the floor joists and it sounds like what your saying that should be fine. I would lag bolt it using larger lags like mentioned.

Would I be better off just framing 2x8 walls 8ft tall to fit between my columns and resting my floor joists on them?


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[bczygan]

Most of that makes sense, some of it not so much. My plan is to use 2x12"s for the floor joists and it sounds like what your saying that should be fine. I would lag bolt it using larger lags like mentioned.

Would I be better off just framing 2x8 walls 8ft tall to fit between my columns and resting my floor joists on them?


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No.

Do exactly as I say above. Tell me what parts you don't understand. You must use the exact species and grade and size and spacing specified to get the strengths required.

It is a waste to use more or bigger members than required. Wasteful. And doesn't make the structure any stronger. Your structure is only as strong as it's weakest part, so making the joists deeper doesn't do you any good. The limiting factor would be the ledger.

It is important that you understand that you need to not just fasten the ledger, but to support it with a 2x6 under it, attached to the face of each column. This 2x6 is a column running from under the ledger, down to the floor and securely fastened to the building column. Also no wall at upstairs at the end of the cantilever, right? Just a railing. And where is the stair for access?

Understand?

Bill

 

[bczygan]

How are you finishing off these rooms inside?

Insulation? Heating and cooling?

Bill

 

[rpcraft]

Can't wait to see how this turns out. My idea home would be an apartment sized place/loft over a garage that allows me to work in an AC and heated facility and never have to go far to the living stuff!!!!

 

[Adittmer]

The loft will have a railing and I'm thinking of doing steel welded spiral stairs.

Only the outside walls will be insulated. Heating will be wood stove and heated flooring via boiler & pex in 5in stamped colored concrete.

Are you saying just use 2x8s for joists and span 12' and also cantilever 2'? Not 2x10s or 2x12s????


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[bczygan]

If you are insulating and drywalling thes first floor rooms, then outside wall framing might be a better way to go, since you need the framing for drywall to enclose the insulation. In that case, the ledger disappears. Again it is just wasteful to use more than a 2x4 wall. All these walls should have double top plates and openings below should have adequately sized headers where they are bearing walls.

Understand?

Bill

 

[bczygan]

The loft will have a railing and I'm thinking of doing steel welded spiral stairs.

Only the outside walls will be insulated. Heating will be wood stove and heated flooring via boiler & pex in 5in stamped colored concrete.

Are you saying just use 2x8s for joists and span 12' and also cantilever 2'? Not 2x10s or 2x12s????


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YES!
They must be #2 and better hem-fir spaced 16" on center. Rim joists at the ends and solid blocking at midspan.

This is based on a joist span calculator you can see here:
http://www.awc.org/codes-standards/calculators-software/spancalc


This is also based on a L/360, so deflection would be .4". This is good enough for a drywall ceiling below. If you want it even stiffer, go with 2x10's or a stronger species or grade of lumber. Put camber up.



Bill

 

[madoc1]

i earlier saw you building thread and just saw this one. i think busy makes the most sense. since you will be insulating the out side wall you might as well build a 2x4 inside supporting wall instead of a ledger. you will only lose 4" of floor space and can super insulate it. it will also fulfill the purpose of adding the necessary support for your wall finish, which you will need anyway.

jim