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Load and span information

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Forum topic by Dan Morgan posted 02-26-2016 11:27 PM 609 views 0 times favorited 16 replies Add to Favorites Watch
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Dan Morgan

48 posts in 590 days


02-26-2016 11:27 PM

I didn’t know where else to put this question…

The wife has decided that the next project for the house is raising a sunken living room.

The height the floor needs to be raised doesn’t allow for me laying dimensional lumber on the e existing floor so I’m looking for load/span information and not doing too well.

Anyone have a quick link to share?

Thanks

-- Maintenance Man - I do precision guesswork based on unreliable data from people of questionable knowledge...


16 replies so far

View fisherdoug09's profile

fisherdoug09

121 posts in 2137 days


#1 posted 02-26-2016 11:41 PM

I would check with your local lumber yard that caters to builders. They usually have that type of info for beam span and sizes so they should be able to help you.

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David Taylor

326 posts in 549 days


#2 posted 02-27-2016 12:28 AM

The American Wood Council has a span calculator here – http://www.awc.org/codes-standards/calculators-software/spancalc

I’m wondering, though, if you have to raise it high enough to not be able to lay the lumber on the floor, can you put in supports that do go down to the floor, or more specifically, the structure of the floor? That would help with the spans.

-- Learn Relentlessly

View Dark_Lightning's profile

Dark_Lightning

2633 posts in 2571 days


#3 posted 02-27-2016 04:44 AM

Get the Uniform Building Code sheet from your local Building and Safety office. You’ll have to pull the permit there, anyway, if you are making a permitted change to your home. Where are you, generally, geographically speaking? The codes vary (though they shouldn’t, IMO, but should be written for maximum human safety everywhere). If you don’t want to share your location, I understand.

-- Random Orbital Nailer

View splatman's profile

splatman

558 posts in 861 days


#4 posted 02-27-2016 05:19 AM

The Sagulator. For designing shelves, but works for beams, too. Read the notes on the site on how to do so.
Be sure to check with authorities with whatever you come up with, to keep you out of trouble.

View rwe2156's profile (online now)

rwe2156

2192 posts in 943 days


#5 posted 02-27-2016 11:11 AM

How deep? How big?

If its over 12’ you’ll need a support beam in the center.
2×8’s are pretty standard floor joists.
My rule of thumb on floors is you can never build them too stout.

The last thing I would do is pull a permit, but that’s me. Personally, I wouldn’t let an inspector in my house.

When my brother had to pull a plumbing permit to move a washing machine (a neighbor turned him in) the inspector ended up interrogating him about his kitchen cabs (which he installed himself). All because he asked him whats on the other side of the wall?

I did pull a permit for an addition on our house, but for minor remodels, NO.

-- Everything is a prototype thats why its one of a kind!!

View Tennessee's profile

Tennessee

2410 posts in 1976 days


#6 posted 02-27-2016 11:30 AM

A permit for raising a floor in a sunken living room where you cannot use standard dimensional lumber but need higher? Most living rooms I have seen in those types of houses has to be at least 12X12, probably larger.

I see architectural drawings, building engineer sign offs, housing permit signoffs, electrical signoffs, (have to raise the outlets and switches!), and anything else they can think of. And if your wife ends up not liking the position of the windows when the floor is raised, you are then looking into changing the heights of the windows, and that entails outside visuals, which could morph into them interpreting it as a complete addition. I do NOT envy you…

It might end up costing more time and money to get all the permits, drawings and proper signoffs than it would to just find one of the suggested calculators above and quietly start buying lumber.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View REO's profile

REO

889 posts in 1536 days


#7 posted 02-27-2016 01:18 PM

If you are just bringing it up to be level with the rest why not just lay in sleepers and new sheeting?

View dhazelton's profile

dhazelton

2324 posts in 1759 days


#8 posted 02-27-2016 02:04 PM

I always go with an inch of lumber per foot of span, so a 6 ft span could be done with 2×6s 16 on center. If you have a 12 ft span and width as someone hypothesized put a 2×12 (or a double up one if it makes you feel better) in the center and hang 2×6s perpendicular off that, and stick in some posts if you feel it’s necessary. If your space is deep enough put a large trap door in there to gain some storage.

View Dan Morgan's profile

Dan Morgan

48 posts in 590 days


#9 posted 02-27-2016 02:12 PM

I’m in Boise Idaho.

Thanks for the link on the calculator.

I’m always a fan of over-building everything, nothing I hate more than a squeaky floor.

I can get away with no permit since it’s such a simple change with only cosmetic differences.

My goal is to stay off the floor, it’s a concrete slab and I will insulate and such but I’m thinking if I come off the floor I run the risk of drawing the cold up from the concrete. Maybe I’m worried for nothing?

-- Maintenance Man - I do precision guesswork based on unreliable data from people of questionable knowledge...

View Dan Morgan's profile

Dan Morgan

48 posts in 590 days


#10 posted 02-27-2016 09:59 PM

No should also add, the span is 10’ 5” and the depth is 7”. So I know I can rip to exact width but I’m trying to avoid that.

Am I too worried about “wicking” cold up from the cement floor?

-- Maintenance Man - I do precision guesswork based on unreliable data from people of questionable knowledge...

View dhazelton's profile

dhazelton

2324 posts in 1759 days


#11 posted 02-27-2016 11:09 PM

Are your feet cold now? If not they will be less so with wood as a thermal bridge.

View AZWoody's profile (online now)

AZWoody

693 posts in 686 days


#12 posted 02-27-2016 11:14 PM

I would just use 2×6 on maybe 12” centers horizontally with 2×4s every foot vertically as legs to adjust the height off the floor, then cap it with a 1 1/8 plywood floorboards.

I did something similar but using only 2×4s to make a riser for a home theater and it’s very solid and the 2×4s are I believe on 2 foot centers.

View Snipes's profile

Snipes

94 posts in 1707 days


#13 posted 02-28-2016 02:27 AM

3/4” foam, 5 1/2”joist, 3/4” subfloor

-- if it is to be it is up to me

View Dan Morgan's profile

Dan Morgan

48 posts in 590 days


#14 posted 02-28-2016 02:38 AM

Mmmmm…..hadn’t thought about foam board. I could use the stuff with a reflective back. Now that’s a spanking good idea.

-- Maintenance Man - I do precision guesswork based on unreliable data from people of questionable knowledge...

View REO's profile

REO

889 posts in 1536 days


#15 posted 02-29-2016 03:16 AM

If you use the foam under the sleepers and they aren’t rated for the span the foam will compress under load and you will get a spongey floor. Use an inverted “T” arrangement with a 2x stock to disperse the load and get the higher density foam to start with. Or you could lay down foam and cover with sturdi-span then the sleepers then the decking.

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