Hey guys.
I'm redoing an old house and since it's so small (58m2/620sqft), I'm planning to make the first story a single room. However, I'm not sure if I will be able to make the ceiling/floor of the attic stable.
Currently the construction of the ceiling consists of 5x15cm (2x6 inch) joists. The longest a joist goes without support is 2,3m (7,5ft) in the current setup. It rests on a fireplace which I have demolished (pic related, the one that is further from the camera no longer exists). Would it be fine to replace it with a beefier beam and extend its unsupported length to 5,1 meters (16,1ft)? Or must I install a support post in place of the old fireplace? Keep in mind that the attic will also be used as a room, so it must be sturdy.
Thanks engineer bros.
Not a structural engineer or experienced in this but from here
http://www.5startimbers.com.au/downloads/HYSPAN-EWP-SPAN-GUIDE-FOR-RESIDENTIAL-FRAMING.pdf
I think that you’d be looking at something like a 240x45mm beam for the scenario where you’re supporting floor loads only.
Apart from the educated answer,
floor joists have to be supported by rim or bridge joists. No e.g. sistering to extend the length of a joist. You'd probably have to put in a couple vertical beams that transfer loads from above, to shoring underneath, with a horizontal across the top. Do not put a beam over a portion of the floor that isn't directly supported underneath.
This one.
For example if you have a bearing wall on the right, it's carrying the roof load with the exterior walls. Underneath it will be a beam and footings into the foundation. To remove anything bearing, it must be replaced with structure, so lvl beam for example.
Interior walls parallel to the joists that just divide rooms are fair game.
There are already rim joists around the whole perimeter of the house. As for the bridge joists, I am planning to install them.
Well that furnace and the wall connected to it was load bearing I'd say, as the joist was resting on top of it. But why can't I just install a beefier joist and not support it with anything from below?
This looks very useful, thanks.
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For a 16' span you can use 2x10's at 12" on center or 2x12's at 16" on center. This is for typical/standard framing lumber which is usually graded #2, with a live load of 40 lb/sqft which is what IRC stipulates for general living areas.
However this is for the US, I don't know how lumber is graded in other areas of the world, whether the standard for framing lumber is the same elsewhere as it is here.
I'm back with something I drew up. This is a plan I came up with after researching joist span tables, types of blocking and so on. The problem is that I'm struggling to figure out what would be the correct size for the load bearing LVL beam that would support the floor joists. Different manufacturers have span tables with different information. In my case pretty much the only LVL beam manufacturer available in my country is STEICO, and their documentation is a bit too technical for me.
Any tips guys? Or should I ditch the LVL beam idea and just put in much beefier floor joists that would go the entire width of the floor?
>that would go the entire width of the floor
*that would go the entire width of the floor without any support
Just a clarification
I work with a Builder's Supply store. They sell the material and help get you through the planning and permits. Else just put a quad in there and be done. Fill all the wall pockets with solid wood.
Basically take however much you actually need and double it for an engineer.
Live load = 40 lb/sqft
Dead load = 10 lb/sqft
Total load = 50 lb/sqft
Tributary width = 10.375 ft (half of each span bearing on the beam)
10.375 ft x 55 lb/sqft = 519 lb/ft uniform load on beam
I can only really size out the beam based the specs of the Weyerhaeuser "TrusJoist" LVL's I use in my area of the US. I know each manufacturer's version of LVL's have different span ratings, but I doubt they are hugely dissimilar. So if I just add maybe 15% to the load then size the beams based on that it should be pretty safe.
519 lb/ft x 1.15 = 597 lb/ft
So we're looking for an LVL beam that is rated to carry 600 lb/ft uniform total load over a span of 17' with a deflection of no more than L/360:
- two 14" LVL's
- three 11 7/8" LVL's
- four 11 1/4" LVL's
- five 9 1/2" LVL's
However if I were doing this I would just run full length joists I suggested earlier
as it will result in a continuous flat ceiling and floor above. If you do it with 2x6's and an LVL beam like in your sketch, that beam is either going to stick down below your ceiling or up through the floor above.