If we use the same joist total deflection will be 1 50 1 25 0 25.
Live and total load deflection for title floor.
The subfloor areas over which stone tile is to be applied must be designed to have a deflection not exceeding l 720 of the span.
When the dead load is applied to a cambered beam the curvature is removed and beam becomes level.
Figure 2 live loads and deflection limits are set by code.
Design substrate for total load deflection not exceeding l 360 as measured between control or expansion joints.
These limits are based on live loads and activities experienced in specific rooms of a house.
The table of contents indicates.
Examples of code prescribed deflection limits and live load values are.
Bedrooms and habitable attic floors l 360 30 psf.
However the limit on total deflection is span 720 resulting in the need for total deflection to be only 0 50 half of the 1 00 value for span 360.
Living room floors l 360 40 psf.
Step 2 span table.
Therefore the live load deflection is of concern in the completed structure.
Tile industry associations recommend special total load deflection limits the following tables list the components and weights of typical floor systems along with the deflection limits that apply.
Allowable deflection for this floor joist is approxi mately 1 2 in.
Camber is a curvature in the opposite direction of the dead load deflection curve.
Typical deflection limits referenced in code books are l 360 l 240 or l 180.
Now consider the same floor joist supporting stone tile flooring such that floor dead load is now 20 psf.
Span rafter with a 4 12 slope and no ceiling attached has an allowable deflection of l 180 which is twice the deflection allowed for floor joists.
These tables are from the icc international residential code.
The amount of flex depends on the magnitude of the load applied span of the member and stiffness of the member.
3 8 2 cast in place concrete floors.
This sets an allowable first floor live load of 40 psf a dead load of 10 psf and a deflection of l 360.
The tile council of america recommends that deflection be limited to l 360 l span length in inches under total load for ceramic tile.
Typically for better performing floors minimal defection is desired.
Calculating dead loads the prescriptive tables of the irc detailing continu.
With an evenly distributed live load of 30 psf which the tables show the floor is able to support the total weight on the floor would be about 3 360 pounds.
Increasing the total weight on the floor to 4 480 pounds however results in a live load of 40 psf which is beyond the floor s load capacity.
