Good notes

1. Types of Upper Floors:
Based on materials used for
construction:
Depending upon the materials used for construction and upon the
arrangement of beams, girders etc. for supporting the flooring upper
floors are classified as:
1. R.C.C. Floors
2. Steel joist and stone or precast floors
3. Jack Arch floors (brick and Girder Cement Concrete Floor)
4. Filler Joists Floors
5. Precast Concrete Floors
6. Timber Floors

2. 6. Timber floors
• Found in earlier construction
• Costly( Except at those locations where local timber is cheaply
available)
• Fire Poor resistance
• Highly vulnerable to termite
• Light in weight
• Sound insulation
Timber floors are basically of three types:
A. Single Joist Timber Floors
B. Double Joist Timber floors
C. Framed or Triple Joist timber Floors

3. A. Single Joist Timber Floors
• Simple type of timber floor
• Used for short span mainly for residential bldgs.
• Span up to 4 mt.
• For lighter load

4. • The end of the joists are nailed, cogged or notched to the wall plates.
• If the joists of adjacent room run in the same direction, they may be
overlapped and nailed to each other.
• Planking consists of wooden boards of 4 cm thick and 10 to 15 cm
width, which are fixed to the bridging joists.
Single Joist Timber Floors

6. B. Double Joist Floor
• Stronger Floors
• Used for span between 3.5 to 7.5

7. • The bridging joist are supported on intermediate wooden support
known as binders
• Loads of bridging joist are transferred to the binders and through them
to the end walls
• Because of intermediate supports the bridging joist are of smaller
sections
• Joist are spaced at 30 cm centres
Double joist floor

8. • Spacing of binders is kept at 2 to 3.5.
• Binders rest on stone or wooden templates.
• To reduce the depth of floors bridging joist are cogged to the binders.
• Ends of bridging girders are cut and joint with help of fillers provided
along the two sides of walls.
Double Joist Floor

12. C. Triple or framed joist floor
• Floor is suitable for spans greater then 7.5 mt.
• Intermediate support known as girders are provided for the
binders
• Elements for flooring
1. Floorboards
2. Bridging joist
3. Binders
4. Girders

13. Triple or framed joist floor

14. Triple or framed joist floor
• Bridging joist supports the floorboards
• The binders are staggered and connected to girders to increase the
rigidity of the floor to decrease the overall depth of floors
• Sometimes girders are replaced by rolled steel joists

19. Single Joist Timber
Floor
Double Joist Timber
Floor
Triple Joist Timber
Floor
1 Simple type of timber
floor
Stronger Floors Very Strong Floor
2 Span up to 4 meters Used for span between 3.5
to 7.5 meters
suitable for spans greater
then 7.5 meters.
3 Element
1. Floorboards
2. Bridging joist
Elements
1. Floorboards
2. Bridging joist
3. Binders
Elements
1. Floorboards
2. Bridging joist
3. Binders
4. Girders
Comparison of all three Timber floors: