This is the distance between joist centres.
1st floor ceiling joist depth.
The bulk of the floor s thickness comes from the joists which are the horizontal beams that carry the floor s weight.
Joists in home construction are usually made with 2 by 10 or 2 by 12 lumber.
But larger is not always better when builders are constructing a home or adding a room addition.
If you re figuring the total height of a house the thickness of the floor will depend mostly on the size of the joists.
In many countries the fabrication and installation of all framing members including joists must meet building code standards.
Joists must exhibit the strength to support the anticipated load over a long period of time.
The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example.
The weight of the timber floor itself consists of the timber joists the plasterboard ceiling underneath it except for suspended timber ground floors the floorboards and the nails or screws used to fix both of the aforementioned coverings.
If you simply set the new joists on the old they probably won t mate well and any slope in the old floor will translate through to the new.
I d suggest you first run a continuous 1 by or 2 by plate across the ends of the existing joists to provide a stable base for the new joists.
To change it click on another option.
Standard floor thickness however is substantial in order to provide the strength necessary for bearing the weight of the walls the ceiling and the roof.
Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor.
However for practical purposes the self builder will still find the span tables in the old archived approved documents from 1992 to be useful in determining sizes for floor ceiling and roof joists binders rafters and purlins.
Ceiling joists are usually installed either 16 or 24 inches on center which means roughly 16 or 24 inches apart.
Enter a span for the joist.
Select the on center spacing for the joists.
Usually 400 450 or 600mm but any value can be used up to 610mm max usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size.
Considering the cross section of a typical joist the overall depth of the joist is critical in establishing a safe and stable floor or ceiling system.
Most lay outs are on 16 so the field is pre selected.
There is extremely little difference between the old span tables and the new ones.
This is how far apart they will be.
Once you ve located the first one the others are easier to find.
