Floor Bent Over Joist

This length has a maximum safety capacity that is based on the width and material used to make the floor.

Floor bent over joist.

I am wanting to install real hardwood flooring over my wood sub floor. On the top side of the floor another fix it idea to lay down new hardwood over the existing floor. The floor above will be stiffest if you place the wall in the middle of the joists. Floors are specifically designed to support the weight of people and furniture in homes and buildings and part of the way they do this is with floor joists which are horizontal supporting beams that run beneath the floor a floor joist span is the length a floor joist goes across a room.

But it s usually best to run the sister joist over the entire span. The longer the distance a joist spans without support the more it will flex. By building a wall under joists you divide the span. 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.

It is interesting to note that the deflection of the subfloor and underlayment panels in figure 1 relative to the top of the joist is zero no deflection even though the panels are clearly bent over the joists as represented by two radii r and 1 44r. If you have improper holes and notches from alterations and running service lines this can be the source of weakened joists. I live in south east texas it gets hot here so a c runs a lot. What i have for a sub floor is 1 2 plywood then 15lb felt then 5 8 plywood.

When the sagging joists are level apply a generous bead of construction adhesive to the existing joist. If you build a wall to support joists be sure to place a stud directly and tightly under each joist. As an organic material wood joists are prone to deflection under load. There shouldn t be any cuts or penetrations in the middle third of the joist or at the bottom of the joist either.

If your floor joists have been cut improperly to install pipes wiring or hvac ducts this could be causing your floor to slope. A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too. 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. However the amount of bend or deflection allowed by most building codes typically joist length divided by 360 does not address the nature of lumber to creep creep in this sense means to nominally bend over a prolonged period of time.

When building a house or even a deck it is important to confirm you have the correct joist sizes spans and spacing before you get started. I also have 6 bat insulation on bottom being held up with chicken wire. But larger is not always better when builders are constructing a home or adding a room addition. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length.

Joist span and spacing is set by your local building code.