## What is the maximum span for a 2×8 ceiling joist?

A rule of thumb is 1.5 times a joist’s depth but in feet when spaced at 16” centers. In general, a 2×8 will span 1.5 x 8, so 12-feet.

## What is the maximum span for a 2×6 floor joist?

2-grade 2×6 joists can span up to 10 feet 9 inches from beam to beam when spaced the standard 16 inches apart with a maximum live load of 30 inches per square foot. In comparison, No. -1 grade lumber can span slightly further to 10 feet 11 inches under the same parameters.

## What size joists should I use?

Commonly used joist sizes are 2-by-6, 2-by-8 and 2-by-10. For example, when you space joists 16″ apart — which is standard for residential decks — a deck spanning 9 1/2′ would require 2-by-6 joists, a 13′ deck would need 2-by-8 joists and a 16′ deck calls for 2-by-10 joists.

## How do you determine the number of joists required?

For example, assume the clear span is 15 feet 6 inches. Round up to 16 and divide this span by 2, giving you 8. Next, add 2 to get the required joist depth. In this example, 8 + 2 = 10, so a 2×12 floor joist will be required (it’s important to use the actual lumber dimensions, not the nominal dimensions).

## Can I use 2×8 for deck joists?

2×8 for joists will be fine, with 16″ OC. Should use 2×10 for beams but 2×8 will be fine as well. If you are worried you can triple the 2×8 for the beams but double will be sufficient. You should put the beams at 7 and 14 feet out from the house, with the piers you should do 3 per beam with spacing of 1, 7, 13.

## What will a 2×10 span?

How Far Can a 2×10 Beam or Header Span? A 2×10 beam – made up of two 2x10s nailed together – can span up to 11′ without support beneath a deck that is 4′ wide. For a more normal-sized deck, the same beam can span 8′, supporting a deck that is 8′ wide.

## Are 2×6 OK for floor joists?

2x6s may be used for floor joists, ceiling joists, or rafters and have differing spans for the same grades and species. Loads are divided into live or snow loads and dead load considerations. A plank used for a floor joist commonly has different load factors than a ceiling joist or rafter.

## Are 2×6 strong enough for deck joists?

You can use 2×6 as deck joists if the deck is low enough to the ground as not to require guard railing. When using S-P-F 2×6 deck joists, the span must not be greater than 9’0″ (2.73m) with joists at 16″ o.c. (400mm), and 9’10” (3.01m)with spacing at 12″ (300mm).

## Should deck joists be 2×6 or 2×8?

For upper-level decks, 2×10 is recommended as the minimum size to use for strong guard post connections. 2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards.

## How many joists is 16 feet?

Nine joists will be needed for the 16-foot width.

## How many joists is 12 feet?

A 12-foot long deck with joists 16 inches on center will require 10 joists.

## What size joist do I need for a 12 foot span?

Thus you will need a 2×6 (2-by-6) size of floor joists for 12 foot span at standard 12 inches spaced.

## How long can joists be without support?

The maximum span for a floor joist that needs to support a 40 psf live load would be just over 23′.

## How far can 2×8 span 12?

Max. Live Load 30 lbs/ft2 (1436 N/m2)

Maximum Span (ft – in)
Nominal Size (inches) Joist Spacing Center to Center (inches) Lumber Grade
2 x 10 24 15′ – 0″
2 x 12 12 24′ – 8″
16 21′ – 4″

## How far can a 2×12 span for floor joist?

A 2×12 (2-by-12) floor joists can span up to 23 feet 3 inches, 2×10 (2-by-10) up to 19 feet 1 inches, 2×8 (2-by-8) up to 15 feet & 2×6 (2-by-6) up to 11 feet 4 inches at 16″ spaced by using southern yellow pine graded as #1 when live load of 30 lbs/ft^2 & dead load of 10 lbs/ ft^2.

## How big of a beam do I need to span 20 feet?

For a 20-foot spans, the wood beam has to be at least 16 inches in depth and 8″ in width (4-2×16) used for residential building or projects.

## How big of a beam do I need to span 16 feet?

For a 16 foot span, you will need atleast 3-2×14 or 6×14 size of wood beam. Thus, a 3 nailed 2×14 or 3-2×14 or 6×14 wood beam can allow to span 16 feet. For a 16-foot spans, the wood beam has to be at least 14 inches in depth and 6″ in width (3-2×14) used for residential building, wood frame structure or projects.

## Do floor joists have to sit on a beam?

Floor joists spread the loads bearing from above, and must be framed adequately to complete the load paths. Ideally, if a load-bearing wall runs parallel to floor joists, then it should sit directly over a beam or a joist supported by a load-bearing wall below.

## Do walls sit on joists?

All exterior walls are bearing walls. They support the roof at the ends of the joists. The interior bearing walls support the floors above and the attic weight. They support the joists at midpoint.

## Should I use treated lumber for floor joists?

Generally, building codes require pressure-treated or naturally durable wood for the following applications: Joists or the bottom of structural floors without joists that are within 18″ of exposed soil. Beams or girders closer than 12″ to exposed soil.