Construction Floor Framing Terminology

Lumber dimensions, nail dimensions, floor framing terminology

Nominal - 1 X 2

Actual - 3/4 X 1 1/2

Nominal - 1 X 3

Actual - 3/4 X 2 1/2

Nominal - 1 X 4

Actual - 3/4 X 3 1/2

Nominal - 1 X 6

Actual - 3/4 X 5 1/2

Nominal - 1 X 8

Actual - 3/4 X 7 1/4

Nominal - 1 X 10

Actual - 3/4 X 9 1/4

Nominal - 1 X 12

Actual - 3/4 X 11 1/4

Nominal - 2 X 2

Actual - 1 1/2 X 1 1/2

Nominal - 2 X 4

Actual - 1 1/2 X 3 1/2

Nominal - 2 X 6

Actual - 1 1/2 X 5 1/2

Nominal - 2 X 8

Actual - 1 1/2 X 7 1/4

Nominal - 2 X 10

Actual - 1 1/2 X 9 1/4

Nominal - 2 X 12

Actual - 1 1/2 X 11 1/4

Common nail - 2d

1 in

Common nail - 3d

1 1/4 in

Common nail - 4d

1 1/2 in

Common nail - 6d

2 in

Common nail - 8d

2 1/2 in

Common nail - 10d

3 in

Common nail - 12d

3 1/4 in

Common nail - 16d

3 1/2 in

Common nail - 20d

4 in

Coated nail - 6d

1 1/4 in

Coated nail - 8d

2 3/8 in

Coated nail - 10d

2 7/8 in

Coated nail - 12d

3 1/8 in

Coated nails - 16d

3 3/8 in

Mudsill

Wood framing (typically 2’’ x 8’’) that is bolted to top of foundation walls. In addition the floor joist system rests on this framing.

Sill Sealer

A product (Homasote, flexcell) that is placed between bottom of mudsill and top of foundation walls. It provides a moisture barrier so that the wood mudsill won’t rot or decay.

Post (lally column)

This is an adjustable steel column that supports the beam at intervals determined by the allowable span of the beam. The post sets on a 24’’ x 12’’ deep foundation. Adjustable screw jack is at bottom and poured into floor.

J-bolt

Typically 1/2 ‘‘ diameter 18’ long anchor bolt installed in mortar at top of foundation walls. This is how the wood mudsill fastens to top of foundation walls. Bolts installed at 16’ intervals around perimeter of foundation and span no more than 12’ off any corner.

Beam (Girder) - wood

-Build up -Glulam -LVL

Beam (Girder) - steel

- wide flange (I Beam)

- It supports the floor joist at lap joints or at mid points of span as dictated by the allowable span distance of the floor joist.

Glulam Beam

A beam that consists of solid dimension lumber that is stacked and glued together.

LVL Beam

Laminated veneer lumber that is glued together.

Floor joist

Horizontal framing that span your foundation opening. The subfloor is glued and nailed to them. They are placed at a 16’’ O.C. layout.

Header joist

A component of the rim joist. The ends of all the floor joist nail to this framing member which keeps floor joist from tipping.

Rim joist

Outer band of joist that are installed around the perimeter of the foundation.

End joist

A component of the rim joist. These run parallel to the floor joist and tie in the header joist.

Joist Hanger

Metal bracket that joists rest in to provide support and help carry load.

Subfloor

4’ x 8’ sheets of tongue and groove either plywood or O.S.B 3/4 thick serves at the base for finish floor materials. Placed on top of joist system. Glued with subfloor adhesive and nail with 8d ring shank nails.

Solid Bridging (blocking)

Solid/dimension lumber installed in joist cavities at ends of foundation they help tie in end joist over beams in order to keep lap joint together.

Cross Bridging

Typically 1 × 3 pine installed at 8’ intervals into joist cavities provides strength to floor by not allowing flex or bow of joists to occur.

Allowable span for Beam

The distance a beam can span unsupported by a post below.

Allowable span for Floor Joist

The distance a joist can span unsupported by a beam.

Deadload (Floor)

All materials used to construct floor 10lbs P.S.F

Liveload (Floor)

People, appliances, etc… that will be placed on the floor 40 P.S.F