Plywood Orientation On Floor Joists

If this is correct you are running into the fact that each piece of plywood is creating a bridge effect.

Plywood orientation on floor joists. While personal preference is a factor the direction in which you run hardwood flooring boards is governed by visual and structural guidelines. Regarding my 3 8 exterior grade plywood which i am almost ready to apply for a floating wood floor as my theory went since the grain seems to run lengthwise along the 8 length laying the panels parallel to the joists would allow the cross grain 4 length to span between perpendicular to the joists where the added stiffness is desired. What type of plywood should i use cdx. The house is l shaped due to a renovation done in the 90 s.

Ashton avegno an engineer from new orleans louisiana answers this question and explains the orientation of plywood depends on its location and use. Potential problems exist if the framer locates the plywood joint directly over the joint between the second floor plate and the band joist. If you were to run your plywood the opposite direction then the board would only connect 3 joists. Chalk lines are pulled all the way across all the joist tops at the 4 foot marks so we can check our accuracy with each sheet of plywood being attached to the joists.

The correct direction for laying hardwood floors. Some experts suggest that 15 32 inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less but slightly thicker 3 4 inch plywood should be used for joists spaced further apart. On the tops of the floor joists we measure and mark every 4 feet this will be the plywood seams. Meaning that every four feet a new bridge occours the joists are not acting as one floor acheived by over lapping plywood over 7 joists the correct way was to run ply wood across joists.

Apa performance rated i joists pris are manufactured in accordance with pri 400 performance standard for apa ews i joists form x720 this performance standard provides an easy to use table of allowable spans for applications in residential floor construction allowing designers and builders to select and use i joists from various member manufacturers using just one set of span. Laying your first piece in the outside corner of the floor you want the long dimension of the plywood to lay across six joists with the final edge ending up in the center of the 6th joist. The recommended thickness of the plywood subfloor is governed by the spacing of the joists. The front of the house short leg of the l has the joists running e w and the back of the house long leg of the l has the joists running n s with the subfloor running perpendicular to the joists in each leg.