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Q: Home construction and structural specifications of load bearing headers ( Answered,   0 Comments )
Subject: Home construction and structural specifications of load bearing headers
Category: Miscellaneous
Asked by: joeb4-ga
List Price: $15.00
Posted: 21 Dec 2002 11:17 PST
Expires: 20 Jan 2003 11:17 PST
Question ID: 132199
I have a an 8' span that has a 4"x6"x8' header in place with (4) 4x4
posts supporting the header; two posts at the end and two in the
middle.  I want to put an 8'x8' door unit in this space but would have
to remove the 2 middle posts thus leaving the header supported at the
ends only.  I want to know if the header with the two midle posts
removed is sufficient for carrying the existing load of the wall.
Subject: Re: Home construction and structural specifications of load bearing headers
Answered By: hlabadie-ga on 22 Dec 2002 14:31 PST
Based on the tables for double 2x lumber obtained from:

Canadian Wood Council:

(Select Header from the first menu.)

(Watch the URL wrap.)

Ground floor building:

One floor, ceiling, attic, and roof building:

Two floors, ceilings, attic, and roof building:

and the load bearing capacities of sawn 4x timbers it would seem
inadvisable to remove the two middle posts.

The maximum loads per lineal foot that can be borne by a 4x6x8 of
various species are found in the table here:

Western Wood Products Association, Technical Note 6, Design Load
Tables for Solid-Sawn Lumber Beams and Headers (869K download):

The above are for new construction. You must also consider that age
and the condition of the timber (prolonged tension, drying, rot,
insect damage, etc.) may affect the bearing capacity of the header.

In addition to the possibility of the failure of the header, you must
also consider that the load formerly shared by four posts will be
divided between the two remaining end posts. This load no longer will
be evenly distributed through the foundation.

The load capacities of posts can be found in these tables:

Western Wood Products Association, Technical Note 9, Design Load
Tables for Wood Columns (Posts):

Software that will help to compute loads and spans:

Western Wood Products Association, Technical Note 8, Timber
Engineering Software:

Other resources:

Western Wood Products Association, Western Lumber SPAN TABLES for
Floor and Ceiling Joists and Roof Rafters:

American Wood Council:


Tutorial on calculating spans:

Sources for printed tables and manuals:

You might wish to consider installing a steel header and columns and
reinforcing the foundation.

Search parameters:

Wood frame construction

Follow the links from the American Wood Council site.

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