dimensional lumber length

[John Dirks Jr]

The house pictured below was built in '61 and the left half was on a below grade basement and the right half was on a crawl space. It had steel I-beams spanning the center of each foundation section supported by steel columns. No biggie right?

Well, when the client asked me about removing walls to change floor plan in the basement I took a close look at the floor structure to see if her ideas would present any challenges. What I found was unusual. The floor joists were 2x8 @ 16" OC and spanned the entire distance from sill to sill. Yep, 25' long dimensional 2x8 supported by the I-beam in the middle.

Being a part time inspector, I don't see as many houses as most of you. So, you may not find this too unusual. This find yesterday was a first for me.

Is this unusual or do I not get around enough?

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[John Kogel]

Could they be 24 footers, with a band joist nailed across at each end adding another 3 inches? 24' is a standard length. Then with 2 X 4 walls, the interior dimension would be 3-4" short of 24'.

Lumber from a local mill in 1961, could have been a custom order. But the max span for 2 X 8 joists is 12', and that is what we would expect to see. So yes, 25' seems unusual to me too.

In this area, lumber cut in 1961 is old-growth Douglas fir, tight grain and hard as nails. A bit of an overspan shouldn't bother anybody. Maybe a concern for pine or spruce.

[Mike Lamb]

It's more common in older buildings around here. My house, 1962, has 24' 2x10. The joists are always spliced at the beam these days.

[Jim Katen]

It's unusual. 24' long lumber has been available as long as I can remember, but it's a special order item and it usually got used for things like hip & valley rafters.

[John Dirks Jr]

I only had a 16' tape and was hasty in my measurement. They are probably 24' rather than 25' like I initially stated.

I've never seen it before.

[Marc]

Doesn't seem like an over-span for 60's lumber. The floor joist span tables from the 06' IRC shows most species good for more than 12' 6", even at 20 lb/SF dead load.

Marc

[Steven Hockstein]

Sometimes there are weird forces (i.e. uplift) that can occur with continuous floor joists that may result in some noticable humps and sags. It depends if the loading from above is aligned with the basement supports.

[gtblum]

It's unusual. 24' long lumber has been available as long as I can remember, but it's a special order item and it usually got used for things like hip & valley rafters.

I think the same might be the case with anything over 16' these days. I used to see 20' lumber in the yards but, not anymore.

[Mike Lamb]

I bought some long 2x6 15 yrs ago to cross brace a garage. 22' I think. I thought it had cost $40 for one piece but I must be mistaken. I called my local yard and a 2x8x24 is only $30. Not bad.

My local lumber yard (Fox Lumber) carries 2X's in stock up to 2x12x26.

http://www.foxhomecenter.com/construction_grade.htm

[Erby]

Did you take a look up in the attic to help determine which first floor walls are load bearing. Support, in the floor structure, under the load bearing walls is also important. My guess is it would just be one load bearing wall down the middle of the first floor but oughta check anyway to make sure.