Removing a wall underneath joists that are already attached to beam in attic

Question

I want to remove a wall in a finished part of my house that used to be a garage. I went into the attic to see if the wall is load bearing and I discovered that the joists above the wall in question are already attached to a beam that runs end to end to two other walls. In other words I believe the wall I want to remove is not load bearing due to the fact that this beam exists and appears to be part of the original construction. The joists are 2x6 and the beam is 2x8s doubled up the joists are not hung by joist hangers just simply nailed into the beam.

The house was built in 1961 and I believe this was the common method used to attach joists. I am unsure of the species or grade of lumber used for the joists or beam and I understand this affects span distance. The beam isn’t quite centered in the house and it doesn’t run full length of the house. Looking directly at the beam the joists hung to the right span 11’6” from exterior wall to beam with no wall supporting them. The joists to the left span 13’1” from exterior wall to the beam, with the wall in question located directly under joists about 4’ to the left of the beam.

I know I can attach a beam to replace wall but my question is, is this needed since there is already a beam in the attic? Hopefully this makes sense I have pictures of everything and can provide other measurements and information if needed. I have not been into the crawl space to see if there are supports under the wall I want to remove. Also I noticed that were the joists meet the beam there is some seperation at the top of the joists from the beam, however they seem to be flush at the bottom of the joist. I understand this could be from settling or?

It’s worth mentioning this house was moved from its original loacation about 40 min away to a new location in one piece and set on a new foundation in 2005. I would like some advice and possibly a discussion about my plans for this project and ways to reinforce the joists themselves as there are no joist hangers or collar ties.

Thanks for anything you can contribute.

Answer 1

Often we’ll design beams into our buildings for “future” use. Your house may have one of these, but before you remove the wall and rely on the beam, you’ll need to investigate: 1) actual loads on the joists, 2) any independent loads on beam, 3) size of support posts at each end of beam, 4) size of “new” footing under each support post at each end of beam.

1) If your roof joists are 2x6’s spanning 11’ and 13’, I’ll assume you have little or no snow load. Therefore, the minimum roof load would be about 40 lbs. per square foot on the 2x6’s, which translates to 480 lbs. per square foot on the beam. Therefore, 2 - 2x8’s maximum span is about 8’, depending on the species and grade of the 2x8’s. Or, if you increase the beam to 3 - 2x8’s then the allowable span would be about 11’.

2) Before you determine the maximum allowed opening, you’ll need to verify there are no other loads, like a roof beam resting on the beam.

3) The beam will need to be “fully” supported at each end. That means a minimum of 2 - 2x studs (or a 4x4 post) will be required at each end.

4) If the original location had designed the beam, they probably designed an adequate footing under each end to transfer the load to the soil. However, I doubt they knew about the beam when they moved the house and therefore there isn’t a footing under each post.

Moving a house and placing it on a new foundation requires a Building Permit. Maybe you can contact your local Building Codes Department and look at the submitted plans.

Answer 2

If you look at Table 13 in this document

http://www.southernpine.com/app/uploads/SS_13-14L.pdf

you'll see that there's no way that doubled 2x8 is a girder beam. You don't mention the length of the doubled 2x8's but the table would tell you what to use for a beam.

My guess is there was originally a load bearing wall directly below the doubled 2x8's, or maybe posts.

Toenailing joists into the rim joist / band joist was normal construction in the 1960s, joist hangers came later. It was also common to overlap the joists over a load bearing wall or beam.