Can I use a wood top plate on top of a steel track to build a roof-bearing steel frame?

Question

I am building a room within my garage using double studs, double track, steel framing. The outer dimensions for this room are 23' l x 16' 6" w x 10' h, and will share no common walls or ceiling with the garage space. The garage floor is 6" thick concrete.

Most steel construction calls for attaching the tracks to existing floor / ceiling joists, and then place the studs in between the two tracks. This will not work for my application, as I have no ceiling joists to attach to (so the top track will be flimsy).

To solve this problem, I would like to use a wood top plate on top of a steel track, and build a flat roof on top of the wooden top plate. (Similar to Detail No. W1 (p60) from the HUD: Hybrid Wood and Steel Details-Builder's Guide document.) The "Data" on page 61 of the guide lead me to believe this approach is possible.

My concern is that I have not found any examples of this kind of construction from searching the internet.

Questions:

• Does adding a wood top plate on top of the steel top track provide enough weight to stabilize the wall?

• Are there any resources showing a build detail of this kind of construction?

Answer 1

We design from the top down and build from the bottom up. I’ve learned that staying with “standard building techniques” in both the design and construction phases will save time and money.

We design custom homes and when we use a product that’s never been shipped west of the Mississippi, then we’ll pay extra for that particular product and pay extra for the labor to prep and install, because the local contractors are not familiar with that product.

Likewise, if we design a 12’ diameter curved wall in the house, we’d better have a good reason, because that wall will cost extra.

Likewise, if you design a composite wall construction detail, you’d better have a good reason because you’re going to pay extra.

Standard building practices tend to use either steel or wood, but not combined because they are not familiar to 1) codes review technicians, 2) building inspectors, 3) sub-contractors who will need to adjust their products to fit the new technique, and 4) General Contractors who will need to coordinate scheduling, miscellaneous materials to finish installations, etc.

There are some issues with your assumptions. Steel construction does NOT make rooms more or less soundproof. (Staggered stud construction, double wall construction, types of materials used on and in the wall, etc. all help with sound control.) Steel construction (non-combustible construction) is for better fire resistance, not better soundproofing.

Summary: There’s a reason that you’re not finding “typical” construction “details” (as you call it) because it’s not done often or frequently. Mixing construction systems will increase costs and may eliminate some contractors from participating.