Installing Loft Beams

Before you cut and raise your rafters, install the loft floor beams. These tie the side walls together, while also letting you set up a loft floor on which to work later, while the rafters go up.

Although you could install ordinary joists to create the loft floor frame, nothing says “real cabin” like thick, exposed, solid wood beams. That’s why we used 6×8 beams on 24” centers for our cabin loft. I had them custom-sawn to the size and the 16-foot length required. It doesn’t even take significantly more wood by volume than 2x12s either.

Cut the loft beams to final length (timbers like this are often a few inches longer than specified length), then lift them up on your wall and position them on the marks you created earlier. To get the beams up, Robert and I hoisted one end of one beam onto the top of the wall as we stood on the cabin floor with the other end resting on the floor, too. Next, we climbed on step ladders while we lifted the other end of the beam up on the wall. Even when green and heavy, it wasn’t much work lifting these loft beams up by hand working together. Remember, loft beams flank the location of rafters you just marked.

Incorporating beams into stud frame construction isn’t standard practice, but it is a simple and effective way to add rustic charm to a structure. Just remember that the beam closest to the back wall requires an angled notch on each end, as explained earlier in the Interior Rafter Detail video. Cut this notch now, before anchoring this loft beam.

All loft beams are secured with two 12”-long spikes pounded into 1/4” diameter predrilled holes. As you pre-drill these holes, keep them 1 1/2” out from the outside face of the stud walls. This keeps the spikes well away from the ends of the beams that will be cut on a 45º angle later, after the rafters go up. Continue installation until all seven beams are up and spiked. Be sure to wear safety glasses as you pound these spikes in place. You have to hit the heads hard to drive in something this long, and it’s not unusual for bits of metal to break off the spike heads and fly. Years ago I had bit of spike head removed from my eye, and my eye protection lesson was learned for good. Let it be your lesson, too.