Download PDF version (1257.3k) Log In or Register to view the full article as a PDF document.

Launch Slideshow

A New Interior for an Antique House

Finding and correcting structural issues

A New Interior for an Antique House

Finding and correcting structural issues

  • http://www.jlconline.com/Images/1819660884_1009_JLC_New%20Interior_00a_tcm96-1179426.jpg

    true

    600

    When he bid the job, the author knew that fulfilling the architect's vision for a sleek, modern interior in this 150-year-old timberframe house would be riddled with challenges. Nothing was plumb, level, or square; and there would be very little interior trim camouflage defects.

  • http://www.jlconline.com/Images/817416786_1009_JLC_New%20Interior_01a_tcm96-1179427.jpg

    true

    600

    The exterior of the 150-year-old timber-frame building was in reasonable condition.

  • http://www.jlconline.com/Images/1297602262_1009_JLC_New%20Interior_02a_tcm96-1179430.jpg

    true

    600

    One of the first orders of business was to provide a center bearing wall in the basement. After cutting through the thin slab, the author's crew dug a trench the length of the basement for a new reinforced concrete footing.

  • http://www.jlconline.com/Images/1791801491_1009_JLC_New%20Interior_02b_tcm96-1179431.jpg

    true

    600

    To accommodate the bearing walls for a stairway, the 12-inch-deep by 24-inch-wide footing widens to 5 feet at one end of the basement.

  • http://www.jlconline.com/Images/1096316755_1009_JLC_New%20Interior_03a_tcm96-1179432.jpg

    true

    600

    The floor framing was removed in sections and interior bracing installed to stabilize the walls; tall posts supported the floor system above.

  • http://www.jlconline.com/Images/1658300130_1009_JLC_New%20Interior_03b_tcm96-1179433.jpg

    true

    600

    Many of the oak sills supporting the exterior wall framing had rotted.

  • http://www.jlconline.com/Images/962815394_1009_JLC_New%20Interior_03c_tcm96-1179434.jpg

    true

    600

    Instead of trying to fasten new floor joists to the rotten sills, the crew placed new 2x4 pressure-treated sills on the inner portion of the wide foundation, then set a double-LVL rim joist on top to catch the ends of the new I-joists.

  • http://www.jlconline.com/Images/686486695_1009_JLC_New%20Interior_03d_tcm96-1179435.jpg

    true

    600

    This approach allowed reframing of the floors to proceed in sections.

  • http://www.jlconline.com/Images/1275575039_1009_JLC_New%20Interior_05a_tcm96-1179528.jpg

    true

    600

    Diagonal braces prevented the exterior walls from spreading as the floors were reframed, a section at a time.

  • http://www.jlconline.com/Images/2121146159_1009_JLC_New%20Interior_05b_tcm96-1179529.jpg

    true

    600

    Carpenters removed the bottom clapboard courses and removed the rotted sills from the exterior, replacing them with built-up pressure-treated 2x8s. Then they fastened the new LVL rimboards to the built-up sills from the interior using GRK screws. (See the drawing "Sill Retrofit " on page 4 of the PDF for more details.

When I was invited to bid on the complete renovation of a 150-year-old house, I knew the project would pose some major challenges. While the interior needed all-new plumbing, electric, and hvac systems, the real trick would be executing the architect’s design: to create a contemporary interior with an open floor plan inside the traditional exterior. Nothing was plumb, level, or square in the old structure, which would make layout and alignment of the aesthetic elements very difficult. In a traditional interior, you can scribe the trim and fudge reveals to hide the defects; in this case, there would be very little trim to work with. The framing would have to be dead on.

Structural Issues

Originally built in the mid-1800s as a boarding school for girls, the house had been converted some 50 or so years later into a private residence (see slideshow). When my clients purchased the building a couple of years ago, it was in the midst of an extensive but incomplete renovation. Like many old houses, this one had serious structural problems.

The timber-frame building had three oak bents with 8-by-8-inch vertical posts, 8-by-12-inch horizontal beams, and 3-3/4-by-3-3/4-inch studs roughly 16 inches on-center in the exterior walls. The floor framing was a mixed bag, especially the first-floor deck, which had a hodgepodge of 2x8 and 2x10 joists feeding into various girders that had been propped up over the years with wood posts. Also, the tops of the walls had bowed out from the weight of the roof and were as much as 2-1/2 inches out of plumb over 9 feet in some areas.

The structural engineer’s remedial plan included the addition of several LVLs to reinforce the original beams, new posts in the exterior walls to carry the new point loads, a new center bearing wall in the basement to support bearing walls above, and five 1-inch-diameter steel rods with turnbuckles to tie the building together and prevent the walls from spreading further.

As we demolished the interior finishes and exposed the existing framing, we found that in some places the outside walls had spread so much that the floor joist tenons had slipped out of their mortises. In the second-floor framing, we discovered a 44-foot-long 8x12 oak beam spanning the building from front to back. As part of the last renovation, the ceiling in this area had been furred down flat with metal framing and drywalled, so the engineer didn’t know about the beam — which had a 6-inch sag in the center.

Given these serious problems, I wondered whether all the new structural shoring would mesh with the new contemporary interior design, or whether it might be better to remove all the existing floor framing and install new I-joist floor framing throughout. This would give us level, flat floors to work from and make the rest of the finish work much easier, and would also eliminate the five 1-inch steel rods from the design. As long as the cost wasn’t prohibitive, the engineer liked my idea, so I met with the homeowners and walked them through both scenarios. The new engineered floor systems would add $6,000 to our $11,000 estimate for the originally proposed structural work — a cost they decided they were willing to live with.