Month: November 2011

I’ve been working on the first floor plan. Getting a floor plan that we like is the first step toward getting our permits, estimating what all this will cost, and even determining how we do the structural repair in the basement. After the post I made about floor joists, we decided to come up with a floor plan that keeps the existing load bearing wall in place, but replaces the full stud wall with long span beams to support the existing 2×6 floor joists. We’ll reinforce those either by sistering or adding cross bracing. Because of this, we need a floor plan that keeps the span lengths short enough to use LVL headers or wooden I-Joists. Every four feet in span increase cuts the load bearing ability in half, so I came up with a floor plan that keeps the spans less than sixteen feet.

The next design constraint was keeping the existing wet wall, where the plumbing lines, drains, and vents are. This is important for a couple of reasons. One, keeping the plumbing consolidated will lower costs and simplify the project. More importantly, though, is the fact that we’re living on the second floor, so the wet wall needs to stay where it is so that we can keep flushing the toilet, taking showers, and washing dishes while the first floor remodel is ongoing.

The house is very narrow, with an interior width of only twenty feet. The load bearing wall runs along the length, but instead of being in the center it’s about eight feet from one wall. Right now the rooms on the small side of that wall are only 7 1/2 feet wide, which is pretty small by today’s standards. In order to work around that we’ll wind up having a beam sticking down from the ceiling, but since the ceilings are ten feet high, it shouldn’t be too bad.

Sarah loves to cook, and most entertaining these days winds up in the kitchen. Because of that we decided to make the kitchen big, and to forgo a formal dining room that would probably only be used a few times a year. Instead the plan calls for a big, counter-height table in the kitchen that serves as both work space and dining table. While meals are being prepared or just during parties, people can congregate in the kitchen with plenty of room to move around and sit without getting in the way of the cooking. We’re going to splurge on the stove. Instead of getting a cooktop or a range with a double wall oven, we’re going to get a big 48″ range with griddle, grill, and two ovens. That will be the centerpiece of the kitchen with the rest of the prep area to either side and a big buffet counter on the far side of the table.

We also wanted to fit an office onto the first floor, partly because we spend a lot of time by the computers and partly because we’ll need a bedroom to sleep in while we’re redoing the second floor. The plan calls for a powder room instead of a full bath. That was a tricky point, because as I said, we’re going to be redoing the second floor once this is all finished. Without a full bath on the first floor we’ll need to redo the second floor in stages, keeping the existing bathroom until we’ve finished the master bathroom. Finally, there’s a small den at the back of the house to connect the entertaining space to the screened deck we’ll eventually be building on the back.

The plan is still subject to further revision, especially once we start going through permitting and have to get all of this approved. There may be structural and code requirements I haven’t accounted for. However, this is the direction we’re looking at.

One of the challenges I’ve been mulling over in my brain for quite some time is how we’ll tackle the floor joists. The good news is that we’re not there yet, so we have time to figure it out. First, let me explain a bit how the floors are built and why I’m thinking about it.

Balloon Framing

The house is balloon construction. If you don’t know what that is, check out the link for details, but in short we have studs running the entire height of the house. A ribbon is notched into the inside perimeter of the studs at the height of the floor joists, which then rest on top of it and are nailed to the studs. The floor joists for the first floor are 2x10s, so they’re decently strong and the floor is nice and stable. The second floor, on the other hand, has 2x6s. Being so much smaller means two things: the floor has a lot of bounce (known in engineering terms as deflection) and it can’t span as far. Both of those are issues because we want to make the floor plan on the first floor more open and we want to have stable floors upstairs, especially since we’re planning a second floor laundry.

So what to do about it? Well there are a few options. The simplest option is to sister additional 2×6 joists to the existing ones. That means we can’t increase any spans, though, so we’d need to define a floor plans that is either more enclosed or has support beams below the joists to carry the load. I’m not a fan of support beams visually, but we could integrate them into a coffered ceiling or archways between rooms.

A more involved option is to add new joists that are either I Joists or Open Web Trusses. These could be installed throughout the floor or only in areas with larger spans. They would lower the ceiling by at least six inches. The I Joists in particular are capable of spanning the full width of the house with minimal deflection. Installing these isn’t a simple matter, though. For one, we’d have to do a lot of load calculations to ensure the structure was stable. More importantly, we’d have to cut out the walls that were still holding up the existing floor joists in order to fit the new, taller joists in. We’d also have to build new framing structure into the outside walls to carry the increased load to the foundation. All of this gets very complicated and guarantees we have to bring in a structural engineer.

This is pushing me back toward the simpler option, but there’s an added wrinkle: HVAC. Even if we have radiant floor heating, we still need ducts for air conditioning or even just air circulation. We want to have a whole house air filter, especially once we’ve sealed all the walls, windows, and doors up tight. Without forced air heat, there still needs to be a system to bring in fresh air from outside or at least filter the indoor air. How we run the duct work depends on the system we get. One of the reasons we’re looking at high velocity forced air is that it uses smaller diameter ducts, but even so we need a main trunk, plus we can’t exactly cut big holes through the 2x6s when they’re already so small.

The plan is to run the HVAC from above and below, meaning the first floor ducts will be in the basement and the second floor ducts will be in the attic. Unfortunately, with the ceiling in the basement being so low I can’t help but think this isn’t the best plan. We hope to lower the basement floor to gain some inches, but even so it won’t be all that high. I’m wondering if some creative ceiling designs might solve these problems. If we can use a combination of coffers in the living room and strategically placed bulkheads in the kitchen and dining room, we may be able to work out a solution that lets us keep the joist height as it is and still reinforce the floor.