Building a hybrid home - that is, one with a combination of timber and conventional framing - is easier than you think.
Published by Timber Home Living, August/September 2005
Photos by Rich Frutchey
We all want architectural drama in our homes, but we're never quite sure how to achieve it. If you're adding timber elements, you're more than half way there. Indeed, many folks have discovered that they can marry the timeless beauty of timber and the more affordable option of conventional framing.
Yes, this type of home is all the rage - and it's typically called a hybrid.
We asked Jeff Davis, co-founder and president of Davis Frame Co. in Claremont, New Hampshire, to address the questions we hear most often about building this type of home.
Q: When does it make the most sense to build a hybrid? Is it a great way to save money?
A: The decision to build a hybrid home is based on aesthetic and/or cost consideration. Regarding aesthetics, most people don't want every room in the house to have cathedral ceilings, which timber framing usually creates. By using conventional roof trusses and an insulated flat ceiling, you can save money and still achieve a wonderful look. In main-level bedroom wings or upstairs bedrooms - especially children's bedrooms - you can use a standard 2-inch-by-10-inch roof system with a flat ceiling and structural insulated panels (SIPs) as an alternative to timber framing.
When it comes to cost, some people don't want a lot of wood beams in their home. Conventional stick framing is generally less expensive than timber-frame construction. For most parts of the construction, though, SIP construction is comparable to stick construction in cost and is definitely more energy efficient. So when we design a hybrid home, we incorporate as much SIP construction as possible.
If someone is building a small vacation home or cottage, they should consider a less-expensive hybrid home. One of our most popular standard models, the Carpenter's Cottage, is a hybrid that won a Gold Award and Honorable Mention for Best in Show at the New Hampshire Home Builders' Awards because of its design, energy efficiency and low maintenance.
Q: SIPs sound like a wonder material. What are they made of?
A: SIPs are an engineered 'sandwich' or laminate filled with insulation that forms a continuous thermal blanket, or envelope, around the outside of the timber frame structure. There's structural facing or sheathing on each side that forms the structural walls and roof of the home. Panels are either 4 feet or 8 feet wide; lengths vary from 8 feet to 24 feet.
Q: It probably makes sense to use timber framing in the great room and kitchen, but are there other areas where it makes sense - and why?
A: When deciding which areas of your home to timber frame, it's important to think about how the roof of the home will be designed. Then decide which roofs - if there are multiple roofs - will be timber framed and which roofs will use SIPs or conventional construction. It's much easier to use one method of construction for an entire roof. No matter what type of home you're building, it's always less expensive to design a home with fewer rooflines.
You need to establish priorities for the entire house and then for each wing, section and room. This will make it easier to work within your budget.
One of the most popular hybrid plans we design is a timber-framed center section with one or two conventional or structural panel wings for the bedrooms, dining room and mudroom/utility room.
Almost all of our homes are designed with a manufactured I-joist second-floor system, which creates a cavity and makes it easier to install plumbing and wiring; it also reduces noise between floors. They're usually less expensive than timber-frame floor systems. If the budget allows, both floor systems can be used together to create the beamed look in the first-floor ceiling, and you'd still have the floor cavity above the beams for the mechanical equipment.
Q: Even if my builder is conventionally framing the rest of the house, is it a good idea to find someone who's dealt with timber frame or post-and-beam structures before?
A: The general contractor is responsible for the actual construction of the home. He takes the house from foundation to finish. During the construction process, the contractor will manage the job site and supervise everyone from plumbers to electricians.
While experience with timber frame homes is helpful, it's not absolutely necessary. What's important is that the designer and/or the timber home company are able to communicate to the contractor the construction details unique to timber framing.
Every timber company handles the frame-building process differently. Whether you're building a full timber frame home or a hybrid, you need to find a quality custom builder through references or by checking with a local home builders association.
If the general contractor isn't familiar with timber framing, many companies like ours can arrange to have one technical assistant or a whole crew go to the site to coordinate the timber frame raising and panel installation. After the timber frame and panels are finished, the house is completed the same way as a conventional home.
If your plans and an interior-specification list are complete, you should get two costs from the general contractor: site costs and overall build-out of finish costs. This will allow time to adjust the budget before running into additional expenses during construction.
Many builders are unfamiliar with timber framing and SIP construction. With a detailed set of home plans and an interior specification list - along with assistance from the timber company - any good custom builder can build a timber home.
Q: Are there any special building-code issues that I should know about?
A: No, but it's important to have the building reviewed by the local building department, which most often will require engineer-stamped plans.
A timber home with a SIP enclosure system surpasses energy and structural codes when properly designed and engineered. Beam sizes and point loads are carefully calculated to address seismic conditions as well as snow and wind loads.
Q: What types of truss designs make the most sense with hybrids?
A: Since hybrids are designed in "sections" or wings off of a main timber frame section of the house, any type of truss system can be used. Hammerbeam trusses are used in a more elaborate timber frame, while king-post trusses are used in the majority of timber homes.
Here's a rundown of trusses - from the most expensive to the least expensive: hammerbeam, queen post, king post, principal purlin common rafter, collar tie common rafter, ridge beam common rafter.
Q: Do you still reap the same energy-efficient benefits with a hybrid?
A: The energy-efficiency in a timber home - whether a full timber frame or a hybrid - comes from SIPs. Panels have a significantly higher R-value than a conventionally framed home, and they also help reduce heating-and-cooling equipment costs. According to the Structural Insulated Panel Association, home owners can cut energy costs by up to 50 percent by using SIPs. (Check out sips.org.)
In hybrids, we design unframed sections and wings with SIP walls and roof systems, which keep the thermal building envelope consistent. Or, where clients want to have flat ceilings in hybrid areas, we design SIP walls with conventional stick trusses using 12 inches of batt insulation to get a high R-value in the ceiling. The space above the ceiling is then left unheated as cold attic space.
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