Livable Attics: How to Build Them and Why

An attic loft is nothing without plenty of light and air. Today's roof windows trace their ancestory back to Danish inventor Villum Kann Rasmussen. He pioneered reliable, high-quality roof windows beginning during WWII and spreading world-wide over the last 60 years.

An attic loft is nothing without plenty of light and air. Today’s roof windows trace their ancestory back to Danish inventor Villum Kann Rasmussen. He pioneered reliable, high-quality roof windows beginning during WWII and spreading world-wide over the last 60 years.

On the surface, you might think people own houses to keep warm and dry, but that’s not entirely true. The most successful contractors understand that a powerful – and potentially profitable — motivation is the quest for a home that boosts its owner’s sense of well being. Building feel-good houses is where the biggest bucks are, and all-season attics can be a powerful part of that formula.

In a world where basic housing needs are routinely met with slim profit margins, some clients will pay top dollar for unique details that are in short supply in today’s cookie cutter homes. Boosting both your profit margin and reputation are why you should consider developing the selling skills and attitudes necessary to create and sell livable attic lofts in you projects.

Every sloped-roof has some kind of attic space underneath, but most are about as inviting as the crash zone around an overturned lumber truck. The difference between a well-appointed attic loft and a tangle of congested roof trusses begins with simple design features. Of the six main design tactics that allow all-season attic lofts to function in harmony with the rest of a house, the most important actually redefines how you build a roof in the first place.

SIPs for the Roof

roof_sipsAnyone can stuff fiberglass batts into rafter spaces and call it an insulated attic, but this approach is destined to fail because of the hazards of internal wintertime condensation. And besides, framing a roof with rafters is enough work as it is, without also having to wrestle with dozens of extra bales of fiberglass and rolls of poly.

A faster, cheaper and more effective approach for building an all-season attic involves structural insulated panels (SIPs). These factory-laminated sandwiches of foam and OSB are self-supporting structurally. They’re also highly energy-efficient and very simple to use.

SIPs_roof_steepSIPs eliminate the need for both rafters and trusses, relying instead on ridge and valley beams for support. If you’ve ever built a house out of playing cards, you’ve already mastered the concept behind the SIPs roof. You’ll find 8 1/4”-thick panels are typically used to build roofs in Canada, and materials of this kind are able to span about 20 horizontal feet without intermediate support. Hoist the SIPs up with a boom truck, fasten them down with extra-long screws, and then shingle the top and drywall the underside. That’s all you need to do to create a dry, warm and fully heatable attic space.

High-Pitch Gables and Dormers

roof_cascade2If you’re going to the trouble of building an attic loft, you’ll need to consider a roof pitch that’s steeper than typical these days. Sure, any roof around 12/12 is a hassle to build and shingle, but the payoff is worth the high-value space you create underneath. Roofs with a 45 degree slope are especially handy when built with SIPs because the roof and eaves detail become so simple. This approach maximizes the number of cuts that can be made at 90 degrees. Building a scale model with 1/4-inch foam board is a great way to convey the steep-roof concept to clients while wrapping your head around the building task.

Soundproof Floor

dricore_overallWhen your client climbs up into their attic loft, they probably want to shut out the rest of the world. That’s why sound-deadening features are worth considering for any finished attic space. One excellent option is those OSB basement subfloor panels hitting the market these days. Offered under brand names like Driflor and Subflor, both types include a dimpled plastic sheet bonded to the underside of tongue and groove OSB panels. Place these on top of the attic subfloor before installing hardwood, laminates or carpet and you’ll boost the sound resistance of the assembly a lot.

Spiral Staircase/Ladder Stair Access

karina_stairsYou’ll gobble up way too much floor space with a regular staircase leading to an attic loft, and that’s why you need to consider alternatives. One practical, elegant option is the factory-built spiral staircase approach. The best manufacturers offer online design tools that allow you to dial in the overall rise, diameter and tread configuration you want. If the budget is tight, or you really need to minimize the staircase footprint, consider the site-built ladder stair.

Knee Wall Storage Zones

kneewallAttic spaces typically have roof slopes that extend right down to the floor, and the best way to deal with the potentially unusable space in the corners is to frame them in as a knee wall storage area. Trouble is, that can be a big hassle unless you do the work early on.

The best approach is to create framing and sheath it before the roof goes on. That way you have space to work. Sheathing the inside of the knee wall area with plywood is easy, adds considerable strength to the structure, and even looks good enough for a low-slung storage space when painted white. It sure beats drywall, both in performance and ease of installation. Create a very short knee wall out near the edge of the roof, then one higher up to define the knee wall storage area. If any parts of the house down below need a source of outdoor light, consider running a tubular skylight through the knee wall zone.

Split, Ductless Air Conditioning

mini_split_a_c_mountedThe challenge of keeping an attic space cool in the summer is greater than with any other part of a house because attics bear the full brunt of summertime sunshine. And while operable skylights and ample insulation might be enough in some cases, they might not. How do you know during the planning stage?

One option that clients welcome is the split, ductless air conditioning system. It won’t take more than a few hot days to determine if supplemental cooling help is required, and that’s where the flexibility of a split system comes in handy.

Instead of roughing in for ventilation ducts or a window air conditioner before you know if they’re really needed, split systems can be installed very easily after the fact with just a couple of holes drilled in an exterior wall. With the compressor sitting outside (as much as 75 feet from the area being cooled), and an interior, wall-mounted unit in place, extra cooling can be added to the attic later as needed. This system is also quiet and energy efficient.

Roof windows are an essential part of transforming an ordinary attic into a spectacular space. One of four wide-opening Velux units, they offer a 25-foot high vista, as well as the kind of generous cross ventilation required to keep an attic comfortable in summer. Photo credit: Robert Maxwell

Openable Roof Windows

No matter what kind of A/C you install in a liveable attic, don’t attempt to build one without putting in openable roof windows. There’s simply no substitute for the fresh air they bring into the attic and the rest of the house. Opening them a little in hot weather even allows central air to cool upper storeys better.

Livable attic lofts are a win-win proposition, offering terrific value for clients and a competitive advantage for builders who know how to take advantage of the new technologies that make them possible, comfortable and affordable.

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Posted on September 2nd, 2015

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