Converting A Garage Into A Livable Space….
Takes A Little More Than Drywall And Some Paint
Now that we’ve recovered from the blur of holidays from Thanksgiving to New Years, we bring a close onto 2019 and with the New Year have been working on a lot of unique and exciting home projects for others celebrating 2020. I am proud to present the ninth post for the Video + Blog series “What the Hell is Architecture?” A series that will present Case Studies, Code Commentaries, How-To Videos, and anything else that comes to mind to try and get the word out on what Architecture, Engineering and Construction ACTUALLY is. (Something the industry has done a poor job of enlightening the public on.)
With the start of a new decade, there is no shortage of people investing in large scale remodels of their homes. One such project type that we have already seen an influx of is the conversion of attached garages into livable space, offices, bedrooms, living rooms, etc. However, like all home remodeling projects, there is much more involved than simply submitting a building permit and installing some drywall.
The “Thermal Envelope”
A term we are going to keep referring to is “Thermal Envelope.” This is the concept that the entire exterior of your building should meet certain energy code requirements, mainly that it is insulated enough to prevent passage of heat or cold throughout your walls, floors, roofs, etc. If its simpler to imagine, pretend you are cutting your house in half and start tracing the insulation at the floor, you must be able to draw a continuous path around the entire profile without any breaks. (Windows and certain elements are allowed, but even the amount of these elements is limited to prevent energy loss.)
Insulation and R-Values
The resistance of an element to heat or cold movement is known as R-Value. The higher the R-Value, the better insulation provided. Every building element has an R-Value, but the reality is its all negligible in comparison to Insulation. To put that into perspective, wood has an average R-Value of .75 per inch, while Polyiso Rigid Insulation has an R-Value of 5.5. So, if you had to insulate a wall to meet R-21, you would either use 4 inches of insulation OR 28 inches of wood. Easy choice, so moving forward on this post we will be referring to insulation solely.
Residential Energy Codes
How insulated your roofs, walls and floors must be is dictated by the Energy Code, specifically the Residential provisions in the code. (Which are significantly more stringent than commercial properties.) An Architect will not only be required to detail this in their building permit submission, they most often will be required to submit reports verifying the building envelopes is compliant with code. (ResCheck is a free program provided to everyone that can provide this information, sadly it is not particularly user friendly.)
Insulate Your Garage When You Can
If you are converting your existing garage, then sadly this advice won’t help you. However, if you are building a house, INSULATE your garage as if you want to make this conversion down the road. A lot of new homes are built with an uninsulated garage, presumably to save money…. however, the amount you are saving by not having this done is a minuscule spit in the bucket compared to the entire construction. Not to mention, whether this conversion ever happens or not, it is only beneficial to have an insulated garage. (How many people dread taking the garbage or recycling out to the garage in fear of the painfully cold floor punishing those who didn’t have the energy to put shoes on?)
Insulating the Walls and Roof
Looking at the entire process required for this conversion, the walls and roofs CAN be the most “straightforward” part. If the wall studs and the roof rafters are deep enough, then the cavities between studs simply need to be insulated, as well as a Vapor Barrier installed. Gypsum Board can then be installed over it and painted per the owner’s desires. It is also often easier to simply insulate the pitched roof and then leave the pseudo “cathedral” ceiling exposed, making the room appear much grander in scale. (A dropped Ceiling can be installed but requires additional ceiling framing and structure and is not always worth the cost.) Current Energy codes require at least a 2×6 to provide the depth required to meet minimum R-Values. This is rarely an issue with the existing roofs, as this is a common roof rafter size. The walls however are very often only a 2×4, which may require more wood installed at each stud to create a deep enough cavity.
Exposed Foundation Wall, Holds Up The House But Leaks All the Air
The previous statement of walls being easy to convert must have a footnote regarding the lower 6 inches or so. Most often, a portion of the concrete or concrete block foundation wall is above grade, to provide protection against water damage. This provides a prime example of “Thermal Bridging,” which is the exact thing we are legally required to prevent. “Thermal Bridging” is exactly what it sounds like, it is an element that provides an easy path for heat or cold to move through. An exposed piece of concrete, even in a heated room, will be freezing to the touch in the winter, forcing more heating to be required and loss of heat through it…both wasting a lot of money. This element must also meet R-Value requirements, so we can’t simply put drywall over it, so often the best solution is to add 2×6 studs along it and insulate it like the wall assembly above it…This creates a small ledge at the perimeter of the room that may be less than ideal for some, however it also provides a design opportunity. (Often this ledge is perfect for radiant baseboards that tend to be installed.)
Do I Have To Rip Out My Floor?
“Thermal Envelope” requirements do not end at the floor; Energy Code usually requires that beneath the slab is insulation. Now if your slab was not insulated, which it often isn’t, you won’t have to rip it out. Many municipalities will allow you to insulate above the floor. This can be done with “sleepers,” studs laid on the floor and spaced similarly. Once the studs are installed, the process is very similar to the walls, a vapor barrier is installed, stud cavities will have insulation between them, a ¾” layer of plywood substrate is installed above and then whatever flooring the owner chooses can really transform the room into a living space.
Better Doors and Windows, Nothing Is Immune To Building Codes
Often the doors and windows that were installed in an uninsulated garage are very poor performing in terms of energy resistance. These elements also must meet minimum performance requirements dictated in the code, thus must be replaced. This is a perfect opportunity to install a shorter door, which will be required if the floor is raised to insulate above it.
The Biggest Door
What tends to be the biggest hurdle in a garage conversion is the issue of what to do with the garage door? Very often, the best answer is to remove it and have a wall framed in its place. The Residential Building Code requires a certain number of exits from this space depending on the square footage…this new opening provides a perfect place to install a Casement window which can meet this exit requirement. In fact, the size of the garage door requires a larger structural header above it, so a window installed at the same height can continue using this header. As mentioned only a few sentences ago, this is the part that can be the most “difficult,” the reason being that framing a wall in the existing opening is not challenging…making this new portion of the exterior wall match the rest of the wall is almost impossible however. Many municipalities do not want to see a house with an 8 foot by 16-foot portion of the siding to be glaringly in contrast to the rest of the house. This is avoided by removing all existing siding on that side of the house and installing new on the entire exterior. (Not the cheapest option, but the curb appeal added offsets it significantly.) If the foundation wall is exposed on the perimeter of the house, then at this new opening the same height and material must be installed as well to match existing.
Stepping On Up…Or Down
The garage is almost always at a lower floor level then the main house. This leaves us with two options, build up the new converted space to be at the same floor level, or have a step up into the house. If you do proceed with the steps into the house, they must meet minimum stairway dimensions and handrail requirements. Simple rule of thumb… never have a step that is taller than 7 inches and it CANNOT be less than 11 inches deep. If you install the converted space at the same floor level as the house, these same requirements must be met to the transition to the exterior.
Transforming Into A Truly Livable Space:
Closets, Heating, Cooling, Plumbing and Electrical and Creature Comforts
If the garage is being converted to a bedroom or will contain a bedroom, it is worth noting that a bedroom is LEGALLY required to have windows to the exterior and a closet. This is best installed along an exterior wall, this also provides a great opportunity to newly installed piping if a bathroom is being installed, as well as some conduit lines for whatever heating or cooling system we install. If the garage is not insulated, then it also has no heating or cooling provided, two vital things to make this into a livable space. A Mechanical Engineer can examine the existing systems to see if they can handle the additional heating and cooling load. If they cannot, or if the owner does not wish to install new HVAC systems and duct work, then a much cheaper alternative is to provide radiant baseboard heating along the walls and a ductless mini split air conditioner system. The mini split can be installed anywhere at the top of a wall, with conduit run to an exterior condensing unit, and the baseboards only require an electrical connection. These are much cheaper initially, but increase your monthly energy bills, you will have to balance whether it’s worth the investment for new HVAC or not. Since the goal is to transform this into a livable space, we can’t forget smoke detectors, light fixtures, outlets and plenty of other electrical items.
Your Town Cares About What Happens To Your Car
There is one final constraint to review with your local municipality, or more accurately the FIRST thing that needs to be reviewed. That thing being if your local zoning code has parking requirements that will not allow this conversion to happen. Some municipalities may not allow this as it will remove covered parking for your vehicles and force you to park outside or in the streets…Even if you are already doing that, the municipality does not care, this needs to be discussed with them before even a single design is started.
If your garage has devolved into a cluttered, dusty and breezy storage room that is never interacted with, then converting it could be a no brainer to adding size and value to your home. But even if all your construction is occurring inside the house, it is considered a “Change of Use” for that space and will almost always require a building permit and review.
Converting a garage may not be the most challenging construction project, but it is still necessary to consult with a Licensed Architect to avoid any last-minute surprises with the building department.
If you feel I missed the mark or am misinformed on any aspect of what I wrote, please let me know.
If you did enjoy the post or have any ideas or questions you would like to see or hear about in the upcoming posts and videos in this series, please let me know that as well.
Thank you all and have a great day.
- Bryan Toepfer, AIA, NCARB, CAPM
- Principal – Architect
- TOEPFER Architecture, PLLC
- Direct: 518.443.9366
- Email: firstname.lastname@example.org
- Website: www.toepferarchitecture.com
Let’s Build Something Together