Origninal article by Denis Chamberland, translated by Deb Villeneuve
Of the questions which I am most frequently asked, I would have to say that this is right up there.
Although building codes and other standards will dictate how a home must be built and thus standardize the cost estimates to some degree, building a garage is a whole other ball game. A garage is as personal as the individual who wants it and the cost to build it will reflect the use that you have in mind as well as some other considerations.
Before getting started, the best place to start is your municipality to get a clear idea of the restrictions with regards to square footage, height, set back, what kind of slab foundation is required and other details. Even if you are thinking about an attached garage, the square footage permitted by your municipality may force you to a smaller model than what you had in mind. A good way around this is either by way of a breeze way or a separate garage in order to avoid having the size of the garage taken into consideration with the actual square footage of the home.
Now that we have an idea of size, the next thing to consider is the ground on which you want to build. You may want to opt for the independant foundation offered by a floating concrete slab or for a monolithic slab that is reinforced around its outside edge to better stabilize the outside walls and their associated loads. This variable alone will impact the cost between $1000 and $2500. depending on the type of foundation, the monolithic slab being the least expensive of the two.
How much of the actual work you are going to do yourself and will your contractor agree to do only the structural work in order to help you save money by letting you do the rest? This is another variable that can acheive $5000. or more if you are paying for skilled labour.
Do you plan to use your garage year round as a workshop? Will it be insulated to R13 using 2x4s or is an R20 rating with 2x6es more appropriate? Do you need heating? Electricity (if so, will it be 110 or 220)? Plumbing? A heated floor? How about the garage door? Utility door(s)? All of these options come with a price tag and can easily influence the cost by $2000. to $5000., depending on the size of your garage.
Another thing to consider is what to do with the optional bonus storage space that your garage model may have. Will you use it or will you eliminate it by using only pre-fabricated trusses or, if you choose to keep the bonus space, will it be insulated or finished with plywood only?
As you can see, the variables involved are numerous and this is what makes it difficult to arrive at a general estimate to build a garage but I have attached an example that was worked out by our head designer to give you an idea.
Lets say that you are interested in the stand alone garage model 2975-16 which is 16’wide and 24’deep. The exterior walls willl be 2×4 construction finished in vinyl siding on a monolithic slab, the bonus storage space will be used but not insulated and it will have minimal electricity without plumbing or heating. The slab and the roof will be done by a contractor and you will do both the inside and the outside finishing. The finished product will run about $16,000.