Looking for advice on new garage construction

[Mike_72]

Hello everyone! I just stummble upon this forum by chance and absolutely love it. I am just about to begin planning for a detached garage on my lot in Montreal. Because I am in a densely populated area I am limited to 40 sq/m (430 sq-ft). I am going to see if there is any possibility of going larger but there is a good chance I will be stuck at that size. If that is the case I am thinking of doing an 18x24 with 10 foot walls. Things that are important to me on this build are:

-Vehicle lift
-Heat for winter
-Proper lighting
-floor drainage (cannot drain into municipal sewers)

I was hoping some of you who have been through the design/build process could offer some advice on what to consider prior to starting construction.

Mike.

 

[matt_i]

Its a very good idea to understand the local zoning, HOA requirements, and also local codes to which the building is to be built.

A good bit of consideration goes into the foundation design, basically dirt & concrete work. There are several types but understanding the "frost depth" in your location is key, it will tell you how deep you must go to keep the building from heaving after freeze-thaw cycles.

Its important to decide what parts of the build you are going to take on yourself and which ones are to be contracted out.

Always good to try to do research on all fronts, roofing, siding, insulation, electrical, etc. Many threads on here and if you spend time reading some old posts you will come up with a long list of ideas.

 

[ford33]

Recommend a full set of drawings for the structure, electrical, drains, doors, windows roofing and trusses. You need to show foundation elevations with height above ground for slab and for footings. If someone is building this for you they will use the drawings as the primary requirements for quoting and build.

There are plenty of threads on this site about how a foundation was constructed and not what was desired by the owner. See the recent thread about the garage slab being lower than the alley height by nearly 18 inches. See the other threads on finished wall heights not being built to expectations and therefore an already purchased lift could not be installed. See the threads about garage doors not fitting the opening or the door beam height too low for the pickup truck to fit into the garage. The list goes on and on.

Without accurate drawings you are at high risk of not getting what you think you are getting. When issues occur you will not have anything to prove who is right.

 

[mike in tucson]

IF I were to do my garage over, here are some considerations that I would think about more:
1. If the lift is down or partially down, can I still access the man door easily? Location of the lift vs. the doors/storage racks/etc is important
2. If I have a car on the lift and another under the lift, is the lighting sufficient to work on
the lower car?
3. Lift utilities should go UP, not down to the floor. I did do this on mine
4. Make sure that the underneath car clears the sagging ramps when the lift is up. I had to make blocks to raise my ramps about 2" when they are hanging free from the floor
5. Don't forget an outlet for the battery charger for the topside car....don't want cords on floor
6. Don't put lift too close to wall, leave room for car door to open ALL the way
7. Make slab thicker/stronger especially where lift legs mount
8. Plan for LED lighting for sure
9. Plan where your compressor goes

 

[Gerry347]

10 foot walls are a little short for working on a car while it's on the lift. Do yourself a favor go at least 12' if you can.

 

[Mike_72]

Thanks very much for all the replies, they are very helpful. I am going to have a company that specializes in garage construction do the construction for me, I just need to spec out exactly what I want. I do understand that the foundation will need to be thicker and the proper type of concrete for a lift to be installed and I would hope that they know what is required for that. I realize that 12 feet would be better for the lift but I suspect I will be limited in overall height by the city. I will inquire about this tomorrow. I understand that there are special trusses that can give a little more height inside while maintaining a 10 foot wall. I was looking at the Grand Prix line of lifts from bendpak and they seem to be perfect for my needs.

The Company that will be building it will be required to give me all the drawings so that I can submit to the city for my construction permits.

Any input on what the best exterior dimensions would be with my limitation of 430 sq-ft? I am thinking that 430 sq-ft isn’t really big enough for a 2 car garage, so I am guessing it should be set up like a good size single car garage. In your experience should I go with 21x21, 18x24 or 24x18. I know this is fairly subjective just looking for input.

Mike.

 

[Odes]

The one thing I miss the most in my current garage is the walls go right to the slab the last one I built I did a row cinder block around the perimeter and it was great for washing the floor and in the winter

 

[Mike_72]

The one thing I miss the most in my current garage is the walls go right to the slab the last one I built I did a row cinder block around the perimeter and it was great for washing the floor and in the winter

Yes, that’s a great point. I will definitely bring that up with the builder.

 

[Gerry347]

If I was limited to your options I'd most likely go with a 18x24 building so I have more room in front of a vehicle for a work bench and tool box. That keeps the longer sides for storage of uncut lumber or metal. I'd also suggest a single 9' or 10" wide door in the middle so you have a little more for larger items.

 

[Mike_72]

Is it typical now that you aren’t allowed floor drains which drain into city sewer system? What are the options to allow for slush and snow to melt off a vehicle or washing of a vehicle in the garage if you can’t have a floor drain?

 

[glentre]

I agree with ford33 in post #3 above that you need to have a complete set of plans but you also should have a complete and extensive set of written specifications on what is required for every phase of the work. There simply is not enough room on the plans to do this unless you include written specs as separate pages of the set of plans.

To prepare a proper set of specs, you will need to do your research and think carefully about every single phase of the work and get your requirements down on paper. Then, sit down with your contractor to go over the plans and specs before a contract is signed in order to review any suggested changes he may have for improvements or cost savings. He knows more about building than you do and will welcome your acceptance of his suggestions to change some things and to improve the build by doing things you are unaware of. The result will be a set of legal plans and specifications you both sign off and agree on, cutting errors, misunderstandings and arguments to a very minimum.

Too often on this forum, I see owners fighting with contractors and contractors fighting with owners simply because each has their own honest preconceived ideas of how the finished building should be. Without prior written communications between the two, there will always be a conflict which often results in construction delays, poor construction and legal actions.

Glen

 

[Parrothead]

Just things to think about adding now while it's being built. Make sure to have wiring for not only the compressor and power tools, but for an electric car. While you might not have one now, the landscape is changing and so too are car manufactures. Have the wiring there for charging stations now as it will be useful and will help with resale should you ever move.

 

[tomroblee]

Most jurisdictions prohibit floor drains in garages because they don't want gasoline, motor oil, antifreeze and other chemicals washed into their sewer systems or even dumped into the environment. If you install floor drains, the floor must slope toward the drain. A sloping floor can be a nuisance (for anything except drainage.) If you don't have floor drains, some portion of the floor should slope toward the door. Folks have been known to rough in floor drains which were capped slightly under the surface of the slab. They weren't visible during inspections, but the thin layer of concrete could be chipped away after the inspector left.

Washing cars inside a garage sounds like a good idea, but you don't want to spray everything in the garage in the process.

Scissor trusses and parallel cord trusses can give you additional head room. If you are planning on using an overhead door, you need to consider where the door tracks (and opener?) will be located. Taller ceilings won't do you much good if the garage door tracks are in the way.

If heat is a prime consideration, you need to consider insulation and ventilation. A vapor barrier under the slab is a good idea. Insulation under the slab or at least around the exposed edges is worth considering if you intend to keep the building heated for extended periods in a cold climate. Thicker exterior walls will allow for more insulation (with a slight loss of interior floor space and higher cost.) Scissor trusses are great for gaining additional height, but can limit the room available for insulation.

Don't forget to plan for anything you might want installed underneath the slab (water and drain lines etc.)

 

[polizei1]

I wouldn't (and didn't) do a floor drain for the reasons tomroblee mentioned. With a lift, you want the floor as flat as possible, even when using a 4-post. You do have some adjustment, but depending on the slope, you could run out. There was another member here who added blocks under the front two legs of his to level it out. While it can be done, I would rather not!

I would also recommend you increase the ceiling height, as 10' is not going to be sufficient, you'll want at least 12'. I used scissor trusses for mine, or you could use something like a coffer truss.

As for heating, I would definitely go natural gas if you can, a Reznor or Modine.

Lighting, I would look at LED shop lights, specifically Prime Lights Stingray's. Call them, they'll provide a design layout.

I would also suggest looking into flooring options prior to a concrete pour. I will be using Rust Bullet, so I made sure the contractor didn't add a finish or sealer to it.

 

[Oldbear]

I'll recommend scissor trusses and 12' walls if you can. The more headroom the better, and the extra wall space can be used for storage/shelving.

Plan for extra or future electrical needs. You might only need 110 volt now, but a new compressor or lathe - maybe a commercial lift will need 220. I have a 20 slot subpanel in my new shop and it fills up quick with compressors, welders, lifts and such.

I'm a fan of in-floor heat, but you need to plan, measure and mark for a lift. I my case I knew the dimensions of my lift before I installed the pex tubing. Go with as much insulation in the walls, ceiling and ground as you can. It will cost up front but save you over time.

And as far as a floor drain - you could do a sump, but then you need to pump it out or fish for that 10mm socket in 2ft of sludge. I'm the proud owner of a good floor squeegee and nice shop broom. My current garage floor gets a scrub and sweep often. I'm planning on getting a "parking pad" (big tarp with foam edges) to keep the road salt and such off my cement. My friends have one - haul it out on a nice day - spray it with water and drag it back in. Their garage floor is 3 years old but still looks new under the mat.

Plan your driving vehicles in and out. Are there any tight corners? Can you fit a Yukon in the left side of the big door? Will your 1967 Oldsmobile make the corner without having to cut down a tree? My neighbours must have thought I'd lost my mind when I was parking different vehicles between cardboard boxes and string. Mark it out with string and stakes. Walk around it, try to park in it. Go back to your days of make-believe and imagine working in that space - that's how I made a change for an extra 2ft on one end (slight shift of the door openings).

Plan ahead. Think about the plan. Replan. I did a lot of sketching before we even went to the bank or the building permit people. I had a well planned out shop before we ever put a shovel in the dirt... and that plan has changed as we went along.

 

[Mike_72]

Thanks again for all the information and tips, it is making this process a whole lot easier. Visited the Builder yesterday to discuss options and came up with a rough quote for the build. It looks like 18x24 is a big as I can do in my area and max height will have to be 14.5 feet. I can just barely get 10 foot ceilings and maintain a max height of 14.5 feet with 4/12 rafters. The builder confirmed that it isn't legal to have any type of floor drainage, even if it collects it in a barrel to be disposed of properly. He stated that most people have them make a "thin" area in the center of the slab that can be broken open after the inspections has been carried out. My concern with that is there would have to be a slight slope to the center of the slab which might cause issues with the installation of the lift. Would the slope be big enough to be an issue or is this not a concern? I am looking at getting the Bend Pak Grand Prix GP-7LC when its available which will fit nicely with a 10 foot ceiling. I realize this will not allow for me to stand under the vehicles but will certainly be better than laying on a creeper. I also requested to have the slab built up at least 12 inches on the perimeter to keep the lumber off the slab. the quote they gave was 28,000$ CDN tax in which includes the slab, 2x6 construction, all exterior finishings, 8x12 garage door, man door, one window (I can add more). What do you guys think of this price?

 

[polizei1]

I'm learning through my process to not settle...builders will tell you they "can't" do something even though they darn well can, they just don't want to do it because it's more complicated and/or more work. If you have local codes saying you can't do things, that's one thing...but why would you have a ceiling height restriction? That seems odd to me...

Anyway, just make sure you're getting exactly what you want. If you're not going to be happy with it, don't do it because you'll always regret it.

 

[nolimits76]

I'd spend a little more for a 4,000psi concrete mix. Also, maybe test the concrete myself for slump, air, and strength. It's easy to take cylinders and for $100 in testing you'd be reassured of the strength. Plus with people knowing your testing it ensures you get a good batch of mud.

If you don't know how to figure cubic yards: 18' x 24' x 6" (or .5', assuming you use a 6" thick slab - adjust as needed) = 216 cubic feet (sf3) / 27 = 8 cubic yards (CY).Assuming you have a 3' deep x 2' wide footing around the perimeter, that is: (18'+18'+24'+24') x 3' x 2' / 27 = 19 CY.

If you have an intermediate footing between the 24' span, or around the lift then it would be slightly more.

But roughly we are talking about 27cy of material. Add 10% for waste. Call it 30 yards @ $10/cy = $300 up charge.

Lastly, don't skimp on the reinforcing. Some like to do fiber reinforcing or wire mesh, but I'd just assume throw in #4 bars. Again, small up charges, but they make a difference on your slab strength.

 

[Lelandwelds]

Some places have almost no price difference for 4000 psi concrete with slump improvers. If you use the word "garage", some builders automatically pour a dish bowl or 2" drop over twenty feet toward the door. Work in "fab work" or "must be level + -~ 1/4" per 10 ft." Or something similiar. Use rebar and mesh if you like in floor heat someday. Use rebar and macro fiber . Tell builder "no burnishing concrete" if you want epoxy floors. I like door openings to be 3/4" lower than the floor.

Whatever you build, you will wish it bigger. Find some other place for lawn equipment and Christmas decorations.

 

[Hot Rod Grampa]

Another vote for details in writing. Assuming the concrete guy knows how much extra concrete and exactly where it has to be is risky. Concrete guy may be a sub and a wonderful adventure just turned into a legal nightmare. You need to learn a lot about basic construction and create a good rapport with your GC. You will need to ask questions and be able to spot a potential issue. For that you have to be able to work with the GC not be adversaries. Good luck and keep us posted.

 

[stm317]

Have a well thought out plan for insulation. The type of insulation you choose can have effects on building design and construction, as well as overall budget. If it needs ventilation, that should be part of the plan from the start. Being in Canada, I'd want that building to be very well insulated.

 

[Mike_72]

I'm learning through my process to not settle...builders will tell you they "can't" do something even though they darn well can, they just don't want to do it because it's more complicated and/or more work. If you have local codes saying you can't do things, that's one thing...but why would you have a ceiling height restriction? That seems odd to me...

Anyway, just make sure you're getting exactly what you want. If you're not going to be happy with it, don't do it because you'll always regret it.

The ceiling height restriction is really just limited by the fact the the city bylaw requires the top of the building to be no more than 14.5 feet so 10 is the best I can do with a standard 4/12 truss.

 

[Mike_72]

Thanks for all the info on the concrete guys, I am really going into this with very little construction knowledge. I am an aircraft mechanic by trade but have very limited knowledge oh building best practices. If given the open to have a center hole in the slab which just weeps into the gravel below or a slight slope towards the door which would be preferred? Keep in mind I’m in Canada so good chance there will be some good salty slop dripping in there from time to time. Will mainly be used for storing summer cars but will occasionally have to bring the winter cars in

 

[kbs2244]

When I built mine I acted as my own general contractor.

I went with 3 rows of block to get 10 foot eves with normal, stick built wall construction.
(8 foot walls on 2 feet of block)

https://www.garagejournal.com/forum/showthread.php?t=296292

Flat floor without a drain.
Don't wash in it and I didn't want to be tripping on it all the time.

Ridge beam roof construction to give a big, 14 feet to peak, vaulted ceiling.
(I love all that room up there)

My son is pretty well plugged into the local construction scene and we got a union carpenter he knew as the main worker after the slab and block.
(I have another son that is a mason and did the block)

The local Menards is 5 miles away and offers next day delivery.
The carpenter was good at knowing how much of what he would need and having me order it in time.

We went without drawings.
(The county only wanted a plot layout of where it would be)
An experienced crew, lots of communication as things progressed, and a general "match the house" on any appearance issues, worked fine.

It helped that I had a very good idea of what I wanted and was able to explain it well.
Mutual trust and respect was a given.
Weekly cash payment helped a lot also.

 

[MrSurly]

Are you limited to only the "standard 4/12" roof? What are the options for other pitches or truss types that will work there? I'm assuming that snow loading and wind requirements in your area likely mandate your roof design(?) Is it possible to even consider flat roof? You could gain a lot of room to raise a car!

 

[mineallmine]

You could get the scissor trusses made for a vaulted ceiling design. They are not much more and will allow more room for the hoist. I am also in Canada and what I did for my floor was slope it towards the garage door. I also have 18" curb walls so water will never get tot the base of the wood. Really glad I did. I think I went 4" slope over 32 feet.

One suggestion for the concrete. I had 32MPa concrete poured for my floor and it's great. The guy that did my concrete work was awesome and said the guys he uses for concrete are good. He added a powder that he floated into the surface of the slab before he did the power trowel work that he said hardens the top surface to 52MPa. It's main purpose is if you drop something heavy the harder surface will keep the concrete from chipping.

I dropped a claw hammer from the top of a 10' ladder when I was building and it hit claw first and never left a mark. It only added about $350 to the cost. I only built mine 2 years ago

 

[polizei1]

Well FWIW, if you're limited to a 4/12, I would imagine you could still use scissor trusses to get more height. Mine is a 6/12 and I'm using both normal trusses and scissor.

 

[Vintage Veloce]

I think it is a big mistake to use the builder for your plans. Too many possible conflicts of interest. Get your plans done separately by an architect or designer and read all the code on garages yourself. Do NOT trust anyone setbacks or height limits or size limits until you see it in the code, and understand it yourself.

 

[Vintage Veloce]

In my experience, garages are afterthoughts for most builders and the governmental planning staff. For instance, where I live the normal setbacks for a residence do not apply to "non-habitable buildings" like garages. But understanding this takes digging into the city code, and I actually had to explain and prove this to the city people that examined the plans. Builders often want to build what they know they can do safely and easily. You could easily miss out on what you "could do" if you limit yourself to the advice of a builder who may not have studied the code yesterday.

Also note that having your own complete plans allows you to get multiple quotes from different builders. In my case it was clearly worth the cost and effort to have my own plans.

 

[mineallmine]

Well FWIW, if you're limited to a 4/12, I would imagine you could still use scissor trusses to get more height. Mine is a 6/12 and I'm using both normal trusses and scissor.

He isn't limited to a 4/12 truss...he is stating that 14.5ft is the limit on height (4.5m in my area) so a 10ft ceiling is the best he can get with that pitch truss. But as you stated the scissor truss would gain more height for the lift.

 

[MrSurly]

In my experience, garages are afterthoughts for most builders and the governmental planning staff. For instance, where I live the normal setbacks for a residence do not apply to "non-habitable buildings" like garages. But understanding this takes digging into the city code, and I actually had to explain and prove this to the city people that examined the plans. Builders often want to build what they know they can do safely and easily. You could easily miss out on what you "could do" if you limit yourself to the advice of a builder who may not have studied the code yesterday.

Also note that having your own complete plans allows you to get multiple quotes from different builders. In my case it was clearly worth the cost and effort to have my own plans.

100% this. When I started by planning I got different setback numbers from various people at the city. 10' was a popular number (guess) for the side property line. Of course this was causing a real problem for other aspects. One person said they thought it 3' another said 4' another, 12'. I read everything, found a statement about 'accessory' buildings and I challenged their numbers. They relented and said, you're right, it's 3'. YAY!! (there's more)
AFTER submitting my stamped plans, a different department brought up a fire code issue: I can't use the 3' distance *unless* I can satisfy a non-combustibility standard ***.**. If I was building with cinderblock I might've been OK, but I wasn't. Unable to satisfy the requirement, I had to use the fire code's required default minimum 5'.
(NO one had guessed 5', btw.)

But that wasn't learned until quite a ways through the process.
The moral of all these stories: Get your design drawn up, preferrably 'engineered' and get the city permit in hand before building pads, buying materials.

 

[nolimits76]

But that wasn't learned until quite a ways through the process.

The moral of all these stories: Get your design drawn up, preferrably 'engineered' and get the city permit in hand before building pads, buying materials.

Depending where you live and how strict the inspectors are, starting w/o a permit can cause you a serious headache. Whatever PITA you think it is upfront, it becomes twice as bad when you get a pissed off inspector that wants to make your life miserable.

I built out an upstairs on a previous house, and lived where codes and inspections were very relaxed. Took some drawings I did in CAD and paid them a few bucks and all was good. I'm used to commercial and heavy/highway construction so I was good about staying in touch with the inspectors. Long story short, they spent maybe 10 minutes total on my property. Once after it was framed out and MEP was roughed in, and then once after it was finished. Hands down the easiest stickers I've ever gotten. But I drove my subs pretty hard to do quality work regardless.

It really goes along ways to show some respect to everyone involved in the process. I'd only flex muscle if I felt things were going amiss. On numerous occasions I'd drop by and bring the work crews breakfast or lunch, and eat and BS with them for a few minutes. This went a long ways with some small details and quality of build.