Shop Under Garage?

[Ed Weiser]

If I had a choice, I would place as many windows into the space as possible. Even if this means window wells, I believe it would be worth it. My shop is in my basement now and even though square footage is not a problem, the absence of natural light is unpleasant. Do everthing you can to secure natural light. On the subject of air conditioning, assess your needs carefully. Cooling will not likely be a problem--dehumidification will. Don't oversize your unit. In floor heating would be great and could easily work off your home system as a separate zone without transfer of any dirt or dust into the house. Lastly, DO NOT bury your DC ducting in the concrete slab. The reasons are many including potential for water infiltration, encouraging excess cracking of the slab, potential interference with your heating system and, most of all, the total absence of flexibility if you decide in the future to change your shop layout! Hope this helps. I've learned from the mistakes I've made (many.) Good luck. Building a house can be very exciting (and stressful without proper planning.)

[Karl Laustrup]

He also said I can have floor drains in my garage if I want.
-Kevin

Kevin, do this. Have a drain put under each vehicle. Make sure the slope to the drain will encompass front to back and side to side of each vehicle so the runoff will all go to the drain.

[Ray Bersch]

Jim, I think you have some wrong info on pouring this type of foundation. A different mix is used than with a metal or wood formed pour and it is accomplished in one pour. The pours I have witnessed have actually been pumped not poured. Set up time is longer and the cost is likely to be higher.

Termites do not live in the foam forms. In fact, they would not even penetrate the foam. Extermination of termites is best accomplised by treating the ground around the foundation and the nests. Interior treatment is not appropriate unless there is infestation and with a poured foundation, that infestation will be in the wood above ground - with a block foundation, termites can penetrate cracks in the block and move up toward the wood frame - not the case with poured foundations.

I often have problems with subs who have learned to do things one way and will find fault with anything they are not familiar with - so ask around.

[David LaRue]

I have assisted in the construction of a several precast concrete homes in the Detroit area. The whole house was concrete block, with precast floors & wood truss ceilings. We used corefil in the block walls for insulation, and we drywalled the walls, and skimcoated plaster on the ceilings. You could not tell the building was concrete when it was done. The houses hold their heat, and stay cool because once you heat or cool that mass it stays very consistant. I woul not hestitate to make a house this way, and having a shop below the gargare mkes sense to me especially if it is a walkout.

[Rob Russell]

The idea of a basement shop with ~ 10' ceilings would be a dream to me. Radiant heat in the floor is definitely the way to go. You will likely need a dehumidifier for the summer - consider a drain for it. Window wells for natural light also provide a source of fresh air if you're spraying finishes. Just make sure the window wells are properly sealed and I'd suggest running drain pipes from the wells down to your curtain drains. Even if you can't do the windows, with lots of light it'd still be a nice shop. If you can, fit a sleeve for an A/C unit in the end wall. That would help keep the shop dry in the summer, too.

If I had the opportunity to build a shop like that, I wouldn't hesitate for a minute. I would also consider enlarging the garage a tad - the extra depth width is handy in the garage for snowblowers, lawn mowers, et al. That fact that the basement under the shop gets bigger is just pure coincidence .

Rob

[Gary Hoemann]

Kevin, i have been asking myself the same questions when planning a new home. I think everything you want to do is very doable and I also realize that I myself would not spend the money needed to extend hot water, sewer, and other things to a seperate building. I'm in Tennesse so some of it will be different, but with a walk-out basement andd higher ceilings, I think it would have a lot of advantages. One thing I'm still trying to figure out in my mind is how to keep vibration-type noise from migrating upstairs--like d.c. noise. We are a little further out on actual building--good luck.

[Jim Becker]

I was going to hang the ducts for dust collection from the ceiling but then I realized I can put them in the floor before the concrete gets poured.

I would recommend you avoid this, Kevin. It makes it impossible to adapt your shop over time as your needs and tools change and it also makes it difficult to deal with clogs, etc. Overhead, despite the appearance and challenge relative to lighting is generally the best and most efficient way to install dust collection duct. IMHO, of course.

As to the general idea you have, I like it also as long as the ceiling height is where you want it to be. The hydronic heating is also a good idea...separate zone, however, so you can run it lower than the house if you choose.

[Jim Dunn]

Don't, I repeat, DO NOT put drains under cars if they go to a septic system. Any gas or oil spills will end up in those drains and could damage your treatment system.
I believe code here requires drains and a "step" down into the garage so as to avoid gas spills from going under the door, into the house.

[Kevin Post]

Don't, I repeat, DO NOT put drains under cars if they go to a septic system. Any gas or oil spills will end up in those drains and could damage your treatment system.
I believe code here requires drains and a "step" down into the garage so as to avoid gas spills from going under the door, into the house.

I've been thinking about that Jim. The house will have a septic system, just as my current home does so I'm down with the whole bacteria is my friend thing. If the floor drains go to the septic system, I'm not putting them in.

I was told the step-down to the garage from the house is related to carbon monoxide gas rather than gasoline. At minimum, I was told we'll want a lip between the garage into the house to keep CO from seeping in from running vehicles because it's heavier than air. The other thing they do is pitch the floor toward the garage doors rather than the entry to the house.

I never really considered these details until our contractor mentioned them. I'm really cheap when it comes to stuff I think I can do myself. However, he has a lot of great info and I know his experience and efficiency will be worth the cost. I'm a computer guy who dabbles in this construction stuff. I'm glad I have someone else running the show.

[Bart Leetch]

I would have to worry about having a door between the shop & house because of smells like finishing migrating into the living area.

As to putting the DC & air in the floor thats no problem this has been done in commercial shops for years very successfully by pouring a trench down the center of the length of the shop in the floor with a lip on each edge & just out from the wall along the length of the shop & using thick wood or steel plate to cover the trench. This way you can access the system should you have any problems. I see no problem with doing the same with the heating & or AC. I would think that you would need less heating & AC with this ICF system so the ducting may not need to be as large which would make it easier to install in a trench system.

Also with ICF's I would think the time savings would off set other costs incurred for building the shop under ground.

Is there some way that you could build the floor support so it has beam like supports that set on a wall that the top would be say 12" lower than the rest of the walls & put obscure glass between each beam so for say the length of your shop you would have about 25-30 10" x 12" obscure windows letting in light. My Dad did this in our basement between wood beams & it let in a lot of light.

[Kevin Post]

I would recommend you avoid this, Kevin. It makes it impossible to adapt your shop over time as your needs and tools change and it also makes it difficult to deal with clogs, etc. Overhead, despite the appearance and challenge relative to lighting is generally the best and most efficient way to install dust collection duct. IMHO, of course.

Two votes against dust collection under the floor so far...

I agree this limits changing the system later because once it's in, it's literally set in stone. According to my plan, the main run ( 6 inch PVC ) would exist beneath the floor and outlets ( 4 inch ) would come out of the floor at various points to be extended with additional pipe or flex hose. I'm planning one run along a wall and one diagonally to serve the middle of the shop. This is how my garage is set up now and it's served me well with no changes. The only difference is I'd bury the pipe rather than hanging it. The advantage is headroom.

I'm not particularly worried about clogs because the setup I have now has never clogged (not the main part anyway). The only clog I've had has been in the hose coming from the planer. The 6" PVC leading to the DC fed by smaller 4" pipes is the key I think. The only change I may need to make is a bigger motor and fan to generate more CFM because the runs will be longer.

Another reply commented that the pipe would increase the chances for moisture damage and cracks in the floor. I guess I didn't think it would be any different than plastic sewer line that typically runs under the basement floor.

Any more thoughts on this?

-Kevin

[Kevin Post]

Is there some way that you could build the floor support so it has beam like supports that set on a wall that the top would be say 12" lower than the rest of the walls & put obscure glass between each beam so for say the length of your shop you would have about 25-30 10" x 12" obscure windows letting in light. My Dad did this in our basement between wood beams & it let in a lot of light.

That's an excellent idea but I'm afraid I'm limited with what I can do with windows because of the house design.

For those playing our game at home... The front of the house faces south. The 3-car garage is attached to the right side (east) of the house as you face it. The garage doors will not face the street, it is a side entry garage. So the whole east side is out for windows because the driveway and garage doors will be there.

The house will have a brick veneer on the front (south). I think the type of window you're suggesting would interfere with the brick. I am planning to put a window or two in wells on that end, however. That way, I can open the windows and the door at the other end and get cross ventilation when the weather permits.

To the west is the house. No windows there. The entry door into the basement will go through a closed storage area and then through the mechanical room for the house. A total of three doors will separate the living spaces in the house from the shop.

On the north side is our walkout level with an outside entry to the shop. The door will have windows and I'm planning to add another one to the wall. I'm also trying to find a way to install a spray booth on that wall with a vent to the outdoors. Most of the year I could just open the windows to replenish the air that gets sucked out but wintertime is a challenge. I'd freeze... I guess I could postpone finishing until the weather cooperates like I do now.

[Jonathan Szczepanski]

I agree this limits changing the system later because once it's in, it's literally set in stone. According to my plan, the main run ( 6 inch PVC ) would exist beneath the floor and outlets ( 4 inch ) would come out of the floor at various points to be extended with additional pipe or flex hose. I'm planning one run along a wall and one diagonally to serve the middle of the shop. This is how my garage is set up now and it's served me well with no changes. The only difference is I'd bury the pipe rather than hanging it. The advantage is headroom.

I'm not particularly worried about clogs because the setup I have now has never clogged (not the main part anyway). The only clog I've had has been in the hose coming from the planer. The 6" PVC leading to the DC fed by smaller 4" pipes is the key I think. The only change I may need to make is a bigger motor and fan to generate more CFM because the runs will be longer.

Another reply commented that the pipe would increase the chances for moisture damage and cracks in the floor. I guess I didn't think it would be any different than plastic sewer line that typically runs under the basement floor.

Any more thoughts on this?

-Kevin

Kevin -

There is another option for keeping the duct work under the floor. You could build a false floor or crawlspace on top of the the workshop slab. You could then run the duct work, or any other wire or piping under it. If you screwed plywood on top of the floor joists, you would have the abiility to unscrew them and fix any clogs or other problems that would occur. Wood is also easier then concrete to walk on all day.

Just an option to mull over.

[Steven Wilson]

I'm not particularly worried about clogs because the setup I have now has never clogged (not the main part anyway). The only clog I've had has been in the hose coming from the planer. The 6" PVC leading to the DC fed by smaller 4" pipes is the key I think. The only change I may need to make is a bigger motor and fan to generate more CFM because the runs will be longer.

Kevin, if you want a bigger motor and impellor and run longer distances then you'll probably want to rethink having 6" pipe and maybe go with 7" metal. As for 4" drops, they may (sort of) work for very small machines but if you ever upgrade to a sliding table saw, euro combo machine, shaper, etc. then you'll probably want to step up and use 5" or larger drops. Once you've placed the PVC into concrete then you're stuck and any upgrades will involve ripping the floor up. So seriously consider placing your duct work into a channel that you can access and make the channel large enough to handle larger DC pipe and probably electrical conduit. Then you have the flexability to change. BTW running overhead isn't so bad. As for the door to your house (from shop), spend a little money and get a door that seals well. The steel doors used in recording studio's are air tight and are fairly decent at reducing sound transmission.

[Bill Lewis]

Two votes against dust collection under the floor so far...

Well here is one vote in the "for" catagory, with explanation.

I did run one duct under the concrete floor of my basement shop. I just had to do this for the TS at the very least (I ran a power conduit too). I think this is one tool that greatly benefits by this. TS placement is usually out in the middle of the floor, so having an under floor setup is ideal. I hate tripping over cords or stepping over flex duct.

BTW no leaks. My whole basement stays totally dry though, it too is a level walk-out.

I used 4" PVC Electrical conduit because it has very large radius elbows. Of course if I were to do it again, I would use larger diameter, 6" maybe. The conventional thinking at the time was that 4" was adequate. Now I am thinking that I will probably end up with an excalibur and I don't think that the 4" will handle it, but hard to tell at this stage. I have another drop nearby, that would do the trick though.

One caution about running the whole shop DC piping under floor would be that you have design it to maintain velocity as well as cfm. For example, a 12" diameter pipe running the same cfm as a 4" diameter pipe may not have the velocity to move dust and chips. This is one reason why DC ducting gets reduced farther from the unit. If you can come up with a good shop plan and design the system well you should have a really neat setup. You can also do as I did, and combine the two as needed.