Garage Office

[nmadole]

So .... I am looking at buying a new house. I live in Northern Michigan.

I'd like to build an free standing office in the Garage. It will need to be insulated, have a natural gas line installed, and have electrical run. Size will only be around 200 sq ft.

A couple questions I have ....

What is the best way to construct the floor?
- Build out a platform as if you were building a shed
- Attached the Stud walls to the floor and don't worry about the concrete floor sucking up the heat
- Attach the Stud walls to the floor and build a Sleeper Floor from 2x4's
- Some other option?

Assuming I were to choose option 1 or 3 above; what is the best way to insulate the floor. Ridged insulation between the 2x4's or 2x6's in the Sleeper Floor / Platform Joists?

What would be the appropriate way to frame out the ceiling? Joists? 2x4's? I'd like to store stuff ontop of the office.

How difficult / costly would it be to get a gas line run to a gas heater inside the office?
How difficult / costly would it be to get electric run to the office?

Anything I am missing? Any bright idea's? Is any of this a blatant violation of "Code"?

 

[73RR]

Why do you need a gas line in 200sf? A small electric heater will suffice.
How far from your breaker panel ? How much power do you want/need for 'x'?
The warmth of the floor is proportional to the amount of insulation. Build a platform and sandwich some 2" R-Max between layers of osb/plywood/ or ?
If you want to store 'x' on top then use framing materials suitable for 'x' psf.

 

[happy2rv]

So .... I am looking at buying a new house. I live in Northern Michigan.

I'd like to build an free standing office in the Garage. It will need to be insulated, have a natural gas line installed, and have electrical run. Size will only be around 200 sq ft.

A couple questions I have ....

What is the best way to construct the floor?
- Build out a platform as if you were building a shed
- Attached the Stud walls to the floor and don't worry about the concrete floor sucking up the heat
- Attach the Stud walls to the floor and build a Sleeper Floor from 2x4's
- Some other option?

Assuming I were to choose option 1 or 3 above; what is the best way to insulate the floor. Ridged insulation between the 2x4's or 2x6's in the Sleeper Floor / Platform Joists?

What would be the appropriate way to frame out the ceiling? Joists? 2x4's? I'd like to store stuff ontop of the office.

How difficult / costly would it be to get a gas line run to a gas heater inside the office?
How difficult / costly would it be to get electric run to the office?

Anything I am missing? Any bright idea's? Is any of this a blatant violation of "Code"?

There's a lot left to the imagination here. I'm not sure there is a "best" way for all circumstances. Some of the answers depend on what's important to you and some depend on code. I believe there is a code requirement, at least in the latest building code, that living space be stepped up from garage space, so assuming it's classified as living space, building a platform might be a requirement.

You say free standing, so are you building 4 walls in the middle of the garage? If so, you're going to have an issue getting any kind of utilities into the space. Cutting and trenching to bring utilities in could be done, but would be expensive.

I believe there are specific requirements on where/how gas can be used, but that's way outside my realm of experience, so hopefully others can comment with more useful info.

There will also be requirements on wall floor and ceiling coverings to meet fire safety standards if it's classified as living space.

If it's not truly free standing, that changes some things. For instance, if it attaches to an interior wall, you might have a much better path to run utilities and it might be possible to heat and cool from your existing HVAC if it has sufficient capacity. You would still have to meet the other requirements.

 

[nmadole]

I appreciate everyone's reply's so far!

Why do you need a gas line in 200sf? A small electric heater will suffice.
How far from your breaker panel ? How much power do you want/need for 'x'?
The warmth of the floor is proportional to the amount of insulation. Build a platform and sandwich some 2" R-Max between layers of osb/plywood/ or ?
If you want to store 'x' on top then use framing materials suitable for 'x' psf.

I was thinking a Natural Gas heater would be most cost effective for maintaining a heated space during the long Michigan winter; would an electric heater not be too expensive to maintain 65 degree's 365 days a year?

I need enough power to the typical office supplies, a camera system and a heater if I don't go with natural gas.

I am going to see the house Tuesday, I will check where the breaker is

There's a lot left to the imagination here. I'm not sure there is a "best" way for all circumstances. Some of the answers depend on what's important to you and some depend on code. I believe there is a code requirement, at least in the latest building code, that living space be stepped up from garage space, so assuming it's classified as living space, building a platform might be a requirement.

You say free standing, so are you building 4 walls in the middle of the garage? If so, you're going to have an issue getting any kind of utilities into the space. Cutting and trenching to bring utilities in could be done, but would be expensive.

I believe there are specific requirements on where/how gas can be used, but that's way outside my realm of experience, so hopefully others can comment with more useful info.

There will also be requirements on wall floor and ceiling coverings to meet fire safety standards if it's classified as living space.

If it's not truly free standing, that changes some things. For instance, if it attaches to an interior wall, you might have a much better path to run utilities and it might be possible to heat and cool from your existing HVAC if it has sufficient capacity. You would still have to meet the other requirements.

Sorry for not giving more details.

4 walls, but in the back corner of the garage; but I would not be sharing the exterior garage wall. There would be a small gap between the walls ... I see clients and I want to have a space that is comfortable year round, and doesn't require people in my actual house.

I plan to pay an electrician to rough in the electric and the same with the gas line (if necessary).

 

[Stuart in MN]

Even the smallest gas heater may be too large for a space that's only 200 square feet. If it's well insulated a small electric heater should keep it comfortable, but you'll have to do the heat loss calculations to figure it out.

 

[nmadole]

Even the smallest gas heater may be too large for a space that's only 200 square feet. If it's well insulated a small electric heater should keep it comfortable, but you'll have to do the heat loss calculations to figure it out.

I was looking for min. sq ft. requirements on the Vented hanging gas heaters and I couldn't find anything

 

[happy2rv]

I'm not sure if you would have to trench the concrete or if you could run conduit from the wall that's close by, assuming the gap is small enough that it would be a trip hazard. You might also be able to drop conduit from the ceiling. Not sure about gas though.

Since this is going to be used for business purposes, there may be additional code requirements and/or issues with insurance. I would check with the local building department since they are ultimately the ones who will have to sign off on it.

My first thought for heating/cooling would be a ductless split system, but I'm not sure how well a heat pump would work in that climate.

 

[matt_i]

I think I'd build 6" of foamular insulation up off the concrete and lay 3/4" T&G plywood directly on top of that with no joists. Alternate the layers and use Loctite PL300 construction adhesive to adhere the foam and make the stack more solid. 2x6 stud walls up to height, finish over top with 2x10 ceiling joists on 24" centers. Roxul R23 in the walls, R-30 loose fill in the ceiling (could be more with deeper cavity) I would start with something like a 1500W space heater*. My guess is if that's left to run unattended it will keep the space warm enough for you. I would do some simple electrical controls to allow a thermostat to be used controlling a 24vac-coil contactor. The thermostat can be a programmable version so the temp automatically ramps low at night and then ramps back up when its going to be needed. Could even do a fancy Wifi thermostat for smartphone app control.

You could run a couple of 20A circuits or else a sub-panel. 1 circuit for the heater and 1 for everything else.

The natural gas furnace has the problem of being likely oversized for the space, then you also need to vent the exhaust gases, so its going to be a B-vent up and out thru a roof penetration.

*Some very rough heat loss calculation. using QdotsubA = delta T/R-value * (sq ft)

Lets just assume 75F temp gradient for worst day -10F outside to maintain 65F inside (Kelvin scales same as Fahrenheit for delta numbers)

There are 400sq ft insulated at R-30, Q(total/hr) is going to be 75/30*400 = 1000 BTU/hr

Sidewalls, assume 10ft tall 10x20 footprint, 600sf insulated at R-23, Q(total/hr) = 75/23*600 = 1900 BTU/hr

So roughly 3000 BTU/hr heat loss. 1kW = 3400 BTU/hr. Should be good with the 1500W space heater in my estimation. 100% efficiency on electric.

 

[nmadole]

I think I'd build 6" of foamular insulation up off the concrete and lay 3/4" T&G plywood directly on top of that with no joists. Alternate the layers and use Loctite PL300 construction adhesive to adhere the foam and make the stack more solid. 2x6 stud walls up to height, finish over top with 2x10 ceiling joists on 24" centers. Roxul R23 in the walls, R-30 loose fill in the ceiling (could be more with deeper cavity) I would start with something like a 1500W space heater. My guess is if that's left to run unattended it will keep the space warm enough for you. I would do some simple electrical controls to allow a thermostat to be used controlling a 24vac-coil contactor. The thermostat can be a programmable version so the temp automatically ramps low at night and then ramps back up when its going to be needed. Could even do a fancy Wifi thermostat for smartphone app control.

You could run a couple of 20A circuits or else a sub-panel. 1 circuit for the heater and 1 for everything else.

The natural gas furnace has the problem of being likely oversized for the space, then you also need to vent the exhaust gases, so its going to be a B-vent up and out thru a roof penetration.

Why would you suggest 2x6 stud walls? (Just wondering)

Would you just frame around the outside of the ceiling joists and put plywood ontop?

Would I need to anchor the floor insulation to the concrete?

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[matt_i]

Why would you suggest 2x6 stud walls? (Just wondering)

Would you just frame around the outside of the ceiling joists and put plywood ontop?

Would I need to anchor the floor insulation to the concrete?

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I would use 2x6 walls for the R-23 insulation you could get. Not needed for structure.

Another layer of 3/4 plywood could be put on top of the joists, I don't know the size or spans (etc) or how many big block engines are going to be stored up there ....it would be good to give the loose fill some time to settle down.

I would just use the Loctite PL300 to anchor the floor insulation to the floor. You just don't want it to slip. Should be mostly held in place by fitting it precisely between the stud walls. And I would use Tapcons or 1/4" wedge anchors to hold the bottom plate of the walls down.

 

[nmadole]

I would use 2x6 walls for the R-23 insulation you could get. Not needed for structure.

Another layer of 3/4 plywood could be put on top of the joists, I don't know the size or spans (etc) or how many big block engines are going to be stored up there ....it would be good to give the loose fill some time to settle down.

I would just use the Loctite PL300 to anchor the floor insulation to the floor. You just don't want it to slip. Should be mostly held in place by fitting it precisely between the stud walls. And I would use Tapcons or 1/4" wedge anchors to hold the bottom plate of the walls down.

The 3/4 plywood would just be floating ontop the insulation (floor)? Vapor barrier on concrete?

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[Marctrees]

One thing that is clear is NO need for gas line for that size room, even in Michigan.

Build a decently insulated room, the 1500w "Milkhouse heater" for literally $20 will heat it just fine, and best value all told overall by far.

Re - insulating the floor or not.

It won't make a huge diff in your heating cost, BUT, it will make a diff in comfort for your feet.

If your'e a cold feet prone guy, insulate the floor.

And, if you don't heat it most of the time, the room will warm up quicker if the cold slab is not able to absorb it.

All subjective. Marc

 

[matt_i]

The 3/4 plywood would just be floating ontop the insulation (floor)? Vapor barrier on concrete?

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Yes, my reasoning is the Foamular 150 has 15psi crush resistance, it scales up to over 2000 lbs/sq ft which I don't think you can exceed in an office Just need something to blunt the high heels (lol) and that's what the 3/4 ply is for. You could cover it with something nicer than that of course, hardwood, tile, whatever, budget is the only limit.

 

[Voi]

There is a product designed to go over concrete floors and have flooring installed directly over it. I just read about it on Green Building Advisor and have no opinion on it beyond the thread I read:

http://www.greenbuildingadvisor.com/community/forum/general-questions/100637/quik-therm-warm-floor

And here is the product:

http://www.quiktherm.com/features-highlights-warmfloor

Personally I'd just buy XPS or EPS with the proper PSI rating and put plywood over it and then flooring. I might run tapcons through the plywood and foam and into the slab. Countersunk flush with the plywood.

I would avoid building a grid of lumber to hold up a subfloor unless the garage floor is sloped more than normal. Like enough to be awkward to clients.

I also wonder if something like horse mat would be rigid enough to support flooring yet be modular yet still provide a break from the cold floor.

If you're set on natural gas I'd look into a wall mounted NG heater (vented) or one of those marine heaters and convert it to natural gas.

A small thermostatically controlled NG fireplace is another option. I see them in large bathrooms so I assume it would work.

 

[rburke65]

Well insulated 200 sq. ft. office.... a small elect. heater won't have any problem.

 

[nmadole]

Well insulated 200 sq. ft. office.... a small elect. heater won't have any problem.

I think I'm going this direction... I'm having a hard time finding one that hooks up to standard thermostat. Any suggestions?

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[James-W]

I would use these on the concrete floor.

https://www.samsclub.com/sams/util-...24-x-24-8-tiles/107930.ip?xid=plp:product:1:1

I would insulate the walls and the ceiling as much as possible and I would go with electric heat. Being such a small area, and being well insulated, a small electric heater should work well. Small electric heaters are cheap to buy, and they can be plugged in anywhere in the office. They do cost more to run than a natural gas unit would cost, but with such a small space to heat, I really don't see the advantage in getting a natural gas heater and running the gas, the mounting and the venting. With the electric heater you just buy it, you plug it in and enjoy it.

 

[Stuart in MN]

You may want to look at electric baseboard heaters, you can get them with a thermostat built in. Most any big box store should have them.

 

[Strouty]

I have a small insulated office in my shop, I use an exterior wall on two sides so it has windows. The room is very easy to heat, I use a 1500 watt oil filled radiator style heater so the electric baseboard would work well, I just don't have the wall space for one. The one thing I wish I had done was deal with the floor, the concrete is very cold all year and ***** in the winter. If I could do it again, I would add in floor heat.

I second the 2x6 walls and roxul, it will add warmth and sound deadening as well. I went wicked overkill on my ceiling so it will support anything I want to put above it.

 

[Chilliwack Murray]

I have 380sq ft and a 1500w heater had no problem well below freezing but why not install one or two baseboard heaters. The newer ones have a flow through design and get hotter than traditional style units so they create good air movement and even out the temperature. Spend a little extra on insulation and sealing up the drafts instead of the gas line.

I have a 1500 and a 750 watt baseboard and two outside walls with 4 windows. HD sells a $20 wall thermostat that actually has variable output so they are only on full when i first turn the heat on, the rest of the time they are barely on. At 240v, 2250w is less than 10 amps so a single circuit runs it. Most of December was well below freezing and non stop wind here and i don't think it cost more than about $20 to keep it around 66 every day.

 

[ard]

I'd be more focused on making this 'office for seeing clients' be visually appealing. A free-standing building INSIDE a garage, could be weird if done wrong.


How big is the garage that this 200sqft structure the will be built inside? How will clients get into the room?

 

[nmadole]

I'd be more focused on making this 'office for seeing clients' be visually appealing. A free-standing building INSIDE a garage, could be weird if done wrong.


How big is the garage that this 200sqft structure the will be built inside? How will clients get into the room?

I'd need to measure, but you can fit 4 cars inside it.

I'm a small firearms manufacturer. I'm not overly concerned with the aesthetics honestly. The customers are usually only present for 15-20 minutes for paperwork.

My biggest concern is having people in my actual house ... which my wife wil not agree with.

The customer will enter from the standard garage door (small) on the SW corner. The office will be on the NE side of the garage.

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[nmadole]

Most of December was well below freezing and non stop wind here and i don't think it cost more than about $20 to keep it around 66 every day.

$20 for the month correct?

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[Chilliwack Murray]

Not a scientific measure but the electricity bill for December is up about $20 from last December. Closer to 25 actually.

But using the btu per hour calculation someone posted earlier you could easily convert to kw/h and multiply by your rate.

 

[CNGsaves]

I think I'm going this direction... I'm having a hard time finding one that hooks up to standard thermostat. Any suggestions?

For that small office of 200 sq ft, you could get by with no thermostat at all.

Just get an Oil-Filled heater at Lowes that has 3 heat settings (Low/Med/Hi) along with variable heat at each setting. You can fine tune it all you need. They are 1500 watt so plenty heat for that small space, if you close it up at all and insulate.

Heck I've kept an un-insulated 2 car garage above freezing with one of those oil-filled heaters. I don't recommend it long-term as they pull quite a bit of juice on high.

The hanging natural gas heater would be better suited to keep the entire garage above freezing, whether insulated or not.

 

[Chilliwack Murray]

The reason I suggested the permanent installed baseboards is at 200 sqft it's already a small space and I wouldn't want to have a heater sitting there taking up space.

Also, the newer baseboards create a good flow and mix the air up well enough to have an even temperature which I found an issue sitting at a desk all day with a portable heater.

Plus the two baseboard units and the thermostat cost less than one oil filled portable unit at HD here.

 

[Marctrees]

nmadole - ALL you need to care care of the heat need is a simple cheap portable little plug in heater sold at every Walmart, Big box, hardware store.

Especially living up north, you must have some experience with them.

Totally self contained units, no separate t stat needed.

The ones for $20 are literally just fine.

All the spendier oil filled and such have no advantage in your application.

$20 that's it.

I have been using them as sole source of heat in a full time RV for yearsssss, and now 3 yrs in a 1000' home.

Not as cold as you, but we do get 30 degree nights.

When we lived in MN, as secondary heat occasionally.

Only thing to keep in mind is, they draw about 12 amps, so just plan that into your wiring.

One good idea, is to run a dedicated 120 - 20 ckt to an outlet, use for heater in winter, then little "window" AC in summer.

And your AC will be less than $200.

Smallest unit available mass market, around 5kbtu or so.

NO point in spending more $ on your climate control than this, NONE. Marc