Heating a shed

[ray66v]

If your going to store a car in there, and want it to stay in nice condition, you don't want to use an unvented heater, especially LP. There will be a lot of moisture, with no where to go.

I painted the floor in my insulated, and finished, 2 car attached garage, last fall. It was getting very cold at night, so I put a 1500 watt heater out there, to help keep the temperature up, so the paint would cure properly. To my surprise, the heater was eventually able to maintain 75 degrees in the 450 sq. ft. empty garage. It was not even running all the time.

Remember, most of the area of the inside of this building, will be filled with the car. So a 1500 watt electric heater can easily keep it from freezing, if you properly insulate the building.

 

[mbrule]

Thanks everyone, I think I am going to pick up 2 -3000 Watts of electric baseboard and try it this winter, for effectiveness and cost to run. It looks like a couple of hundred bucks will install it, cheaper if I can find used. konwing that with such a small investment, if it is expensive to run, I can look at a vented natural gas or propane heater later.

My biggest issue now is insulating the floor, I am planning on adding a 3/4" layer of tongue and groove OSB to stiffen the floor, it is presently 3/4" PT Plywood over PT 2x4 on 12" centers, which are on PT 4x4s the 4x4s are on crushed stone so there is a 4" air gap under the shed.

I am contemplating may be an inch of some sort of foam insulation under the OSB, with 1" boards where the cars tire will run, what do you guys think? Any other suggestions.

 

[kidr]

Does this mean that I could not use electric baseboard?

Right now that is what I am favoring, because install cast is very low and if it ends up being too expensive, I could consider another source, and keep the electric for use when I am out there and want to warm it quickly.

By law in some states you may not put a heater below 18 inches in a garage. Think fumes ,spark or flame , explosion. gasoline fumes are heavy and sit on the floor. Do as you like , but you were warned. Hey , check with your insurance co. also.See what they say.

 

[mbrule]

By law in some states you may not put a heater below 18 inches in a garage. Think fumes ,spark or flame , explosion. gasoline fumes are heavy and sit on the floor. Do as you like , but you were warned. Hey , check with your insurance co. also.See what they say.

Does that apply even to electric heat? No spark of flame there right, just a heating element. I don't want to do the wrong thing, but am attracted to the cost of baseboard. No questions for the insurance company, I do not want to attract their attention....

 

[ray66v]

Plywood will stiffen the floor more than OSB.

 

[nap61]

mbrule,
You don't want to get the insurance co's attention? If a fire happens, you will get their attention big time. They will investigate and if you did anything that was excluded in the policy, they won't pay. It will be your nickel.

Norm

 

[Carl Bert]

Forget about the ventless gas heaters. As a plumber friend once said, "they are a slow death" As far as electric heat, I don't know about your area but electicity up here is very costly, especially if you are heating an area with as many drafts as a poorly insulated shed. Your best bet is to have a professional run a gas line from the house, and use a ceiling mounted burner with an electric fan. The most efficient and safest by far. With a properly sized unit, you will be able to go from 30 to 65 in a matter of 10 minutes.

Are your walls 2x4 or 2x6 framing? That is going to make quite a bit of difference in the R-value you will be able to achieve. Also use a vapor barrier as it will really help with the drafts and of course moisture. The floor is what really worries me. You are going to park a 3 to 4000 lb car on a 2x4 framed floor? Yes 12" oc is better then 16", the question I have is, how far apart are the 4x4s spaced?

Just a few things to think about. Good luck. :thumbsup:

 

[mbrule]

Forget about the ventless gas heaters. As a plumber friend once said, "they are a slow death" As far as electric heat, I don't know about your area but electicity up here is very costly, especially if you are heating an area with as many drafts as a poorly insulated shed. Your best bet is to have a professional run a gas line from the house, and use a ceiling mounted burner with an electric fan. The most efficient and safest by far. With a properly sized unit, you will be able to go from 30 to 65 in a matter of 10 minutes.

Are your walls 2x4 or 2x6 framing? That is going to make quite a bit of difference in the R-value you will be able to achieve. Also use a vapor barrier as it will really help with the drafts and of course moisture. The floor is what really worries me. You are going to park a 3 to 4000 lb car on a 2x4 framed floor? Yes 12" oc is better then 16", the question I have is, how far apart are the 4x4s spaced?

Just a few things to think about. Good luck. :thumbsup:

Th floor will support the car as is the 2x4s are 12" on center and there is five 4x4s under them across 12". It is a prebuilt shed designed to store a car. I just want to stengthen it some and insulate it. It is not a poorly built drafty shed, it is actually surprisingly tight except for the doors, which I am going to improve.

The car is actually almost 5000 lbs! 71 Delta 88 Convertible.

Thanks for all the advise!!

 

[radioman]

perhaps you could either use spray foam to spray underneath the floor if you can get the spray company to reach to it. If not, perhaps a closed cell foam board in 4by8 sheets laid on floor staggering the joints and put new 3/4 inch plywood on top and screw everything down would help to keep things warm on the floor.

 

[heehaw]

i've used the unvented gas heaters for about 20 years now: i keep a humidastat(misspelled) in a couple rooms: and have NEVER seen a big rise in humidity: but we have high humidity in Arkansas anyway?? but i have never had a single problem with them: i would stay away from the ones called "blue flame" because in my experience, they do not heat anywhere near as well as the infared ones: adding a fan to move the air around helps a lot, but all of the ones i use have sensors to shut them off if there are any issues at all: which have been 0. as for the price of propane: if you install a tank, and have it filled when companies have their "pre-buy" period: it can be really really close to the price of natural gas: a couple years ago, it was actually cheaper.
heehaw

 

[ray66v]

i've used the unvented gas heaters for about 20 years now: i keep a humidastat(misspelled) in a couple rooms: and have NEVER seen a big rise in humidity:

That could be for a lot of reasons, like the temperature you set, the amount of air leakage from outside, (including number of times the door is opened), climate, and the big one, the size of the area.

I would suspect, your home has enough air leakage, through tiny leaks like in doors, windows, fireplace, and from opening the door, that the moisture is not accumulating.

I have seen water literally condensing on the walls and ceiling in a 2 car garage, that was using an unvented catalytic heater.

We know gas, particularly propane, is loaded with moisture, and with an unvented unit, the moisture has no where else to go, but into the area your heating.

If you sealed this small barn with an unvented heater inside, it would be detrimental to the car.

He would be much better off not heating it at all.

 

[mbrule]

If I use propane, I will likely use a vented model. Given that I can vent easily enough. I appreciate the input.

 

[Roger 1088]

Hi, I have a wooden garden shed 3m x 4m, that is well built, no draughts, but not insulated. In the winter we get well below freezing. I'm thinking of installing electric tubular heating. Just to keep the plants from freezing. How many watts will I need?

Many thanks

Roger

 

[ray66v]

Hi, I have a wooden garden shed 3m x 4m, that is well built, no draughts, but not insulated. In the winter we get well below freezing. I'm thinking of installing electric tubular heating. Just to keep the plants from freezing. How many watts will I need?

Many thanks

Roger

Depends on your climate, and how much wind there is, whether your going to open the door in the cold weather, or not.

My guess is 2000 watts could keep it 45 degrees. And it is potentially going to run a lot of the time.

You would be much better off insulating it, if your going to heat it.

The difference in the amount of wattage would be considerable.

In contrast, you can heat a small area with a light bulb, if you insulate it well enough.

 

[Roger 1088]

Thanks Ray for such a quick reply.

The truth is that until last winter we never bothered. Temperature never got worse than a couple of degrees below (Celsius) so there was no need. In the winter we just use it as safe haven for plants. No traffic in and out.

Then the surprise in December, heavy snow followed by deep freezing over the following months. We jumped down to minus 17 (Celsius) . This was partly the effect of the Iceland Volcano so I hope it won't be so bad this year. Just want to be on the safe side.

By the way this is "sunny" Italy.

Thanks again

Roger

 

[ray66v]

Ciao, What part of Italy?

In that case, I would just insulate the building, and not worry about heating it. It should not freeze in there, in that kind of climate.

 

[sweettractors]

To be safe with the plants, A thermostat controlled electric 1500 watt heater would do the trick. Ken Sweet