Heating My 24x35 Shop

[raneyday]

Hi All,

I have a 24x35 shop. It is stick framed with siding, concrete floor, open rafters, two small windows, and it is not insulated. I'm in SW Missouri and we have four seasons. I'm looking for some advice about late fall and early spring warmth in my shop. I'm not looking for 72* in the dead of winter (when sub-zero temps happen), but would like to be comfortable working in the shop when it's 35-40* outside. I don't mind working in a sweatshirt and/or light jacket, so would like to know if it's reasonable to expect to warm the shop up to 60* plus and maintain it while I'm put there working. I just want to be able to work on my cars when they inevitably have an issue when it's cold...and finish my tractor restoration(s)!

I am thinking about one or two 240v/5,000w or even 7,500w ceiling mounted heaters.

I have 100 amp sub in the shop, and am capable of running additional 240v circuits. Other big amp draws in the shop are a 5hp/80gal IR compressor, and a Hobart Stickmate 210i (40 amp draw at max output), oh...and the beer fridge! I'm thinking the draw of the compressor, welder, and heaters can be managed so they aren't hitting at the same time. The fridge stays on!

Sorry this is long, but wanted you to have details. Appreciate any feedback you might have.

Thanks!

 

[jvitez]

I wouldn't use electric for what you have, it won't heat well and be expensive. I'd get a big kerosene or propane torpedo heater or a big "top hat" type propane convection heater, big like 75k-125k btu. Heating an uninsulated, ventilated space just doesn't work well in my personal experience. I'm assuming your roof is ventilated.

If you want to do it at least a little bit properly, then drywall the ceiling and blow in cellulose or fibreglass insulation. You can leave the walls for now. It would make a huge difference in heat loss, allowing you to use electric. You'd need minimum 7500W, better would be 10kW. Now if you insulated the walls too you could get away with one 5000W electric heater.

 

[raneyday]

The roof is not ventilated. I'm pretty sure the previous owner built the shop from a kit, or paid someone to do it. He poured the floor on his own and had several blow outs in his framing, so I have a floor with some pretty good waves in it. This means that there are places where the bases of the side walls don't actually touch the floor. It's been shored up by a contractor I really trust. He says it will be fine for what I'm using it for now, but drywall is a no no.

I have thought about a torpedo heater, but have two concerns:

1) Floor Space
2) Wouldn't I have to leave the windows open?

 

[Lelandwelds]

I dont know how you stand it. It was 80°F here a week ago. I bet you get slushy white stuff falling from the sky, too.

Welcome. I hope the yankees recommend overhead radiant . That one is fascinating.

Off topic, but, is the size killing you? I am planning a 24 x 40 .

 

[Lelandwelds]

The roof is not ventilated. I'm pretty sure the previous owner built the shop from a kit, or paid someone to do it. He poured the floor on his own and had several blow outs in his framing, so I have a floor with some pretty good waves in it. This means that there are places where the bases of the side walls don't actually touch the floor. It's been shored up by a contractor I really trust. He says it will be fine for what I'm using it for now, but drywall is a no no.

I have thought about a torpedo heater, but have two concerns:

1) Floor Space
2) Wouldn't I have to leave the windows open?

You're describing a shop with lots of ventilation. Adding insulation and dry wall is possible. A laser, some carefully spaced blocking, and a foot operated teater totter make it manageable. The ceiling cries for a store-bought or homemade panel lift.

An actual drywall screwgun is priceless.

 

[Patrobot]

That sounds a lot like our shop, I have to agree that the lack of insulation in our ceiling (open rafters) hurts us in the winter. In the summer the very well insulated 6" walls keep the place cool and dry for a day after turning off the heat pump which is what we use for primary heating & cooling. I had planned to use a propane wall heater but after using a propane torpedo to just take the chill out of the air I could tell the air had been significantly depleted of oxygen. We tried a 240v 5k watt construction heater but it was pitiful. So I'm running an oil filled heater 3-4 days a week to keep the interior from getting to cold between uses and flicking on the heat pump if I plan on using the shop. So far I get heat out of this pump in the teens and it's very quiet.

 

[BillK]

Without insulation you are going to have a hard time with it. You will need something that puts out a LOT of heat.

 

[raneyday]

You're describing a shop with lots of ventilation. Adding insulation and dry wall is possible. A laser, some carefully spaced blocking, and a foot operated teater totter make it manageable. The ceiling cries for a store-bought or homemade panel lift.

An actual drywall screwgun is priceless.

I am capable of hanging the drywall, just have been told that the structure won't support it.

 

[raneyday]

You're describing a shop with lots of ventilation. Adding insulation and dry wall is possible. A laser, some carefully spaced blocking, and a foot operated teater totter make it manageable. The ceiling cries for a store-bought or homemade panel lift.

An actual drywall screwgun is priceless.

I dont know how you stand it. It was 80°F here a week ago. I bet you get slushy white stuff falling from the sky, too.

Welcome. I hope the yankees recommend overhead radiant . That one is fascinating.

Off topic, but, is the size killing you? I am planning a 24 x 40 .

Yeah, it's tough. I spent 6 years in Fort Worth and 7 in San Antonio, so I've been where you are. We love the four seasons, but can't do much in Dec/Jan. Of course, the same was true in SA in June/July.

I don't think anyone ever said, "My shop is too big". Having said that, the size is OK for me, but I'd like to have about 10' more each way. My shop doubles as a work space and a storage space. Back wall is custom shelving I built to store camping gear, my fifth wheel hitch, chainsaws, etc. I store my little JD lawn mower and my '49 8N. Stil have room to pull a one ton truck or a suburban in with plenty of room to work on it. But between my sand blaster, 60" tool box, parts washer, workbench, beer fridge, shelving, etc...I'm about out of floor space. Not sure where I'm going to put the welding table...

One advantage of the open rafters is scrap lumber and garden tools get stored up there, so that saves me some space. You just have to be diligent about what goes in and what STAYS in the space. I complain about it some times, but it's a whole lot more than I thought I would have.

 

[raneyday]

That sounds a lot like our shop, I have to agree that the lack of insulation in our ceiling (open rafters) hurts us in the winter. In the summer the very well insulated 6" walls keep the place cool and dry for a day after turning off the heat pump which is what we use for primary heating & cooling. I had planned to use a propane wall heater but after using a propane torpedo to just take the chill out of the air I could tell the air had been significantly depleted of oxygen. We tried a 240v 5k watt construction heater but it was pitiful. So I'm running an oil filled heater 3-4 days a week to keep the interior from getting to cold between uses and flicking on the heat pump if I plan on using the shop. So far I get heat out of this pump in the teens and it's very quiet.

You guys aren't saying what I want to hear . But it's what I expected, especially regarding the torpedo heater. Have no problem pointing one of those in my general direction when working outside. Have no interest in suffocating inside!

I've thought about insulation in the walls, but I use the open space to hang a lot of stuff and keep it up off the floor. I imagine I could still solve that if I put insulation in the walls. Maybe a radiant barrier on the ceiling? Maybe just leave it be and use the winter months for my "inside" projects.

 

[jvitez]

OP: where are you located? Do you need vapour barrier in your climate zone? If so, you try installing vapour barrier alone on the ceiling as it would reduce the volume of air needed to be heated. But, if the roof isn't ventilated then you could have serious condensation under the roof sheathing.

How much are you willing to spend? Spray foaming the underside of the roof sheathing would make a huge difference in heat loss but it's expensive.

You're best bet is is high output kerosene or propane heater, use only when you're out there. To do it properly sounds like a lot of work.

 

[jvitez]

Didn't see your last post. Forget about doing anything with the rafters then.

Actually, your best bet be may be just to heat up where you're working and not try to heat the whole shop. How about this?

http://www.mrheater.com/35-000-btu-portable-radiant-heater.html

I have one, use it in my 1800 sq ft garage, 12 ft ceilings, with insulated walls but uninsulated, ventilated ceiling. It does nothing to heat the space, but if I work in front of it's better than nothing.

I've also got one of these:

http://www.mrheater.com/portable-buddy-heater.html

It's great for hunting, but only useful to warm my hands in the garage. I'm in Canuck Siberia though, forecast says -25°C Christmas day.

 

[Lelandwelds]

I am capable of hanging the drywall, just have been told that the structure won't support it.

Sorry, your photos are missing. If it will support a roof, wind loads, and lumber in the trusses, I would have guessed drywall was OK. They say that wood stuff grows on trees. It is some kind of strange building material.

Yeah, it's tough. I spent 7 years in San Antonio

I don't think anyone ever said, "My shop is too big". Having said that, the size is OK for me, but I'd like to have about 10' more each way. My shop doubles as a work space and a storage space. Back wall is custom shelving I built to store camping gear, my fifth wheel hitch, chainsaws, etc. I store my little JD lawn mower and my '49 8N. Stil have room to pull a one ton truck or a suburban in with plenty of room to work on it. But between my sand blaster, 60" tool box, parts washer, workbench, beer fridge, shelving, etc...I'm about out of floor space. Not sure where I'm going to put the welding table...

.

I get lost every time I cross the SA city limits sign.

I think you are saying, without the "storage" part of the equation, your shop size is pretty damn good?

You guys aren't saying what I want to hear . But it's what I expected, especially regarding the torpedo heater. Have no problem pointing one of those in my general direction when working outside. Have no interest in suffocating inside!

I've thought about insulation in the walls, but I use the open space to hang a lot of stuff and keep it up off the floor. I imagine I could still solve that if I put insulation in the walls. Maybe a radiant barrier on the ceiling? Maybe just leave it be and use the winter months for my "inside" projects.

Building leak like crazy. Do you have R or U panel? Overhead doors? Want a good laugh? Stick a blower door on it.

Radiant barrier with a air space makes a huge difference in the summer. You have installed a giant heat radiator to keep the sun and rain out.

I knew a scrapper who had a kerosene torpedo firing into a spaced stack of cylinder heads. Worked better than it sounds. There is a style of Finnish or Russian masonry heaters designed that way. Kinda hard to move though.

 

[BillK]

Have no interest in suffocating inside!

.

I dont think you will have to worry about that in a big, open, uninsulated building like yours.

 

[raneyday]

I think you are saying, without the "storage" part of the equation, your shop size is pretty damn good?

Indeed it would be for what I use it for - auto maintenance (next shop will be taller with a lift), tractor restoration, antique machinery restoration, and furniture restoration. I paint outside - don't judge. I have plenty of space with the storage stuff. Only challenge is permanent tool placement i.e floor space. I think my next addition will be a big shed to move the push mower, pressure washer, etc, into. Those things really eat up floor space for the limited use they get.

 

[raneyday]

I dont think you will have to worry about that in a big, open, uninsulated building like yours.

Still makes me nervous. Thought about a double barrel stove, but don't want to give the the floor space.

 

[Lelandwelds]

Still makes me nervous. Thought about a double barrel stove, but don't want to give the the floor space.

I think one of the vented radiant heaters like this would be the hot ticket. They have different reflector choices for ceiling height.

 

[trashmanssd]

Didn't see your last post. Forget about doing anything with the rafters then.

Actually, your best bet be may be just to heat up where you're working and not try to heat the whole shop. How about this?

http://www.mrheater.com/35-000-btu-portable-radiant-heater.html

I have one, use it in my 1800 sq ft garage, 12 ft ceilings, with insulated walls but uninsulated, ventilated ceiling. It does nothing to heat the space, but if I work in front of it's better than nothing.

I've also got one of these:

http://www.mrheater.com/portable-buddy-heater.html


It's great for hunting, but only useful to warm my hands in the garage. I'm in Canuck Siberia though, forecast says -25°C Christmas day.

I agree with this, with your shop and the amount of heat loss you will get I say heat your self or your direct area with radiant infrared heating.

Link from Northern Tool with 40 good reviews of the one he suggested

https://www.northerntool.com/shop/tools/product_200178574_200178574?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Heaters,%20Stoves%20%2B%20Fireplaces%20>%20Propane%20Heaters%20>%20Propane%20Construction%20Heaters&utm_campaign=Mr.%20Heater&utm_content=174335&gclid=CjwKCAiAsejRBRB3EiwAZft7sP3PBYmnZlCLYXYM8ZJmKcGWrnfxC3aM618Q9zdptkkzns36CkpztBoC8GYQAvD_BwE

 

[Patrobot]

We toyed with the idea of temporarily hanging large sheets of cheap poly from the bottom of the trusses to keep the heat from filling the peak of the roof. We also considered installing rigid foam insulation between the trusses on the backside of the roof decking. We have a lift so sheet rocking is not an option for us either.