I'm starting to design an insulated shed I want to build later this year. I'm pretty decent with woodworking (not a pro, but I can build things no problem), but I've never build a shed before, so I have a couple of questions. Since I want to use this shed for projects throughout the year, I need to insulate it since I want to heat it in the winter (I'm in Ontario, Canada). I still haven't finalized the size, but it's gonna be either 10x15 feet or 12x12 probably. My first question is to do with the roof ... do I need an attic in such a shed? I know the point of an attic in a house is to keep the roof the same temperature as the outside to prevent snow from melting and refreezing on the roof ... is that the only point of an attic in an insulated building? Do I need this on a smaller roof? If anyone could shed some light on how I should be designing and insulating the roof part of this shed, that will help.
Go for the larger floor space. I think you will find that when you put a table saw in the middle of any space, the saw, and the space you need to use it, gets large. I built a 12x22 space years ago and was surprised at the amount of space I didn't have once the saw went in.
I would insulate the roof and leave the rafters exposed (no ceiling). In a workshop those exposed trusses or joists can provide a lot of good storage for lumber, moulding and other long things. You can sheet parts of it for overhead shelf storage too.
You might want to look into the way wood-frame, metal-sheeted buildings are assembled. The lower framework is pretty much identical to conventional framing. However they use wider truss spacing with longerons that are usually on 2" spacing that adapt well to ceiling bats. For that matter you get pretty good bang for your buck if you build the entire building for metal sheeting and roof. The exterior finish lasts for years without painting and you might find out you can build more floorspace for your money. I helped my son put up a 20x26 garage last year. The two of us had the entire lowere frame done in a day. The next day roof trusses and longerons went up in 5-6 hours with about 2 hours of help from a couple of his buds. He and a couple friends had the entire thing (less garage door) closed in the following weekend. When you start hanging those large sheets of metal it closes in quickly.
That seemd a bit tight to me. Do some sketches with grapha paper and tool placement. Pay close attention to infeed and outfeed space for tools. Think "lanes"; lanes for walking and lanes for stock movement. Example: if you want to rip a 4x8 sheet of plywood the long way on a table saw, you need at least a 16' lane.
Also, multiples of 4 make for efficient use of material. Hint... think12x16 or better.
Storage?
Yes. Freeze/thaw = leaks = water damage.
An alternative is "propa-vents" (I think that's one trade name). They are styrafoam channels that keep insulation away from the roof surface and allow air flow from the soffit vents to the ridge vent. These enable a cool roof surface with an insulated cathedral ceiling.
Harry wrote:My first question is to do with the roof ... do I need an attic in such a shed? I know the point of an attic in a house is to keep the roof the same temperature as the outside to prevent snow from melting and refreezing on the roof ... is that the only point of an attic in an insulated building? Do I need this on a smaller roof? If anyone could shed some
light on how I should be designing and insulating the roof part of this
shed, that will help.
You're right about keeping the roof as close to the outside temp as possible. But if you insulate right up against the roof decking, you've lost the ventilated air space that really does the job of keeping down the ice dams. RonB's right about foreseeing a need to hang/store a _few_ things on those joists. There's a product out there that used to be called "channel bats". Ridgid "U" shaped styrofoam pieces that are laid right up to the decking, between the rafters, then insulation right up under them. Of course, you'll need soffit vents and ridge vent along the entire roof(except the rake overhang). Go for the largest floor space you can. Tom
I just built a shed for the same purpose you stated. I Went with a 12' x 16' because the cost increase wasn't much more than a 12'x12'.
My building is metal exterior, concrete floor, 2x4 stud walls wrapped with poly plastic and R13 insulation. I have a flat 8'1" ceiling with R13 stapled between the rafters, Above that I have a small attic storage space. The attic doesn't need to be insulated let it breath, but you should insulate your work area.
You'll only need 4500 btu of cooling and heating in your shed if you have no windows.
You are correct about a normal heated house, but does this still apply to a detached garage or shed? My garage has no venting at all. The roof is not insulated, but the walls are. I run the heat out there maybe four hours on a weekend day. I may add some insulation on the roof also in the future. but since it is a rather minimal use, I don't see any particular advantage to venting unless I separate the area at the ceiling joists. The other 160 hours a week it is not heated at all.
Looks nice. I didn't think of a metal exterior until RonB mentioned it. Do you mind me asking ... how much did the metal sheeting cost you? I'm assuming it comes in 4x8 sheets?
so Edwin Pawlowski wrote:You are correct about a normal heated house, but does this still apply to a detached garage or shed? My garage has no venting at all. The roof is not insulated, but the walls are. I run the heat out there maybe four hours on a weekend day. I may add some insulation on the roof also in the future. but since it is a rather minimal use, I don't see any particular advantage to venting unless I separate the area at the ceiling joists. The other
160 hours a week it is not heated at all.
Depending on where you live, yes, it can still apply. The OP's in Ontario, Canada. I used to live just north of the southernmost part of Ontario, namely Michigan. If he's gonna heat it in the winter, it'll melt any snow up there, and that'll flow down to the eaves, and refreeze. It's a bad thing, even with all the Ice and Water Shield in the world. You're losing most, if not all of your heat straight up, Ron. Tom
Really, it's about heated vs. not heated. You heat just a little, so you probably run a minimal risk of incurring roof damage. It also has a lot to do with climate. The OP is in Ontario. Sub-zero days (F) are to be expected. I live in that same climate band, you can't just snap on the heater and run out into the shop in 10 minutes. You can warm up the air, but touching 10-degree cast iron is no fun. I'll bet that the OP is going to be doing more than 4 hours a week of heating.
The heat will probably be on for the whole winter, but most of the time it will be to just keep everything a little above freezing ... say 5C (41F), but there will be a couple of days every month that I'll be in there, so it will be closer to 20C for those days (unforutantely woodworking is a hobby ... not a profession :))
If you plan on continuous heating, even if set low, I'd recommend an attic. Insulation, vapor barrier, and drywall. Drywall is cheap. Properly venting insulated cathedral ceilings (you MUST insulate) is a PITA. My grandfather's cathedral ceiling on the cottage wasn't vented and rotted out.
Consider making the walls 9 or 10' instead of 8'. Better for a workshop. Cathedral ceiling with trusses might as well be attic w.r.t. storage.
For storage, ensure you have a good sized hatch.
I suggest a metal roof with a high pitch (ie: 1:1). A bit more expensive than asphalt shingles, but longer lived and less trouble, and the pitch tends to clear the snow automatically. Metal roofing is easy to get. Even the Home/Pro Hardware guys can order it.
On a shed this small, make your own trusses - 2' centers.
For exterior treatment of the walls, if you're not terribly fussy, I'd go with vinyl siding. The shed I built did, and it was easy and inexpensive, and pretty durable.
Think windows, lots of 'em. Make your own. Get the SO to make drapes out of "remaindered" towels ;-)
At least match building code for the floor joist size/spacing.
Thanks for the suggestions. This is going in my backyard, so the wife has to approve of the look. Anything overly tall will look a little out of place and overpower the whole backyard, so there goes the really high walls and 1:1 pitched roof ... however, as long as this shed is like a garage inside, I will be more than happy (the house has no garage, hence me building this shed)
I'm guessing you're suggesting windows to allow light to come in ... is this really important? It will contribute somewhat to heat loss, expense, and complicate the construction, so I was hoping to not have any windows, just double doors at one end of the shed.
As for the floor I was planning on using 2x6 PT lumber, supported on 12 or so concrete blocks ... I still have to finalize all of this and actually read up on how to do the foundation, etc ...
Since you are at the design phase, head on over to alt.solar.thermal and start considering passive solar design. you might be able to greatly reduce the cost of heating this outbuilding.
Chances are that it will already do that. Most people can't hide a 12x15 shed regardless of what the roof looks like.
[We can, but that's another story ;-)]
Lighting is _really_ important in a workshop. Painting the inside white helps too.
My workshop (the garage) has commercially made thermopane units, which aren't _too_ bad. They're relatively small. 3 of them, only 16" wide, perhaps 40" tall, in an oversized double garage. I wish I had more of them. White painted walls and LOTS of lighting makes up for it.
The shed, which isn't heated, has home made windows (PT 1x6 frames (fence boards), "left over" single pane glass). It doesn't complicate the structure because I designed the lites to fit _between_ the studs (24 OC), and notched the horizontal frame components to fit over the studs. [Didn't even have to cut the glass.]
As it worked out, I was able to put in triple section windows, almost 6 feet wide, without having to cut any studs nor install headers. Frames are "foamed" in, and are air tight.
With full heating, you'd probably be best looking at a few strategically placed tall/narrow (stud space width) thermopane units. It'd be a lot cheaper to make the frames yourself around custom-made thermopanes than to buy pre-made.
You'll probably find that sheds with more than 100 square feet of space require "real" poured footings, not cinder blocks by the OBC. [Each municipality gets to decide at which size the OBC kicks in.]
If you're going to put power in, they're probably going to _insist_ on you following the OBC.
When I reconstructed my shed, I was only able to "stay" with cinderblocks because it was an existing shed. Secondly, the idjit who originally built it used 2x6 24" OC, with a 12 foot span, and to stabilize the floor, placed blocks under the joist mid-points.
It _might_ have been relatively steady to begin with, but after all of these cinder blocks _rolled_, it became a trampoline.
DON'T repeat that goof. You'll regret it.
In order to fix it, I had to jack up the shed, put in 12x12 (I wish they were larger) concrete pads under the corners and ring joist midpoints, on top of a 4" bed of gravel[+]. Then, instead of the stupid cinder blocks under the joist midpoints, slung in a doubled up 2x8" beam underneath, end points supported by the ring joist midpoint blocks.
Once all that was done and releveled, was able to rebuild the upper part.
[Original single-pitch roof sheared off (2x4 12' span!!!!), replaced with trusses, metal roof, windows installed, stupid curve top door moved and replaced with a proper square one, painted white inside, offcut vinyl floor, vinyl siding, and a cute little deck ;-) It's a work of art ;-)]
[+] 24x24 Patio slabs would have been ideal, but the ones available aren't good enough (I'd have wanted 2" thick and/or rebar)
Good suggestion here that made me remember a good, simple planning tool. Take a look at the Grizzly web site. They have a very simple Visio type of tool that allows you to lay out the shape of your shop and then place scaled power tool images in the shop for planning purposes. It is very simple to use. Obviously they provide graphics of Grizzly tools but "tools is tools" so long as you select models that are in your general planning range. You can jump back to their site for general info and sizes if needed. Try the link below and if it doesn't work go directly to
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It links directly from their home page ("Build your dream shop....").
If you are going to build larger cases that require you to cut plywood or 8" lumber it is a good idea to plan for an 7'-8' radius around the table saw blade for movement of stock. We don't always get this but it is a nice goal.
Seen quite a few good tips so far but haven't seen this:
Rethink your sizing so that each side is divisible by 16" to prevent waste and the hassle of having a fraction of a 16" stud space at the end of the wall -DAMHIKT
Think about it. Doesn't it seem easier to build and cut lumber for a
12'x12' shed than a 10'x10'?
As for size, be guided more by the allowable room in which to build than by the cost today. After your raise next year that extra 100 sq' or 150 sq' will make you smile
Chris's advice is good, I'd also add at least one skylight. The more natural light you have, the better -- things go so much better when you can see what you are doing.
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