I live in Oregon, which has a reputation for a wet climate. That’s just because most everyone in the state lives in the western 1/3 of it where storms from the ocean dump their load before heading east (mostly). The issue with ground-contact wood (or wood in contact with concrete that is in contact with the ground) is, as was mentioned above, intermittent wetting/drying. Natural Douglas Fir buried completely in the ground will last decades. The same wood completely above ground will last centuries. But a post, even of rot-resistant species, such as cedar, white oak, cyprus, will rot at the ground line. Even wood soaked in creosote or oil. Even in the desert, where I live.
But copper chromium arsinate (CCA) treated wood (the green stuff, not the brown) is virtually impervious to rot, even in the above mentioned horrible scenario (post in ground).
I think your for the superstructure of the shed are delightful, but I question the amount of work for your floor system. If it’s covered with firewood, you’ll only see it for a short time in the spring while you chop and split next winter’s supply. If I were to construct such a structure, I’d consider a traditional pole building, with CCA treated posts (6x6) buried at least 24 inches (65 cm) into the ground. I would make the floor of the shed at least 6 inches (15 cm) above the adjacent area so that surface water runs away instead of laying about by the posts. The concrete paver floor is fine, but I’d lay them on a 4-inch thick layer of sand over a 6-inch layer of compacted gravel. Be sure to remove any organic material (roots, weeds, etc.) first.
I made a shed like that to house my motorcycles about 30 years ago in Portland, Oregon, where it rains at least half the year. I happened to stop by the old place last year, and that shed was still going strong, the new owners storing patio furniture in it.
What you have drawn looks great in SU but it is a bit over engineered. I notice first unconventional floor framing and a foundation that will likely heave under freeze/thaw conditions. Your walls can be greatly simplified with a choice of simpler materials. Engineered roof trusses are okay but for the size of shed you are going to build, however 2x6 rafters (stick framed) will be more than adequate even under heavy snow loads. If you use trusses, your headroom is only as high as the bottom cord member. I would also strongly recommend a wider entrance door, perhaps on the long side of the building or offset on the end so it can swing 180 deg onto the building face. Doing so, the door won’t get torn off in the wind and is out of the way. The added utility of a wide door is well worth increasing up to 48" wide. I would also use a concealed continuous hinge for strength and security. If you set your building on a 4" concrete reinforced pad, it will float. If you do what you have shown in your drawings, the building will lift unevenly from even mild freeze/thaw conditions. I would then recommend you use galvanized metal floor joist framing. Any ground contact even with treated lumber will rot and is subject to damage from rodents, bugs and other environmental elements. Metal Joists are easy to work with and will last. Frame joists at either 16" or 24" o.c. Use metal rim joists to completely enclose for a platform base. Set directly on concrete slab, level with metal shims as req’d. Consider either a window or better yet a skylight for day lighting if you are not going to add artificial light or power. It with be dark inside otherwise. Lastly, I probably would not recommend any roof overhang unless you enclose the underside or add a flat soffit. Open rafters at roof overhangs are good places for birds and wasps to build nests, and they will.
I would strongly urge you to have a look at some conventional storage buildings. TuffShed has been building sheds for a long time. They know what works and what doesn’t. You can use their on-line interactive 3D design tool for ideas. I would then give them a call to discuss. I would do this even if you intend to build DIY. Click on the blue link below.
I am a licensed architect. I get a charge from designing but know almost everything built has already been done over the years by someone else. I don’t mind looking at what others have done for ideas and to see what works and what doesn’t. No reason to re-invent the wheel. There is a TuffShed Dealer in Ontario, Canada so I would talk to them. I am in no way affiliated with this manufacture.
I can’t really see any assembling details and being french makes it hard for me to make understandable critics, but I will try.
In my opinion:
-The poles would need braces to prevent them from twisting.
-the wood foundations would need special attention to avoid dew between what ever material is in contact with. This can be achieved by using a sheet of tarboard. Some species can withstand water, but it must be well ventilated and prevent stagnant water - or - ensure that the wood is permanently immersed. It depends a lot on the materials and the configuration of the places.
Though it’s possible, I would not use wood for foundations. Metal ones are very easy to realise and solve a lot of issues.
Sheds builded like that are usually for drying applications : tobacco, nuts, fruits…
It appear to me that there is one parameter that seems to be missing : mice and other animals that would seep from the ground. It’s quite simple to solve with some galvanized sheets (for the poor) or copper (for the rich) well placed.
Yes, in general, Canada is less damp than the UK - I did live in the UK myself for 16 years and was familiar with damp issues in renos etc.
That looks like a tried and tested system - roughly what I had planned, except we are now not wanting to have enclosed wood storage - best advice so far indicates it is better to keep wood storage in open air.
I was considering multi use for that floor - doubling as a truck repair bay.
The floor would have taken a fair bit of abuse as the floor of a wood shed - could have been lots of heavy chunks of wood dropped on the floor and heavy log splitting equipment.
Currently exploring design concepts at the high end of possibility (there are over 30 projects in various stages of planning at the cottage so it is quite helpful if we can combine a few).
Initial idea was to build smaller than 108 sf to avoid a planning permit - that has been scrapped - so the sky is the limit now.
A few images of a loft bedroom added to a shed with external wood storage -
I am sure that the more ventilation, the better. I have a woodstore that I built into the back of my garage. Just two recesses, open fronted, so no through ventilation. The recesses are quite shallow, but it seems to do the job fine. We have two woodburners to keep happy!
We currently have a half cord of wood stored in a hallway near the back door - so it is warmed up before being used in the fire. The less moldy that wood is the better (through “best practice” initial storage - whatever that may be).
Thanks for the referral - there are missing structural elements from my plans (including soffits) - the basic concept is still too fluid so I tend to leave some of it out temporarily. I do have engineering assistance so all will be dealt with prior to finalization of plans (will also require approval from the local municipality).
Part of this project is about the enjoyment of building it - so I would not look for a fabricator - we may split it up into 2 seasons of work, depending on exactly how much time is available.
Fascinating thread - so common to start using SketchUp and resulting in massive scope creep and over engineered (but very good quality) outcomes!
I thought I would share my approach to a simple wood shed - typical for people in New Zealand who usually do things in a rush and with whatever materials are handy.
Materials:
Cinder blocks as the footings,
sloping ground for natural drainage.
Treated pine joists (wired into blocks) and framing.
Floor made from whatever is laying around - treated plywood is the best/fanciest.
Corrugated steel cladding , wrapping over the roof and overhanging the front, which is mostly open. Snow slides off it.
Paint everything with leftover paint (liberally).
In terms of airflow, there are gaps everywhere and it will all be wonky so no need for “ventilation”.
Sounds terrible, but actually:
Cheap
Easy to build and move and expand, etc.
Can be adapted to whatever you have on hand.
Sustainable because its all off-cuts and reclaimed stuff.
Will last long enough
Looks “rustic” so tourists find it quaint and it blends in with other “rustic” stuff we have.
Thanks @AK_SAM, I appreciate outside the box thinking - or in this case the opposite direction to where the design seems to be heading. We still may just do a fairly simple wood shed - I seem to have lost interest in that a bit.
In some locations I can imagine your shed would be fine.
However, my engineering advisor (former aeronautical engineer) has pointed out wind loading as an issue in open countryside?
Your comment does lead me to another set of parameters. The site has a range of cottage buildings including the original cottage built in 1935 which has a lot of character and reasonable quality of workmanship - a bit of finesse (knotty pine boards and 4x4 structure with some interesting detailing).
DESIGN SPEC (aesthetic / fit / finish)
quality workmanship and materials, consistent with or improving on the existing structures
existing structures are soon to be upgraded to metal roofs, which gives us an opportunity to test that out on this shed - hopefully with the services of a metal roof master craftsman (we could take advantage of this and add other flashing detailing)
as the designer, I am willing to explore more contemporary directions - site location is key here as a little more separation from existing buildings (surrounded by more trees) is likely more suitable with a notable update in design
The scope creep is also significant - as mentioned earlier, there are over 30 projects in various stages of development including solar system upgrades, extra bedrooms, etc.
FUNCTION
I also examine projects from a business development perspective, such as recognizing there is savings of 10’s of 1000’s by combining structures when possible. Short, mid and long term considerations are also evaluated to determine the best value over an extended time period.
If the design were located surrounded by more trees, I would make sure the structure was capable of withstanding considerable tree branch impact (from personal experience, I know how unpleasant that is).
Due to consideration of a site with more trees / closer to the building, the skylight has been moved to a safer orientation.
Also regarding site move, now at a low point - turning an issue into an advantage by raising the low point level slightly above surrounding levels (possible drainage system upgrade).
The well known Canadian building code standard - double hockey sticks rafter system (take note @medeek)
Seriously, the framing is substantially over engineered, but on the plus side, will cope with considerable tree branch impact and make residents feel fairly secure in a storm.
If I were to construct such a structure, I’d consider a traditional pole building, with CCA treated posts (6x6) buried at least 24 inches (65 cm) into the ground. I would make the floor of the shed at least 6 inches (15 cm) above the adjacent area so that surface water runs away instead of laying about by the posts. The concrete paver floor is fine, but I’d lay them on a 4-inch thick layer of sand over a 6-inch layer of compacted gravel. Be sure to remove any organic material (roots, weeds, etc.) first.
