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Firewood shed, dimensioning of girders and joists

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I am going to build a 7'x16' firewood shed to hold about 6 cords.
I am using rough sawn spruce lumber throughout.

For the floor I am planning to use two 16' long 8"x8" laminated beams spaced 5' o.c..
Each beam will rest on two 12"x12" post spaced 13' o.c.
The beams will be cantilevered 12" at each end.
The span of the beams between the posts is 12'.

I will cantilever the joist 8" on each side.
The span of the joists between the beam will be 4'4".
I am planning to use 2"x6" joists spaced 16" o.c..

The floor will be made out of 1"x4".

I am going to stack the firewood 7' in height.
I have estimated a floor load of 200lbs/sqft.

Is my dimensioning OK?
Will this platform as designed hold the weight of the wood?


A full cord of firewood (post #207116, reply #1 of 9)

A full cord of firewood stacks up tightly approximately 4' x 4' x 8'. Green, it can weigh close to 1 1/2 tons depending on species. I cross stack mine loosely so air can circulate, I use about 4 full cord. It fills a space 12' x 12' stacked about 6' - 7' high. If you are talking face cords 2' x 4' x 8' tight, you'll barely fit 7' x 16' . What lengths do you use? You may want to think about the size and how you want to stack it, plus some extra room for leftovers. You didn't say if you were building walls or a roof. I'm going to build a 12' x 20' garden shed. My floor frame will be 2" x 8" pressure treated joists 16" OC doubled perimeter set on concrete pads on the four corners and two intermediate pads on the 20' lengths. I'll jack and shim it over the years as necessary. Anything over bare ground around here will be subject to microbes and other bugs, likely a skunk or woodchuck will dig a home under, the PT lumber won't be effected for a much longer time than spruce. Mine won't be for firewood, it's for motorcycles, garden tractor, tools etc.

Beat it to fit / Paint it to match

My live load of 200 lbs per (post #207116, reply #5 of 9)

My live load of 200 lbs per sqft is based on 3700 lbs per cord. I already have a shed where I fit ±5 cords stacked 7' high on 12'x8'. I am building a new one to have a year's firewood in advance. I use 21" lengths. It's a shed but my question was only about the sizing of girders and joists. I have solved the question now. My girders will be 3x 2"x8" (rough sawn) 16' long laminated girders set on 4x 12" round posts set 10' apart. The building will overhang the posts by 3' each side. The whole platform is high enough above the ground that I can go under. No animal can hide under it. The spruce is far away from the earth and well ventilated. 2"x6" joists 16" o.c. are adequate for the load.

Sounds like alot of work for a wood shed (post #207116, reply #2 of 9)

I find discarded pallets.  They are nice as they are "open" and air circulates under them.  The little bits of bark and stuff that falls off teh wood falls through the slates in the pallets.  The last along time.  But in 15 years replace them.  And yes some of them sag under teh weight of the wood, but who cares.  Then again, you might be one of those who love solid buildings for everything.  I do understand this as I am that way for many many things, but my wood shed is just a wood shed. 

Too each their own, and jsut a thought.


Vapor Barrier (post #207116, reply #3 of 9)

I suppose a vapor barrier under the pallets or even a floor for that matter might be a good idea if you live in a wet area with high ground water and thus soil moist.  Wish I have thought of that before.  Then again I have not notice any ill effects of not having it.


+1 for using old (post #207116, reply #4 of 9)

+1 for using old pallets.

The OP descriptin is a Taj Mahal of woodsheds, i guess fine if ya got lotsa $$ to spend or can get 12x12 free. 

You haven't described your (post #207116, reply #6 of 9)

You haven't described your wall design. Will it let air through? I've found that to be an important issue.

With mine I used rough sawn 2X6 fir with 4" of space between. Seems to work well.

firewood shed walls (post #207116, reply #7 of 9)

Scott wrote:

You haven't described your wall design. Will it let air through? I've found that to be an important issue.

With mine I used rough sawn 2X6 fir with 4" of space between. Seems to work well.

Rough sawn pine 1"x4" no space because of the snow drifting into the building but the two 7'wide ends will stay open with big doors in summer and then closed for the winter. In drying out the 1x4s give enough space for a good ventilation without letting much snow in.

No sides (post #207116, reply #8 of 9)

I too can have some problems with snow blowing into the shed, but it is cold outside and it does not melt right away so the wood stays dry.  And if the shed is not full then the snow just falls on the nearby pallets.  If the shed is full I might through a small tarp on the side most pron to snow.

I like not having sides on the shed.  You get maximum air flow.  I often cut green wood as part of logging or thinning projects and some of it goes straight into the shed.  If you stack green wood in a closed shed fungus grows on the cut ends, not good.  I also like to be able to stack wood on one end of the shed one year and draw dry wood for the winter out of the other end,  Then reverse the process the next year.  And some times I draw wood out of the middle of the shed.  Makes things easy.  Easy to load the shed, easy to get your wood out.

Maybe one wall on the side of the prevailing wind?


Careful with 1 X 4 (post #207116, reply #9 of 9)

Careful with 1 X 4 !!!!

Don't make the same mistake as me. I started with 1 X 6 and learned that by the time the shed was stacked full the walls looked like Dizzy Gillespie's cheeks. Then I had to redo them with 2X and they're fine.

I'd also rethink the buisness about gaps between boards. By the time Winter hits, a bit of snow blowing in shouldn't hurt anything. The wood will already be dry and frozen so won't take on much moisture.

But during the warm months, when you really want moisture to escape, it's important to allow circulation.

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