Building a Shed under a Deck

How to build a shed under a deck. The following youtube video covers some important factors to consider when building such a deck.

I used 3dsmax to model my deck and shed.
I recently converted the 3D deck & shed plans into sketchup so that others can benefit.

Feel free to download the sketchup file and use Google Sketchup to view, measure, and modify my shed/deck plan for your own use.

FREE Google Sketchup Plans for my deck and shed.

Back in 2001 my new home needed a deck. I designed a deck that was small and simple.
The 2 posts and single beam were massive screwed and glued planks.
I am proud of the fact that I single handedly designed and built my deck.
It was a lot of fun figuring out how to lift that heavy, wet, pressure-treated beam onto the posts all by myself.
The posts weren’t small either, when you consider they are almost 6 feet underground!

Overkill should be my new middle name.

Designing my deck with only 2 posts, allowed plenty of space for a shed.
The first stage of building my shed was to build the roof within the joists of the deck.
This stage took a long time and a bunch of thought.
I decided to build an angled trough system with curved sheets of aluminum flashing.

Here you can see the underside and the gradual slope for rain runoff.

This was an incredibly tedious process. I used a large quantity of industrial caulk to seal the aluminum to the joists.
This tedium will be worth it because it maximizes my sheds headroom.
I’m 6′ 3″ and there is just 1″ of headroom from the joists.

The next time I need to cut bricks… I’ll get a diamond blade.
It sure took me a long time to cut them with an abrasive disc.

The shed roof survived the winter and showed no leaks. Now the next stage. I had a concrete pad poured. I decided to put my shed entry on the left side of the deck, so I had to dig the hillside down and create a patio for the doorway. This summer was incredibly hot and moving my sprinkler lines was no fun.

It’s took an eternity to figure out how to build the walls. I had to leave a gap between the walls and the deck. I expected the concrete to heave in the winter.

My excitement is building and I can see the light at the end of the tunnel!

The doorway is short and non-standard. I had to build a custom double door.
Another month or so would pass before I could finish my custom shed doors, but I’m happy with the result. I wanted my shed to look as nice as I could make it… so I wrapped it in matching vinyl siding. My trailer-lift project may have been my most gratifying project, but my shed has been the most useful. Good thing I allowed space for the concrete to heave in winter… because it did just that!

YAAA! My garage is clean and useable again.

Comments

  1. July 4th, 2014 at 05:24 | #1

    Building a storage shed under a deck is one tough job. Storage Sheds need to be built very carefully. For building a shed under a deck, you can screw sheets of corrugated metal or fibreglass roofing to the furring strips. This acts as a roof over the storage area. You can cut and install wood lattice around the deck foundation, so as to hide the storage area from view. For this purpose thicker lattice should be used, as it holds up better than the thinner lattice.

  2. Ethan
    September 2nd, 2014 at 08:37 | #2

    Did u used house wrap?

  3. September 2nd, 2014 at 10:08 | #3

    @Ethan, I didn’t use house wrap, but in hindsight it may have been a good idea. I’ve seen no signs of mold or rot and I don’t think there will be, since I was thorough with the vinyl siding installation. The shed still looks great, but my doors need refinishing now.

  4. Ethan
    September 2nd, 2014 at 12:53 | #4

    Thx, love ur shed. Buliding the same one right now hehe thank you for sharing. Just done with the roof, now working on the framing.

  5. February 6th, 2015 at 21:06 | #5

    Dear Alan,

    I have been surfing the internet while the snow flies and I enjoyed the blog.

    For longevity did you use an ice and water shield or rubber under the aluminum to protect the OSB? I am a deck and porch contractor in Massachusetts and our climate is similar.

    And since you mentioned it to another poster have you noticed any heaving of the concrete?

  6. February 6th, 2015 at 22:37 | #6

    @Boston Deck, Thanks… I didn’t use anything between the aluminum and the OSB, but there are no signs of any problems. It might be a good idea, but in my case everything looks good. The concrete heaves every winter … at least 1/2 inch and usually more. Since I designed a space between my shed walls and the deck… there has been no problem. I hope to refinish the doors in the spring and I will try to shoot some new HD video of the condition of the shed. Except for the doors… it looks as good as the day it was built.

  7. Scott
    February 12th, 2015 at 12:31 | #7

    I really appreciate that you shared this project. I’m going to build it this spring. I’m a Minnesotan exiled to Indiana for work purposes. One question, what did you use on the exterior of the rear shed wall?

  8. February 12th, 2015 at 13:57 | #8

    @Scott The inside wall next to the house is actually bare plywood. It was built tight enough to the house and the deck shielded it from the elements. The vinyl siding corners of the shed completely the obscure the ability to see the plywood.

  9. Brenda
    March 20th, 2015 at 09:09 | #9

    Thank you for the great blog! I too live in MI, a suburb west of Grand Rapids and have a similar home built in 2001 (bi-level). I’m considering this task but I was wondering if you had to pull any permits from your city/township to build the shed and if there were footage requirements for a stand alone structure? I think I read on my township website that it has to be so many feet from my home.

  10. JT
    April 10th, 2015 at 12:40 | #10

    Alan,
    This has been an inspiration to me, just had concrete done for the floor. I am working with a ~600sq ft deck (12′x40′) with attached gazebo (12′x12′) which I am using half the space for a shop/shed and the other half for a patio. I am in the northern part of Virginia, and will be back to post some photos once the rainescape system is done before the walls go up. Heaving is still a concern even for Virginia or so I think, so I am still working on that solution.

    Many many thanks again for doing this I can’t imagine how many homeowners you have inspired by the articulate details provided here.

  11. Percy
    April 19th, 2015 at 13:03 | #11

    Great blog!. Was a permit required? I am in a non-HOA area so I do not think I would need a permit. I am also in Northern VA. I am currently looking for someone to build me one like this so I can park the motorcycles during the winter clearing the garage for the cars!. If anyone know a good builder for an estimate please let me know.

  12. amy
    May 5th, 2015 at 11:59 | #12

    I am interest to know how the aluminum flashing was attached to the house so there would be no leaking. We have an existing deck that we want to drain but there is no flashing to there now. We want to make sure and get all the rain but are not sure how to get the trough attached to the wall w/o leaks

  13. May 12th, 2015 at 01:02 | #13

    I’ve many question over the years about why I built my shed unattached as I did. Here is a great website reference for why frost/ice heaving is so powerful and damaging… http://www.structuretech1.com/2013/06/frost-heave-and-deck-footings/

  14. Ken K
    June 17th, 2015 at 20:48 | #14

    Since the deck is unattached, I assume there is no “roof”. Are the walls are only secured to the concrete slab and to each other only at the corners? Or is there other bracing to keep them solid and square? Thanks!

  15. June 22nd, 2015 at 09:33 | #15

    @ Ken K, Yes, technically there is no roof attached to the shed walls. The roof is incorporated inside the deck joists. The walls are bolted to the concrete and to each other in the corners. They are not attached to anything else. They are not attached to the deck and they are not attached to the house wall. They are very very rigid (no bracing needed) and do not move or wobble because they are bolted to the concrete. The gap is between the top of the wall and the deck and is maybe 1-2 inches and is difficult to see. Look at 2 minutes and 20 seconds in the video and you can see I filled the gap with some foam to prevent wasps and small animals and stuff getting inside. There is a skirt board wrapped around the lower part of the deck (attached to the deck only) which completely obscures the gap from the outside and prevents high winds and rain from getting inside.

  16. Kelly Fritz
    July 4th, 2015 at 06:53 | #16

    Great project! I live in central NC and I’m considering doing the same thing under my screened in porch. I Don’t think I will have much to worry about water coming in through the roof since it is covered and we don’t get much of a winter so no heave. My questions are about how you poured your pad. Did you drill in your bolts? Thanks!

  17. July 4th, 2015 at 13:07 | #17

    @Kelly Fritz, I had a professional pour my pad. I wanted precise control over where my concrete bolts would go… so I drilled them in after the concrete had cured and set bolts in the holes with industrial concrete epoxy which is meant for this purpose.

  18. Patrick
    July 22nd, 2015 at 17:52 | #18

    Alan, I am impressed! Congratulations.
    Just moved to a house where there is a deck with nothing under.
    I’m trying to understand how you managed to concrete the floor of your shed with the two posts already installed. I believe you probably dug the area, right? How to maintain the posts at their places?

    Congratulations.

  19. July 22nd, 2015 at 21:06 | #19

    @Patrick… the posts were outlined with fiberboard material (the kind you see in concrete seams elsewhere). Then when the concrete was poured… it stayed 3/4″ away from the posts. Now the concrete can heave up and down in winter and simply slides around the posts. If you’re not looking too close.. the concrete looks like it touching the posts, but it has the fiberboard separation. Thanks for the good question.

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