shed foundation

Hi all,

not sure if this is the correct place to ask about this topic?

I have a wild flower garden, about 150 m2, not too big - and I would like to build a small shed in this garden to store my garden tools and bicycles. It will measure 220x400 cms.

All the people I spoke to recommend me building a concrete or masonry foundation, preferably below frost leven underground. (< 40 cm)

This feels like a lot of cumbersome work. I love working with wood, and have a lot of used construction wood. I can lay bricks, but the idea of burrying heavy building materials just doesn't appeal to me: I dug a lot of of construction waste from previous owners, like bricks and tiles and cement, and it feels rather permanent to build a heavy foundation. At the same time, I don't want it to degrade or sink quickly...

I have tome old 30x30x5 concrete tiles left and got the idea to pile them up, just dig them in for about 30 cms, let them protrude 20 cm above the grond, and put a grid of wooden beams on them. I would use 3x5=15 tiles in total to support the shed.

My friends tell me the shed will sink / tilt, or get blowed away by wind and my idea is questionable.

The reason I at least have some trust in my construction is because I built a wood storage shed and its feet rest on just 1 brick and it doesn't visibly sink or tilt.

The shed will be 460 cm tall, and build with wood. The roof will have old stone tiles.

Any idea or advice if my idea is ok or not, or other options? I also like the idea of putting an array of beams just in the ground, but  they will rot over time. I see people burning the surface to protect them from rot, but I think they will eventually rot. I want to use cheap pine wood beams, as this is what I have. (used wood)  

The picture in the attachment demonstrates my current idea, the green parts are the concrete tiles.

           

Dear hubby and I have built severl sheds.

They have all had a concrete block foundation.

First we leveled the ground using rakes and shovels, marking the area with string.

The level part is very important.

Then we placed concrete blocks at all four corners.  The amount of blocks depends on how many it takes to get the building level.

The picture in the attachment demonstrates my current idea, the green parts are the concrete tiles.

This looks good as long as everything is level.

Thanks for your respone Anne!

Can you tell me whether or not you put the tiles below ground, and if so, how deep?

one difference between our implementation would be that in my case the tiles  are loosely stacked, they are not one physical body, but just a stack of tiles. Personally, I would think this won't be a problem, as the weight / gravity of the building, wich wil be several thousands kilograms (estimate) will prevent them from any movement.

I can connect them using mortar, but I like to keep things as dismountable as posible...

I think a big consideration is the spot you are putting the shed on compared to your frost heave.

I have a 'floating' shed of many years that has just started to succumb to frost heave/groundhogs. It also is right next to a hillside which has not done it any favors.

My next build is going to be put up on bulky skids that then might go on top of leveled stone pad.

I'd mount it on skids that are designed to be replaced. Then I'd shim it with rocks/bricks/concrete pavers/wood scraps/etc to level it. If the skids rot in ten years, swap them out. If frost-heave changes the level, just reshim with more rocks. And many places, structures on skids aren't taxed like "real" buildings.

John Bos, I totally understand you desire to "keep it simple". A lot depends on your ecosystem and weather patterns.

I built a 5'x10' shed just on the ground once with a "shed" roof that faced the common prevailing wind - I needed something fast. It was very light weight. I saw the wind tip it up. I added a rebar stake and a guy line to solve the problem.

It had to move to make room for another project. When I was finally ready to reassemble it in what I hope to be its 'forever' location, I put rebar stakes near each corner and fastened it to them - no guy lines is a good thing!

However, I'm observing, and reading, that storms are getting bigger and showing up in unexpected locations. There are a variety of materials you can stake into the ground and tie your building down to. They don't have to be fancy or expensive for a shed, but I do think it's worth the effort. However, I'm basing that opinion on my own eco-system.

Hi, thans for all your responses! I think I will just build and see if it works out...

hi,

I decided to make a foundation after all, after doubts, to be sure that the shed is well fixed.

Now I want to make the foundation as durable as possible, so with reused materials. I myself thought of old, used, monastic bricks that I was able to find at a local store. But later I discovered that these bricks come from Hungary, which is about 1400 km away from where I live. I am curious now, whether the environmental impact for transportation will be greater or lesser than producing new bricks. Do you perhaps have any idea about that?          

I don't see where you are in the world, but as you're using metric measurements more likely not from the USA. Which country are you in, or what is the temperature range you have in your country? As others have said frost heave could be an issue. I'm in the UK and built a building very similar to your image. In the UK it can get down to maybe -10c in winter but not much lower.

You are asking about materials that are a long distance away but as you can hide these foundation materials once you build your building why not just use old breeze blocks? These are common all over the world and usually given away in the 'free' and 'freebies' sections on facebook and other local freely given material websites, so there's probably someone only a few miles from you wanting to get rid of some. It's a good way to recycle them.

Assuming you don't get below -10C or so in your area, if you dig and bury one layer of these into the ground for the points where you need to support the building, then use a 2nd layer above the ground to raise the building off ground level, and then you insulate the floor of your building, you can then board up the air gap under your building (HEAT TREATED pallet wood marked HT on pallets is good as it's free from chemicals, and given away free, and easily replaceable) and the ground will never freeze and frost heave would be no issue.

Oh and I forgot to mention, you'll need some diagonal bracing with your building or it'll end up in a heap on the ground after a strong wind!

I have constructed pallets for many years here in the USA. The pallets I constructed where made from plain red oak.

@Bri England: thanks for the suggestion! I will add some vertical diagonal bracing. I live in The Netherlands; it rarely gets below -10 Celcius nowadays...

@John F Dean: thanks for the idea!

Hi, plans have changed drastically: I finally decided to build a mansonry wall, which protrodes 10 inches above ground level. I used (very) old bricks (over 100 years old); I'm very pleased with the result! This will keep the wood construction elevated from the moist ground, wich is a good thing I think. It also anchors the building to the ground, so these problems are solved. I added 12 open head joints, for under-floor natural ventilation. Those joints are about 0,5-1 inch wide. Some people warned me for mice.

The general opinion seems one have to keep mice out of your shed (basement). But before adding grids to block entrance for mice, I was wondering if this is really an issue? What if I just don't prevent these mice from visiting my shed basement, what would be the worst thing that could happen? I have no electrical wires in my shed, nor any food. I will store only bicycles and garden tools in my shed, but this is above floor... I'm curious about your opinions!

John Bos wrote: What if I just don't prevent these mice from visiting my shed basement, what would be the worst thing that could happen?

Stinky mouse pee and stuff chewed on (they'll chew anything even if it isn't food, to make bedding out of). If you give them cheap housing, they will go elsewhere to find the food. Mice chewed open my peppers last year as an example. If they'd just eat one, I'm tolerant, but mouse bites out of all of the nearly ripe ones resulted in me having to set traps and I always worry about getting non-target species.

A bit of 1/2 hardware cloth secured over the holes should discourage them. If it were me, I would do so.

They carry diseases, and, while at the moment, you're only storing bikes and garden tools there, as you just noted, sometimes "plans have changed". It's possible that later, that space may be needed to store other things, too. Plus, as Jay mentioned - they'll chew on anything - including rubber, wood, vinyl, etc, that make up bike seats, bike & tool handles... And, they not only poop on everything,  but their urine is acidic, and will damage metal, & soak into & damage wood. Also, if mice can get in, other things will eventually figure out where the mice are, and start digging to get to them.

My feeling is, it's rarely a bad idea to prevent mousage.