ᐅ Foundation for a garden shed with approximately 364 cm x 304 cm external dimensions

Hello everyone,

I have used the search function, but couldn’t really find anything suitable for my problem since it won’t be a tool shed.

Here’s the situation: we want to buy a small garden house with the dimensions mentioned above (maybe even 400cm x 400cm (13 feet x 13 feet)). This will serve as a shelter for us during the construction phase and later as a guest house.

So, of course, I tried to find out which type of foundation would be best. Unfortunately, I didn’t come to a clear conclusion because there seems to be different advice everywhere. What would you suggest? I somehow tend to think a pier foundation might be suitable, but I am not sure if that’s the right choice. Or would it be enough to remove the soil (but how deep?), then add crushed stone, then gravel, then a weed barrier, then sand, and finally place concrete slabs or paving stones on top? And then put the floor of the house on that?

Thanks for your help.

For a garden shed of that size, I would simply have a foundation poured. If construction is already planned, it should be quite easy to do "on the side." That's what we did as well – the surface is level and stays that way.

But construction will start later; the building application has not even been submitted yet. However, the house is supposed to be delivered soon.
Otherwise, you are of course right, it would be an easy task.

I would simply excavate the topsoil, add some gravel, and then pour a small concrete slab (10-15cm (4-6 inches)) on top.
Although this isn’t 100% correct (not frost-protected foundation), it should be sufficient for a small garden shed.
This way, you’ll have a permanent, solid, and stable base and won’t have to worry about uneven slabs or similar issues again.

But do my dimensions still count as a "small garden shed"? I mean, it’s not a tool shed 🙂
What do you think about a pier foundation? Driving these kind of pipes into the ground, filling them with concrete, adding concrete footings, and then screwing the floor of the house onto them.
Somehow, I’m torn back and forth...

You should check the local building regulations to see up to what size your house can be built without a permit. For example, here in Lower Saxony, I believe only houses up to 30 cubic meters (1,059 cubic feet) are exempt. For anything larger, you will need approval.