I'm designing some outdoor bike storage as a free-standing shed. It will go against a house on an existing cement driveway. We're renting, so I can't drill into the driveway or do any other permanent modifications.
Here's my current design for context:
Link to the public design in OnShape: Bike Storage Shed
Edit for clarity:
The rough size of the shed is 4 x 12'
I have two goals for the post bases:
Allow leveling.
Keep ground moisture from damaging posts.
This structure is in coastal northern California, so no snow load on
the roof but occasional heavy rains.The structure as shown is not done being designed yet; there will be framed
out T1-11 siding on the ends and diagonal braces in the back to provide
torsional stability.
It doesn't seem right to just have the 4×4 posts rest directly on the cement driveway. What is the best way to support the posts? I was considering:
- Let end of 4×4 rest directly on cement, paint the end with exterior finish for some extra moisture protection. Hope for the best on the levelness of the driveway.
- Use cement pier blocks like these, adding sand/gravel underneath to get them level.
- Use pressure-treated lumber skids attached underneath the posts, adding sand/gravel underneath to get them level.
- Attach plastic standoffs like these to provide protection from moisture.
Any thoughts on the most robust way to interface the posts to the driveway?
Best Answer
+1 option #4, plastic standoffs.
"Any thoughts on the most robust way to anchor the posts?"
You said you are renting and can not anchor.
Take some five gallon buckets and mix up some cement, fill the buckets with the cement and put an eye bolt in so it stick out of the top. Put a nut and washer on the threaded part of the eye bolt that will be in the concrete to prevent it from being pulled out. Now you can place these on the sides of the structure and use rope or ratchet straps to secure the structure down to protect the wind from taking it for a sail.