We started building a shed in our garden. Now we would like to close the sides using wooden planks. To keep the wood in a good state as long as possible we want to leave a gap between the lowest plank and the ground, but don't want water to run into the shed. How could we close that gap? Any ideas what material would be best to use?

We thought about trying to build a concrete lip all the way around but this would be difficult for us and we aren't sure if it's the best way.

Long side of the shed

  • Even with a plank going down to the ground you wouldn't get that really waterproof. Can you make the shed's floor higher than the ground around the shed? Also take care of that small space between your wall and the neighbor's wall. This is a great place for all kinds of weed to grow as it likes.
    – puck
    Aug 22 '21 at 16:03
  • 2
    You could use cement board (eg "HardiePlank") for the bottom course and it would never rot. (Go for a thicker one, as the thin -- 1/2" or so -- are really delicate.) Aug 22 '21 at 16:50

I’d install 2x4’s horizontally at about 24” on center to the exterior side of the posts. (The bottom horizontal 2x4 should be pressure treated.) Then I’d install a cheap wall sheathing (if required for seismic active area or high wind area.)

If not required, then install a moisture barrier directly to the 2x4’s. The reason we install a moisture barrier is because we know the siding will leak. Wind and rain will “push” moisture into the wall system and cause dryrot.

Then I’d install the siding (the boards you described) vertically letting them span from horizontal 2x4 to horizontal 2x4. I’d make sure the boards lap the bottom horizontal 2x4 by about 1”. This will give a “drip” so water can’t “wick” back up into the wall.


Installing horizontal 2x4’s allows a moisture barrier to be installed to protect the existing posts, etc. The posts are not pressure treated (no incising) but may be decay resistant if it’s cedar or redwood, but they will eventually rot. For added protection, you can add a metal strip (called “Z-flashing “) to the very bottom of the wall to protect the end grain of each vertical board from water and pests.


I see no reason you could not use treated lumber, it appears to me to be the simplest solution. It would probably blend better than any other type of material.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.