DIY dry shed under deck, concrete floor, retainer wall
Sorry for the re-post in this forum. After reading the descriptions of the forums, I realized that I may have posted this to the wrong forum. Apparently several hundred people viewed it but nobody said anything.
I am new to this forum and this is my first post. I am happy to become part of the forum. I live in Landenberg, PA (19350) - the extreme SE corner of PA, very close to the border with DE. I am a scientist/engineer, but not this kind of engineer.
I have a large back deck. Under one half of it is a dry shed with a concrete floor, a flat sloped roof with gutters, and locked door and walls. This is all hidden under the existing deck. Water (rain) drains down through the gaps between the deck boards. The proper roof and gutters keep everything completely dry.
Under the other half of the same deck is currently a dirt floor which I have dug out. On this side the water (rain) drains down through the gaps between the deck boards and drips down onto the dirt. I want to make this a dry shed also. My questions have to do with a new concrete floor and a retaining wall on the side where I have dug out the dirt, leaving an earthen wall about 3.5 ft high in the back right corner and about 1.5 ft high in the front right corner. None of this will attach to my house's foundation, nor will it bear any weight from the deck above.
To make the floor flat I had to dig out quite a bit of sloping ground, leaving an earthen wall on the right side. My basement foundation wall is along the back edge, and the outside wall of the existing dry shed is on the left edge of the area in question. The area is about 18 ft deep and 12 ft wide. There is a slight slope in the grading of the yard that will cause water to drain toward the outside of retaining wall.
Here are my questions:
1.) What makes sense to build first, the concrete floor or the retaining wall?
2.) I plan to build the concrete floor in quarters, using forms and half-inch felt spacers between the sections. The plan to do the floor in sections is because I can't get a truck in to pour concrete, and therefore I plan to mix the concrete in a wheel barrel and work in small batches. Does this make sense?
3.) I plan to grade the dirt floor sloping away from the back foundation wall with a slope of about 1 inch of drop per 12 inches of run. I plan to put down about 2-3 inches of crush-n-run before pouring the concrete, with no rebar or metal. Does this make sense?
4.) For the retaining wall on the right edge I plan to either make a form and pour the wall using bags of concrete, or use cinder blocks, depending on the advice I get here.
5.) Outside the wall (where the water will certainly build up) I will put in a 4-inch drain tube and silt sock surrounded by crush-n-run in the usual manner, with a slope of about 1 inch of drop per 12 inches of run, exiting a few feet out from what will be the front of the shed. Above the crush-n-run stones I will back-fill with dirt, compacted every 6-8 inches deep by a hand pounder.
6.) If the advice I get here is to use *cinder blocks* for the retaining wall, I plan to pound in half-inch vertical rebar a few feet, and fill the channels of the cinder block with concrete. The outside of the wall will be rolled with foundation tar as a water barrier. Does this make sense?
7.) If the advice I get here is to use *bags of concrete* to pour the retaining wall into a form, I plan to use half-inch rebar every 12 inches in the vertical and every 12 inches in the horizontal directions. The wall will be about 6 inches thick, 4 feet high in the back, and 2 feet high in the front. The outside of the wall will be rolled with foundation tar as a water barrier. Does this make sense?
8.) For either the cinder block or poured concrete wall, would you use some kind of anchoring system from the wall into the earth behind the wall? I am thinking of a kind of rebar with an auger tip on one end that would get screwed into the dirt before pouring the wall. I could also dig vertical holes for 4-by-4 wood posts about 2 to 3 feet away from the wall and use half-inch horizontal threaded rod with nuts on the 4-by-4 end, and tie it into the rebar on the retaining wall end. Does this make sense, or it is over-built?
Thanks in advance for your advice and suggestions.
Landenberg, PA 19350
SE corner of PA, near Newark, DE