Hello, hopefully someone can help with a couple quick questions.
I am starting in the next week on about a 400 sq ft patio for the back yard. The yard slopes away from the house slightly so the patio will be raised but by no more than 10 inches along the edge furthest from the house. My first question is, since the height of the patio is less than 10 inches, can I use a wall block insted of a retaining wall block that has a lip on it? I would use construction adhesive between each block to help prevent movement.
I will be excavating 8 inches deep and back-filling with a road mix and compacting with a plate compactor. I will have a minimum of 8 inches of compacted road mix
I am also planning on building an outdoor fireplace. It is nothing huge but estimated at about 1100 lbs. Is this base strong enough to hold that weight or should I excavate deeper where the fireplace will be?
I would not use a common "wall block" for your purposes unless it set on a concrete footing and the joints were mortared.
I would use retaining wall block with lips to resist shear (set on a compacted base) and allow drainage from behind. After building the wall compact the base material, put in a 1" clean sand setting bed and set the pavers. Sprinkle sand on the pavers and vibrate the sand into the tight joints and run a vibratory plate compactor over the surface to vibrate the sand into the joints (increasing the strength and stability) and to true up or smooth the patio surface.
If you are using "stepping stones" (12" or more in any dimension), all the preparation will not do too much for and elevated paver installation.