Hello! I stumbled onto this website doing some research on residential irrigation systems for my own home and decided to look into this forum as I've done hundreds of wall designs and provided countless recommendations for subgrade preparation and construction for all sorts of paving and I am always curious what the contractors are doing. Yes, I'm a licensed engineer, and practice structural and geotechnical engineering in the States of NY, NJ, PA, DE, and MD. I also have about a half-dozen regular hardscaping contractors as regular clients. Anyway, in reading some of the questions and responses here, in particular those pertaining to retaining walls, I was left with an unsettled feeling due to the seeming lack of understanding and knowledge about building codes, design, and construction of walls... I am curious how often some of you consult with an engineer, whether a private engineer or one who works for the manufacturer of the segmental products you may be using? Also, how many of you rely solely on the local code officials for requirements versus verifying the building code yourself because height is only one discriminator in the need for design in most of the codes? How about inquiring about suitability of backfill - e.g., clean 1" minus material is not necessarily the best choice for backfill when the native soil is a fine sand and silt. I'm not here to bash, nor do I mean to intrude. I'm sincerely curious and wonder if we engineers should be marketing hardscapers more to promote better understanding for the need for good design and/or site-specific construction recommendations. True, for the professional engineer such work is small potatoes, but I know I like the work for my younger engineers to develop on and it makes a decent filler between the money work.