Grading, by definition, is altering the slope of the Houston landscape between one point and the property and another. This is a vital, albeit little publicized element to residential landscape design.
Water runoff is one of the primary functions of landscape grading. Drainage is always a challenge anywhere we work on the Houston landscape because almost the entire city is completely flat. Virtually anywhere we build something, we must engineer strategies for getting excess water away from sensitive plants and expensive outdoor architecture.
Creating a grade is more difficult than one would assume. Beyond the exterior walls of the house (which requires flat terrain for a stable foundation), the yard has to have a certain level of slope and elevation to appear interesting.
However, to say this is one thing, to do it is another. Landscape architects cannot just randomly alter the elevation of an entire yard because it will harm or kill trees. Special zones of interest have to be carefully portioned in the landscape master plan, then graded appropriately to their intended function and desired aesthetic.
In a new yard, raising different parts of the Houston landscape can work toward creating different areas for outdoor rooms, special gardens, fountain areas, natural ponds, and lighted pathways. Raising the grade at one end of the yard can create special space that either invites guests into a secluded area, or politely says “for residents and family only.”
In a Houston landscape design that already has been extensively developed with pools, outdoor buildings, and pre-existing gardens, it is better to enhance existing grade than to attempt to force a new grade onto an area.
For instance, in project that we did a few years back, we graded the pool, and we left the patio high. This allowed us to both remodel the pool, and it created in a better focal point for gatherings. People sitting or standing around the patio can now overlook the water from an elevated perspective.
Another project of ours involved creating more interest around an outdoor room. What we did in this project was to raise the grade in the rest of back yard. In order to get to the outdoor room, a person had to step down from any other area of the backyard. Without this shift, the room would not have that feeling of interest.
To avoid harming trees, this was also done in a very subtle way. The total grade drop was only about 16 inches. In order to make it seem like more than that, we built the 4 four inches high rather than the standard 2.8 inches used on typical walkways. Four-inch steps gives a person a very real sense of lowering elevation, which on a Houston landscape is just enough to create the emotion and interest we were looking for.
Grading the landscape can be done in both front yard and back yard landscape design. In the front yards of larger estates, many people like to have an elevated patio or gazebo set aside for large outdoor summer parties that need both the front and back yards to accommodate all the guests.
Such events will no doubt have many cars parked in front of the house. To help prevent them from detracting too much from home architecture, the grade of the motor court can be lowered so that they are partially obscured from view.
In back yards, patios need to good drainage without obviously visible slope. In some Houston landscape projects, we may gradually slop the patio toward a large garden, using it as a catch basin of sorts.
If there is no nearby garden of appropriate size, we can build concealed drains into the hardscape every six feet to prevent fluctuation in grade beyond one inch and thus make the patio appear completely flat.