Before you construct a trellis, fence, arbor or any outside structure, observe what happens on your yard when it rains. If there is standing water, then watch to determine how long it takes for the water to subside. Also think of how the trellis can change drainage patterns from your yard, perhaps diverting it towards your house or garden. If water becomes an issue after your landscape was developed, and the trellis was built, you may have a few options to siphon water off.
Both the kind of dirt and the shape of the ground influence drainage patterns from your yard. Generally, excellent drainage means your lot will shed water through a heavy rain, not leave puddles behind. Sandy soils drain fairly well, while heavy clay drains poorly. Contours from the land determine where the water will collect or drain during a heavy rainstorm. In case you have drainage issues on your premises, it’s a fantastic idea to repair the issue before building any outside structure that will make the issue worse.
Redirecting Minor Water Flow
One method of managing a minor drainage issue is to produce a shallow ditch, also called a swale, to direct runoff away from the trellis. In most cases, swales have shallow, sloping sides which you can line with little rocks to prevent the sides from caving in. You can also plant bud or groundcovers round the swale to absorb water. If you don’t have a water problem in your yard, a standard trellis shouldn’t cause one, simply due to the inherent, open lattice design.
Big Scale Drainage
If you do have a issue, consider how building a brand new structure will change the drainage patterns. For example, a trellis, while normally a simple structure with vertical planks and spacing between, shouldn’t, theoretically, change water flow in a yard with great drainage. But any good board in the base, similar to a kick board on a fence, can block water leak, flooding the area on the side. If standing water is a issue, consider installing either a French drain or a dry well to redirect standing water into an area where it can either be absorbed or directed into a public drainage system.
In areas subject to frequent freezing and thawing, wet, loamy or fine-grained soils go through a condition called “frost heave,” which causes the dirt to shift, frequently pushing the vertical supports of a fence or trellis, weakening the structure. To prevent frost heave, the poles or supports should be set in holes containing a gravel sub-base which makes it possible for the gravel to shift, but not the post, so long as the sub-base is beneath the frost line.