Certain obstructions will either hinder, limit or prevent placement of the termiticide into the soil where it needs to be placed to be effective and certain factors will adversely influence or disrupt the termiticide soil barrier following treatment.
Obstructions which hinder, limit, or prevent placement of termiticide into soil where it needs to be placed to be effective and factors which disrupt or adversely affect termite soil barriers (not in any particular order):
1) Acts of Nature (earthquakes, floods, drought and the cracking open of soil due to evaporation, freezing/thawing conditions, erosion, and high or fluctuating water table in treated soil areas;
2) Placing new dirt or mulch over treated soil;
3) Placing wood (fire wood or other) adjacent a treated structure;
4) Placing storage or debris adjacent a treated structure;
5) Structural water problems can support live termite infestation within a building, even when the soil barrier is effective;
6) Digging and/or removal or addition of plants in treated soil (includes, but is not limited to, regrading and planting following pre-construction and or existing construction soil treatment);
7) Plant root growth;
8) Adding new construction over and/or beyond treated soil;
8) Adding new construction over and/or beyond treated soil;
10) Sprinkler systems;
11) Vegetative obstructions;
12) Construction obstructions (styrofoam between foundation and soil, wood forming boards left in ground, and any debris in/under backfill);
13) Structural obstructions;
14) Soil obstructions (clay and/or gumbo, rocks, roots, backfill debris, pipes, and etc.);
15) Storage obstructions;
16) Microorganisms in the soil;
17) High organic content in soil;
18) Leaching,
19) Soil texture: Certain termiticides work better in certain soil textures than others, and;
20) The natural degradation of the termiticide.

TAKE NOTE: The treating company has no control over any of the above listed twenty (20) factors which either obstruct treatment (placement of termite into the soil where it needs to be placed to provide effective control) or disrupt or otherwise adversely affect existing soil barriers. Now you know why all termite soil treatments are limited as to extent and effectiveness. Due to the aforementioned factors, there is no such thing as a perfect termite soil treatment.