In Guild Wars 2, when casting an existing buff (boon) or debuff (condition), rather than overwriting the current buff (or debuff), it will apply it's own separate effect. The wiki explains that these effects will stack with previous applications, either by stacking the intensity (ie. Casting the same Might spell twice will double the effect), or the duration.
The wiki explains how boons stack in intensity.
Is there an upper limit to the intensity (either by number of stacks, or total effect) to any buffs or debuffs?